Semi-Automatic Distillation Unit: Operating Manual
Semi-Automatic Distillation Unit: Operating Manual
Semi-Automatic Distillation Unit: Operating Manual
Safety warnings:
Before using the unit, please read the operating manual supplied with the apparatus
carefully.
SAFETY PRECAUTIONS
In order to prevent the risk of electric shock, fire and personal injury when the unit is in use,
basic safety measures must always be taken including:
Ensure that liquids do not come into contact with the electric power cable or with the
electrical parts of the instrument.
Check that the power supply corresponds to the rating plate on the rear of the unit.
When replacing the power cable, make sure that the new cable has the same
characteristics as the original and that it is earthed.
Do not use the unit if it is not working correctly. In case of malfunctioning, contact your
nearest service centre.
The personal protective equipment must be compatible with the possible risks posed by
the material being processed and the glass of the containers.
The test tube reaches a temperature of 100°C during distillation and also during the
cooling phase. Use the pincer supplied to remove the test-tube at the end of distilling.
The vessels and the products used during the work-cycle must be compatible with the
temperatures reached by the unit (approx. 100°C).
For further information on the handling of the reagents see Chapter 2 “Chemicals”.
Leave the transparent guard in place when the unit is running.
Follow the cleaning instructions described in this manual
The safety of the instrument is no longer guaranteed in the case of improper use or if the
instructions in this manual are not followed.
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RÈGLES DE SÉCURITÉ
Pour éviter tout risque de choc électrique, incendie ou blessure corporelle pendant l'utilisation
de l'appareil, toujours appliquer les mesures de sécurité de base, y compris les
recommandations suivantes :
S'assurer que les liquides n'entrent pas en contact avec le cordon d'alimentation ou avec
toute autre pièce électrique à l'intérieur de l'appareil.
Vérifier que le cordon d'alimentation est inséré dans une prise électrique (dans une
position facilement accessible) correspondant aux valeurs décrites sur la plaque de
l'appareil.
Utiliser uniquement des cordons d'alimentation à trois bornes, c'est-à-dire avec cordon de
mise à la terre.
Ne pas utiliser l'appareil en cas de dysfonctionnement. Si cela se produit, contacter le
Service Après-Vente le plus proche.
Les équipements de protection individuelle doivent être compatibles avec les risques
encourus pour les matériaux à traiter et le verre des récipients.
Le tube à essai atteint une température de 100°C pendant la phase de distillation, mais
également pendant la phase de refroidissement. Utiliser les pinces fournies pour retirer le
tube à la fin de la distillation.
Les récipients et les produits utilisés pendant les analyses doivent être compatibles avec la
température réglée sur l'appareil (environ 100°C).
Pour toute autre information sur l'utilisation des réactifs utilisés, voir Chapitre 2 “Produits
chimiques”.
S'assurer que la protection transparente est en place lorsque l'appareil fonctionne.
Respecter les instructions d'entretien de l'appareil décrites dans ce manuel.
Le fabricant décline toute responsabilité pour toute utilisation de l'appareil non conforme à ces
instructions.
This unit has been designed and produced in compliance with the following standards:
Safety requirements for electrical apparatus for
measurement and control and for laboratory use IEC/EN 61010-1
IEC/EN 61010-2-010
IEC/EN 61010-2-081
UL Std. 61010-1 2nd Ed.
CAN/CSA 61010-1-04 2nd Ed.
CAN/CSA 61010-2-010-04
CAN/CSA 61010-2-081
The manufacturer is committed to constantly improving the quality of the products and reserves
the right to modify the characteristics without prior notice.
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CONTENTS
1.1. Parts included.......................................................................................................... 6
1.2. Instrument description ............................................................................................. 7
2. Chemicals .............................................................................................................. 10
2.1. Products used ....................................................................................................... 10
2.2. Substances generated by digestion and distillation ................................................ 11
3. Assembly and installation ....................................................................................... 12
3.1. Hydraulic connections ........................................................................................... 13
3.2. Connection to the electric power supply................................................................. 14
3.3. Connection to external devices .............................................................................. 15
3.4. Printer 15
3.4.1. Mouse .......................................................................................................... 16
3.5. Preliminary operations ........................................................................................... 16
4. Using the menus .................................................................................................... 17
4.1. Quick Guide .......................................................................................................... 17
4.2. Main menu ............................................................................................................ 19
4.3. Analysis 21
4.3.1. Wash-down .................................................................................................. 21
4.3.2. Distillation .................................................................................................... 23
4.4. Methods 26
4.5. Set-up 28
4.6. System 31
4.6.1. Check-up ..................................................................................................... 31
4.6.2. Calibration .................................................................................................... 38
4.6.3. Maintenance ................................................................................................ 39
4.6.4. Service ......................................................................................................... 40
5. Operating Controls ................................................................................................. 42
5.1. Safety devices, signals and warnings .................................................................... 42
5.1.1. Safety devices .............................................................................................. 42
5.1.2. Reserves and overfilling ............................................................................... 43
5.1.3. Warning signals and messages .................................................................... 44
5.1.4. Black-out ...................................................................................................... 45
5.2. Graph of steam production .................................................................................... 45
5.3. Graph of tap water consumption related to the water flow rate and temperature .... 46
6. Work cycle ............................................................................................................. 47
6.1. Analysis 47
6.2. Devarda’s analysis ................................................................................................ 47
7. End-of-work operations .......................................................................................... 48
8. Maintenance .......................................................................................................... 49
8.1. Routine maintenance............................................................................................. 49
8.2. Extraordinary maintenance .................................................................................... 50
8.2.1. Periodic maintenance ................................................................................... 50
8.2.2. Operations to be performed only when necessary ........................................ 52
8.3. Expedients for transport......................................................................................... 53
9. Disposing of the unit............................................................................................... 54
10. Accessories ........................................................................................................... 54
11. Spare parts ............................................................................................................ 55
12. Technical features .................................................................................................. 56
13. Wiring diagram ....................................................................................................... 58
14. Hydraulic scheme .................................................................................................. 60
15. Warranty 62
16. Suggestions ........................................................................................................... 62
17. General description of Kjeldahl's method for the measurement of organic Nitrogen 63
18. AOAC, method 960.52, Microchemical determination of nitrogen- Micro-Kjeldahl
method .............................................................................................................. 68
19. Analytical procedure Typical analytical scheme for organic Nitrogen ...................... 70
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Introduction
Steam distillation is applied in the laboratory for the fractionation of water insoluble
liquids or solids according to Dalton's law of partial pressures in a gas mixture.
It is also used for stripping chemicals from mixtures or solutions after displacement of
the ionic equilibrium by adding acids or bases, as in the well known Kjeldahl's
method for total Nitrogen determination.
The Kjeldahl method remains the most used method for determining Nitrogen and
protein contents in foods and feeds (official methods).
This is simply due to its precision and reproducibility.
Since its initial design, many improvements have been introduced aimed at reducing
energy consumption, space requirements and sample quantities.
The UDK 139 Semi-automatic Distillation Unit has a color touch-screen with
electronic control for simple and user-friendly programming of parameters such as
distillation time, the volume of reagents such as sodium hydroxide, water and the
regulation of steam production from 10 to 100% in order to carry out Semi-automatic
distillation.
By modifying the distillation time and steam output it is possible to carry out fast or
slow distillation according to the product being analyzed. For example, the distillation
time for the determination of the protein content according to the Kjeldahl method
can be reduced to three minutes. In other cases (e.g. volatile acids in food products),
the distillation time can be increased to 30 minutes or more.
Analysis times are reduced thanks to the optimization of the applications:
10 programs that can be customized directly by the user.
NOTE: the software can be browsed directly from the touch-screen. Select the option
by hand, using a stylus or a mouse.
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NOTE: Keep the special shock-resistant packing material for future use.
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1
6
2
9 3
8
10
11
5
The UDK 139 Semi-automatic Distillation Unit uses innovative technology and
advanced electronics for the automation of the various stages and the highest
standards of reliability and safety.
The UDK 139 carries out all the stages of the distillation process such as the addition
of single reagents and the removal of distillation residues automatically.
The Semi-automatic distillation unit UDK139 is fitted with innovative devices and is
manufactured using innovative materials and advanced technology:
The patented Velp Scientifica steam generator uses deionised or distilled water
and produces a constant and stable quantity of steam ensuring the
reproducibility of the analysis without requiring any routine maintenance. The
steam flow is controlled by a software which enables the user to choose
between rapid or slow distillations according to the product to be analyzed.
The innovative titanium condenser achieves outstanding heat exchange,
reduces water consumption, offers higher resistance than glass and is easily
and thoroughly cleaned. The display shows the water consumption during each
analysis.
The new technopolymer splash head assures optimal resistance to the high
temperatures and corrosive chemicals involved during the distillation process.
The graphic touch screen with its simple and user-friendly interface, enables
the user to program all the automatic distillation / titration parameters. The
protective film on the touch screen safeguards against wear and against the
majority of laboratory agents.
Choose from 6 different languages to communicate with the instrument.
The distillation unit can be connected to a printer via USB in order to print all the
information pertaining to the tests performed in accordance with GLP (Good
Laboratory Practice).
The UDK 139 ensures the highest safety standards: it signals the absence of
the test tube, test tube exchange at the end of analysis, safety guard open, the
absence of reagents and the absence of cooling water. The use of an innovative
system enables the operator to position the test tube in complete safety and
means that test tubes of various sizes can be used.
In a world where respect for the environment is increasingly important, the
distillation unit UDK 139 makes a significant contribution to this cause. The
cooling water supply shuts-off automatically during pauses considerably
reducing water consumption and the technopolymer housing is 100%
recyclable.
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The UDK series guarantees unmatched savings whist ensuring an extremely high
level of reliability.
Energy: Cooling water consumption starting from only 0.5 l/min; excellent insulation
of internal parts.
Space: The extremely compact footprint saves useful laboratory bench space.
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2. Chemicals
2.1. Products used
The chemicals used for distillation and titration are potentially dangerous and must
be handled with care and with personal protective equipment: gloves, goggles and
pincer removal of the reaction hot test-tubes.
1) Boric acid (H3BO3): 4% solution. The low concentration is due to the fact that
boric acid crystallizes at low temperatures and this can cause problems in the
hydraulic circuits of the instrument. Ingestion or absorption may cause nausea,
vomiting and diarrhea. Diluted solutions are used as an antisceptic.
4) Hydrogen peroxide (H2O2): 30% w/w. Can cause severe burns. Wear goggles
and rubber gloves. Avoid contact with combustible materials: drying of concentrated
solutions on paper, clothing and so on, can cause combustion. Heavy metals and
their salts, dust, irregular surfaces, can cause rapid decomposition resulting in the
production of oxygen and increased pressure. Stored hydrogen peroxide solutions
decompose slowly but nevertheless bottles must be fitted with vent caps. Empty
bottles must be rinsed with clean water. In case of contact, rinse immediately with
plenty of water.
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NOTE:
The instrument weighs 31kg. If you need to move the instrument suitable
lifting devices should be used.
Do not remove the protective film from the touch screen.
Position the instrument near the socket power supply because it is
considered a means of disconnecting the device
The instrument must be placed near a water tap (necessary for cooling the distillate)
with a maximum pressure of 5 bar, and sink in order to discharge the waste water.
The instrument requires a tap water flow rate (depending on the temperature of the
tap water) of approximately:
Water is required during the distilling phase only and is interrupted automatically
during the other phases.
Position the tanks for NaOH and H2O solutions and for collecting distillation residues
below or behind the unit. The tanks are not supplied with the instrument because
their volume is chosen according to specific requirements. Usually polythene carboys
of 5, 10 or 20l are used.
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IMPORTANT
Place the carboys for the H2O and NaOH solutions on the floor and not at the
same level as the unit on the bench in order to avoid air locks in the suction
tubes.
The sodium hydroxide tubes must be kept full or, alternatively, the tubes can be
emptied and washed at the end of the work cycle. This precaution will avoid the
formation of crystals when the solution comes into contact with air which may
block the tube and prevent the instrument from working correctly.
If the level sensors and full sensors are not plugged-in the instrument will
operate normally but the reserve and full indicators will not be functional.
NOTE: the mains switch can be used to disconnect the instrument from the power
supply when not in use in order to reduce energy consumption.
NOTE: When the service door is opened the power supply cuts-off automatically.
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3.4. Printer
Connect the printer (item code A00001009) to one of the two USB ports in order to
obtain automatic print-outs at the end of analysis.
The serial port configuration of the printer should be:
Baud rate 4800
Data length 8
Parity None
Bit of Stop 1
Handshaking None Xon/ Xoff
For printer connection a USB/RS232 serial converter cable is required (item code
A00000195). Connect the RS232 converter plug to the printer and the USB plug to
the USB port on the instrument.
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3.4.1. Mouse
A mouse with USB plug can be connected to one of the two USB ports to navigate
the menus. Connect the mouse with the instrument turned on in order to activate the
pointer.
NOTA: to position the test tube hold the blue handle down, slide the test tube into
place making sure that the Teflon tube remains inside the test tube and that the test
tube itself rests on the press test tube. Release the blue handle.
Close the safety guard;
Turn on the tap water;
Check that the distillate tube is in place in the flask.
Turn the instrument on by pressing the mains switch POWER (led on) on the right of
the instrument. The instrument automatically carries out the following steps
simultaneously:
Preheating (this takes 3 minutes. A yellow strip at the top of the display
reading “preheating” indicates that preheating is in progress, the
countdown indicates the time left);
Tap water check to ensure the presence of cooling water;
NOTA: During pre-heating the instrument menus can be accessed with the exception
of work cycles requiring the production of steam.
An acoustic signal indicates that pre-heating is complete, the strip at the top of the
display is blue and reads “UDK139”.
IMPORTANT: before beginning analysis enter the CHECK-UP menu in order to
fill the tubes (see chapter 4.6.1).
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Analysis ● Wash-down
● Distillation
Methods
Set-up ● Date
● Time
● Language
● Frequency
● Keyboard
sounds
● Lab. name
● Print ● Type
● Automatic
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The yellow strip at the top of the display (present on every page of the software)
indicates that preheating is in progress and shows the time left. During this phase it
is possible to navigate all the menus and submenus with the exception of work
processes that require steam production. An acoustic signal informs the operator that
preheating is complete. The band at the top of the display is now blue and reads
“UDK139” as well as giving the current date and time.
The second line gives the name of the menu viewed.
The main menu consists of 8 submenus that can be selected using the touch screen
or the pointer of the mouse (where present).
The "Main Menu" consists of the following submenus:
1. Analysis
1. Wash-down
2. Distillation
2. Methods
3. Set-up
1. Date
2. Time
3. Language
4. Frequency
5. Keyboard Sounds
6. Lab. name
7. Print
4. System
1. Check-up
2. Calibration
3. Maintenance
4. Service
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In each sub-menu the arrow in the upper left corner allows you to return to the
previous screen.
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4.3. Analysis
Select "Analysis" from the main menu:
To return to the main menu press the arrow in the upper left corner.
4.3.1. Wash-down
During wash-down distillation is carried out using distilled water as a reagent in order
to “wash” the internal parts of the splash head and condenser. Wash-downs can be
carried out at any time.
Use the touch-screen to select "Wash-down", the following window appears:
Pressing “Distillation time”, the alphanumeric keypad appears. Use it to set the wash
down time: min 2:00 – max 7:30.
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To return to the “Wash down” menu press the arrow in the upper left corner.
Pressing “Empty test tube”, it is possible to select or not the residues removing at the
end of wash down, with “Yes” or “No”.
To return to the “Wash down” menu press the arrow in the upper left corner.
To return to the “Analysis” menu press the arrow in the upper left corner.
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The green flag on the right indicates that the phase was carried out correctly, a red X
indicates that the phase did not terminate correctly. The blue line at the bottom of the
display indicates the cooling water flow rate (e.g. Tap-water flow = 1.2 l/min).
4.3.2. Distillation
Select "Distillation” from the "Analysis" menu. The following window appears:
To return to the “Analysis” menu press the arrow in the upper left corner.
Select the various fields and enter the required analysis parameters.
Press Method to access the "Methods" menu (see Chapter 4.4 Methods). Choose
the method of interest.
Press Operator and use the alphanumeric keypad to enter or modify the operator
name. Press to confirm.
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Enter the sample name (max. 13 characters) using the alphanumeric keypad.
Press to confirm.
Press Q.ty of sample and enter the sample quantity using the alphanumeric keypad:
Use the touch-screen to select the unit of measure required and press to
confirm.
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Position the test tube containing the sample in its seat and press .
During the distillation the following three phases are carried out in sequence:
- Add reagents
- Analysis
- Residues removal (only if previously selected)
The green flag on the right indicates that the analysis was carried out correctly, a red
X indicates that the phase did not terminate correctly.
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Press or the "Distillation" arrow top left to print the analysis data (if automatic
print-out has been selected) and return to the "Distillation" menu in order to with a
new analysis.
4.4. Methods
Select Methods from the "Main" menu.
To return to the “Main” menu press the arrow in the upper left corner.
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NOTE: upon receipt of the instrument all customizable methods include default
parameters entered by Velp.
Use the touch-screen to select each parameter and modify the value.
Select Method and use the alphanumeric keypad to enter or modify the name of the
method. Press to confirm.
Select H2O volume and use the numeric keypad to enter or modify the volume of
H2O . Press to confirm.
Select NaOH volume and use the numeric keypad to enter or modify the volume of
NaOH . Press to confirm.
Select Pause and use the numeric keypad to enter or modify the time lapse
between the entry of reagents and the beginning of steam production. Press to
confirm.
Select Distillation time and use the numeric keypad to enter or modify the distillation
time (steam production time). Press to confirm.
Select Steam power and use the numeric keypad to enter or modify the steam power
during distillation (from 10 to 100%). Press to confirm.
Select Empty test-tube and choose from the two options available. Select automatic
residues aspiration if needed. Press to confirm.
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4.5. Set-up
Select Set-up from the "Main" menu.
Select Date and use the numeric keypad to enter or modify the date. Press to
confirm.
Select Time and use the numeric keypad to enter or modify the time. Press to
confirm.
Select Language and use the touch-screen to choose from the list of languages
available. Press to confirm..
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Select Frequency and use the touch-screen to select the frequency of the power
supply at the place of installation . Press to confirm.
Select Laboratory name and use the alphanumeric keypad to enter or modify the
name of the laboratory. Press to confirm.
The name of the laboratory will be printed on the report.
Select Type and choose from the options available: Standard / Compressed. Press
to confirm.
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Standard Compressed
VELP SCIENTIFICA VELP SCIENTIFICA
Distillator: UDK139 Distillator: UDK139
Software Version: 1.0.0 Software Version: 1.0.0
______________________ ______________________
Date: Date:
20/09/2010 20/09/2010
Time: Time:
14.49 15.00
Laboratory name: ID:
Velp Scientifica 5
Operator: Sample:
Paolo Milk
Q.ty sample:
ID: 5,0000ml
4 Notes:
Sample:
Milk ______________________
Q.ty sample:
5,0000ml
Method:
Test
H2O:
50ml
NaOH:
20ml
Pause:
00:00
Distill. Time:
03:00
Steam:
100%
Empty test tube:
Yes
Notes:
______________________
Select Display. Use the two sliding bars to adjust the contrast and brightness of the
display. Press to confirm.
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4.6. System
Select “System” from the main menu.
4.6.1. Check-up
Select Check-up from the "Main" menu.
To return to the “System” menu, press the arrow in the upper left corner.
The "Check-up" menu is used to fill/empty the hydraulic circuits of the reagents,
these checks can be carried automatically or manually at any time.
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It is also possible check the correct functioning of safety devices, level sensors and
the cooling water detector.
NOTE: it is fundamental that all the checks are carried out during installation in order
to fill the hydraulic circuits. Velp recommends the use of the automatic controls
during this phase.
Manual check-up
Select “Manual check-up” from the “Check-up” menu. The following window
appears:
To return to the “Check-up” menu press the arrow in the upper left corner.
Select Fill H2O circuit to fill the dilution water circuit.
Press to start filling.
The green flag on the right indicates that the operation was carried out correctly, a
red X indicates that the operation was not successful.
Select Empty test-tube to remove the reagents from the test tube.
Automatic check-up
Select “Automatic check-up” from the “Check-up” menu. The display shows:
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To return to the “Check-up” menu press the arrow in the upper left corner.
NOTE: if a check-up has failed identify the cause before repeating the operation.
Diagnosis
This option is used to check the correct functioning of safety devices, level sensors
and water detector.
Select the submenu Diagnosis, the display shows:
To return to the “Check-up” menu press the arrow in the upper left corner.
Select Check safety devices. The display shows:
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The green flag on the right indicates that the operation was carried out correctly, a
red X indicates that the operation was not successful.
It is also possible to check the correct functioning of the level sensors on the tubes
supplied with the instrument for loading reagents and discharging the overflow of
residues.
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Press the button Inlet tube NaOH. The display shows the following screen:
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Press to check the correct flow of cooling water in the hydraulic circuit.
The green flag on the right indicates that the operation was carried out correctly, a
red X indicates that the operation was not successful.
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4.6.2. Calibration
Select Calibration from the “System” menu.
NOTE: Make sure that the hydraulic circuits are filled before calibrating (see "Check-
up").
Press to begin the process. The instrument measures 50ml of diluting water.
Transfer the reagent (diluting water) to a graduated cylinder to measure the real
volume. Use the numeric keypad to enter the real volume, press confirm.
Repeat the procedure for the NaOH pump.
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NOTE: If you wish to double-check correct dosage after calibration, this should be
done during a normal work-cycle since during calibration a theoretical volume of
50ml only can be measured.
NOTE: The instrument is calibrated before leaving the factory therefore calibration
by the user is only necessary if one of the reagent pumps is replaced or if a different
concentration of NaOH is used.
4.6.3. Maintenance
Select “Maintenance” from the “System” menu.
Cleaning the NaOH tubes and reagent filters and replacing the test tube
connection.
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Select Cleaning of NaOH circuit from the “Maintenance” menu, the display shows:
To return to the "Maintenance" menu press the Maintenance arrow top left.
The following information is displayed:
- Maintenance frequency. Maintenance is recommended every 500 analyses;
- Analyses from last maintenance;
- Date of last maintenance (DD-MM-YYYY).
Maintenance is recommended every 500 analyses (1000 analyses in case of
replacing the test tube connection). After 500 analyses from the last maintenance
(1000 analyses in case of replacing the test tube connection), when the instrument is
turned on a prompt recommends that maintenance be carried out. If the operator
chooses to defer maintenance, the prompt is repeated after an additional 20
analyses. In that case the maintenance interval is updated too (e.g. from 500 to
520).
4.6.4. Service
Select Service from the "System" menu.
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5. Operating Controls
5.1. Safety devices, signals and warnings
5.1.1. Safety devices
The instrument is equipped with various safety devices that can prevent start-up or
interrupt a work-cycle to protect the operator and the instrument itself.
Test tube:
If the test tube is not correctly positioned analysis will not start when START is
pressed. An acoustic signal warns the operator of an error and the following warning
message appears on the display for a few seconds: “AL3. Insert test tube”.
If an attempt is made to remove the test tube during a work cycle an acoustic signal
warns of the danger, the above warning message appears and the work cycle is
interrupted.
Safety guard:
If the safety guard in front of the test tube is not closed analysis will not start when
START is pressed. An acoustic signal warns the operator of an error and the
following warning message appears on the display: "AL4. Close protection".
If the safety guard is opened during a work cycle an acoustic signal warns of the
danger, the above warning message appears and the instrument continues the work
cycle in progress.
Safety lever:
If the lever is not released, analysis will not start when START is pressed. An
acoustic signal warns the operator of an error and the following warning message
appears on the display:"AL5. Release lever".
If the lever is lowered accidentally during a work cycle, an acoustic signal warns of
the danger, the above warning message appears and the instrument continues the
work cycle in progress.
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Reserves
An automatic warning system notifies the operator of low reagent levels during
analysis. The external reagent tubes supplied with the unit are fitted with level
sensors. The level sensors should be connected to the “Reserve” contact of the
corresponding inlet connection on the rear panel of the unit.
If the level of reagent in the tank falls below the minimum, when Start is pressed from
the “Analysis” or “Check-up” menu, the display shows one or more of the following
messages:
NOTE: Check reagent levels using the "Check-up" menu, the instrument will indicate
if any of the reagents are in reserve (see chapter 4.6.1).
IMPORTANT
Do not remove the reagent tubes with level sensors from the tanks as this cause a
partial emptying of the tubes. When a reagent is in reserve the tank should be
topped-up rather than replaced in order to avoid emptying the tubes.
If a tank is replaced, fill the tubes as described in “Check-up" (Chapter 4.6.1).
Overfilling
The unit is fitted with a dedicated hydraulic circuit for the removal of distillation
residues which are conveyed to a tank for disposal according to the regulations in
force in the place of installation.
The residues removal tube with level sensor should be connected to OUTLET
Distillation Residues on the rear of the unit and the electric contact of the level
sensor to the corresponding “Full” contact .
If the level of waste inside the tank exceeds the threshold defined by the level
sensor, when Start is pressed in the "Analysis" or "Check-up" menu, the display
shows "AL9. Residues overflow”.
Empty or replace the residues tank.
It is possible to start the work-cycle even with the overflow alert active by pressing
Continue.
NOTE: Check the level of the overflow tank using the "Check-up" menu, the
instrument will report the overflow (see chapter 4.6.1).
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Warning messages
Preheating
When the instrument is turned on a yellow stripe at the top of every page of the
software warns the operator that preheating of the steam generator is in progress. If
Start is pressed for a work-cycle that requires the production of steam, the display
shows: "Preheating in progress".
The end of preheating is signaled by a beep and the yellow stripe at the top of the
display is replaced by a blue stripe. Press Start to start the work-cycle.
Check name and quantity of sample
If Save was not pressed after entering the analysis parameters for Single distillation
or Distillation in series, when Confirm is pressed the following prompt appears:
“Check Name/Q.ty of sample”. Press Continue.
Press Confirm to confirm the sample name and quantity previously entered followed
by Start to proceed with the analysis.
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5.1.4. Black-out
A power failure during analysis will result in the analysis in progress being lost. The
previously entered analysis parameters will be retained. When the electricity is
restored the unit will carry out preheating before starting analysis.
40
35 34'
WITH 100 ml OF WATER
2 AT 15°C IN THE TEST TUBE
30'
30
DISTILLATION TIME (min)
25
20
15
12'40''
11'30''
10
6'30''
5'30''
4'45'' 3'45''
5
5'45'' 3'
4'45''
4' 3'20'' 2'45''
0
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 110%
STEAM FLOW (%)
The UDK139 Semi-automatic Distillation Unit can produce 100ml of distillate in just 4
minutes (see graph). Steam production can be set from 10% to 100% in order to
perform fast or slow distillations.
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It is important to underline how the new titanium condenser keeps the temperature of
the distillate below the threshold value (35°C) indicated by the Kjeldahl method
without increasing the tap water flow rate (1l/min).
The titanium condenser is also highly efficiency at low temperatures. With a tap
water temperature of 21°C, a distillate temperature of 27°C is obtained using the
titanium condenser compared to 29.5°C using a conventional glass condenser.
The new titanium condenser reduces tap water consumption to a minimum. In fact
the high thermal exchange means that a tap water flow rate of 0.5 l/min is sufficient
for the analyses to be carried out correctly.
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6. Work cycle
The unit can perform different types of analysis:
Analysis
Devarda’s analysis
The steps involved for each method are shown below.
6.1. Analysis
1. Switch on the instrument using the ON/OFF switch on the rh side of the
instrument;
2. The instrument carries out preheating lasting 3 minutes;
3. Turn on the tap water;
4. Position the empty test tube;
5. Position the anti-skid disk on the flask stand;
6. Position the flask on the anti-skid disk;
7. Make sure that the distillate outlet tube is correctly positioned in the flask (it
should reach the bottom of the flask)
8. Carry out manual or automatic check-up;
9. Carry out one or more wash-downs;
10. Carry out one or more blank analyses;
11. Position the test tube containing the sample;
12. Select the analytical method required.
13. Enter the GLP data for the analysis (operator name, sample name, sample
quantity, distillation time);
14. Start analysis.
15. An acoustic signal indicates that the work cycle has terminated.
16. Remove the test tube and replace it with a new sample. If distillation series has
finished, place an empty test tube in the unit.
17. Press to start a new analysis.
7. End-of-work operations
Before turning the instrument off at the end of the working day carry out a wash-
down from the “Analysis” menu;
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8. Maintenance
The instrument is fitted with a cycle counter that alerts the operator through
messages on the display when routine/extraordinary maintenance is required.
The front panel (service door) of the instrument opens fully to allow easy and safe
access to the internal parts in order to carry out the following operations:
Simple and immediate inspection of internal parts
Remove and clean the drip tray
Remove the test tube connection
Servicing the instrument (routine and extraordinary maintenance) is very important to
keep the unit in good working order and to extend its life time. Follow the instructions
given below.
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Periodic maintenance
Replace fuses
Clean the condenser
Clean the inside of the safety guard
These tubes must be kept full at all times. When the sodium hydroxide solution
comes into contact with air, crystals are formed which obstruct the tubes and
jeopardize the correct functioning of the internal parts.
The tubes must be cleaned as part of extraordinary maintenance operations as
follows:
The unit is fitted with 4 filters to remove particles, sediment or any other foreign
bodies from the tap water and reagents.
NOTE: Disconnect the unit from the electric power supply and water supply
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The filters are found on the tap water inlet and on the reagent inlets:
- Tap water inlet: remove the cooling water tube from the unit and pull the filter out
using small pincers. Clean the filter under running water or using compressed air
- Reagent inlets: the three reagent tubes with level sensors are fitted with filters
located at the lower extremity. Wearing protective gloves remove the filters by pulling
outwards. Open the filters by means of the ridge and wash under running water.
During this operation the tubes may empty. After repositioning the filters repeat the
manual filling of tubes (see chapter 4.6.1).
The test-tube connection must be replaced when it loses its elasticity, when it looks
deformed and does not provide a perfect seal, or after 500 analyses.
For easier removal carry out a wash-down cycle. The splash head can reach high
temperatures therefore take care when handling. Open the safety guard.
Remove the test tube, the test tube connection and the safety guard. The following
tips will facilitate removal:
1. Wearing a protective glove, grip the splash guard and rotate it whilst pulling
downwards.
2. Use a pointed tool or small screwdriver to exert leverage through the special
window accessed from the inside of the service door.
Proceed with replacement. The new test tube connection will be easily fitted if it is
soaked in warm water beforehand.
The splash guard should be cleaned using soft cloth dampened with warm water. Do
not use abrasive detergents or cleaning agents containing solvents.
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When moving the instrument always use the special handles on the side of the
instrument.
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10. Accessories
Description: Code
Test tube Ø 80x300 mm for alcohol determination A00001083
Test tube Ø 48x260 mm, 300 ml A00001088
Test tube diam. 42x300mm, 250ml, 3 pcs/box A00000144
Test tube diam. 26x300mm, 100ml, 6 pcs/box A00000146
Test tube Ø 50x300mm, 400ml A00000185
Spacer for test tube Ø 48x260 mm A00000206
Test tube connection Ø 26 mm, Ø 48 mm
and 500 ml Kjeldahl balloon A00000043
Printer (connection cable included) A00001009
Printer Adapter USB-RS232 A00000195
IQ/OQ/PQ Manual UDK 139 A00000204
Waterproof mouse A00000215
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The above mentioned spare parts can be easily replaced by the operator. For other
spare parts (and for the complete list) please contact Velp Scientifica Srl’s nearest
Service Centre.
* Replace the fuses only when necessary, i.e. if the unit doesn’t turn on and the
mains switch does not light up. The fuses must only be replaced by qualified
personnel and only with fuses supplied by Velp Scientifica Srl.
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GENERAL
Power supply (AC) V/Hz 230~(+/- 10%)/50-60
Total electric power W 2200
Heating element power W 2000
Dimensions (W x H x D) mm 385x780x416
inch 15.2x30.7x16.4
Weight kg 26
lb 57.3
Display LCD graphic touch-screen
Languages UK – I – E – F – RUS - CN
Reserves Low reagent level signal
Overfilling Residues tank
Overflow signal
Pollution degree 2
Overvoltage category II
Max. Altitude m 4000
Max. Admitted humidity % Max 85
Storage temperature range °C +5 ….+60
°F +41 …+140
Ambient temperature range °C +5 …..+40
°F +41 …+104
Fuses A 2x15A 250V
Sound Level dBA 35
PERFORMANCES
Nitrogen amount mgN 0.1 - 200
Reproducibility % ≤1
Recovery rate % 99.5
Detection limit mgN 0.1
Distilling time min:sec 4:00 (for 100ml of
distillate at 100%
steam output)
CONSUMPTION
Cooling water (during analysis only) l/1’ 1 to 30°C
from 0.5 to 15°C
Deionised water for Steam generator ml/1’ 50 at max. flow
(Steam 100%)
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ANALYTICAL METHODS
Standard methods N° 10
ANALYSIS DATA
The following parameters can be set for each analysis:
Method
Operator name
Sample name
Sample quantity g o ml
Notes
INTERFACES
N°2 USB for printer, USB pen drive, mouse
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N° Descrizione
1 Fuse 6.3x32 15A
2 ON/OFF switch with led
3 Operatingl thermostat
4 Safety thermostat
5 Steam generator
6 Door open trip switch
7 Steam generator
8 Steam electrovalve
9 Discharge electrovalve
10 Boiler outlet electrovalve
11 Distillation residues discharge electrovalve
12 Water inlet electrovalve
13 Electronic board for warning signals
14 Display board
15 Electronic board for reserve signals
16 Water flow detector
17 Safety microswitch for safety guard
18 Safety lever
19 Safety microswitch for test tube
20 Main board
21 Sodium hydroxide pump
22 Dilution water pump
23 Steam power pump
24 Cable 2 pole
25 Cable for PC board
26 Flat cable10-pole
27 Flat riserve
28 Vessel discharge electrovalve
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EPDM = Butyl
MQ/MVQ = Silicone
PTFE = Teflon
LLDPE = Low density polyethylene
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15. Warranty
The unit is guaranteed against production defects for 25 months from our invoice
date.
Warranty claims can be accepted only if the system has been installed and used as
specified on the manual and carried out by qualified service personnel as appointed
by VELP Scientifica.
Exclusions:
The guarantee will be considered null and void for faults resulting from:
- inexperience and carelessness of the operator
- repairs, maintenance or replacement of parts carried out by personnel or
Companies not authorized by the manufacturer
- use of the instrument that does not comply to the instructions/recommendations
given in the present operating manual
- use of non-original spare parts.
16. Suggestions
We will be pleased to receive any comments and/or suggestions that will help us to
improve this operating manual.
e-mail: service@velp.it
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Sample range
2 - 150 mg of organic Nitrogen
15 - 1000 mg of proteins
Nitrogen standard
If the control of only the distillation steps is required, ammonium salts (chloride,
sulphate) are used. For example:
153 mg of ammonium chloride reagent grade are dissolved to 100.0 ml with
ammonia free water.
25.0 ml of this solution and 10 ml of 1 N sulfuric acid free of ammonia are diluted to
1000 ml with ammonia free water.
1 ml of the final solution contains 0.01 mg of N - NH3.
This solution is very diluted (1 mg of N-NH3 corresponds to 100 ml) and therefore
can be useful to use less diluted solutions. For example bringing the indicated
amounts to 100 ml (instead of 1000 ml) one obtains a final content of 0.1 mg
N-NH3 per ml of standard solution.
When the control of oxidative digestion is also required, pure Nitrogen containing
chemicals are used previously desiccated to constant weight.
- Glycine (glycocoll or aminoacetic acid) 18.66% Nitrogen
- Sulfamic acid (amidosulfonic acid) 14.43% Nitrogen
- Acetanilide 10.36% Nitrogen
- Cystine 11.66% Nitrogen
- Nicotinic acid 11.38% Nitrogen
For the analysis of inorganic nitric or ammonia Nitrogen the following standards can
be used:
- Ammonium dihydrogen phosphate (NH4H2PO4) 12.15% Nitrogen
- Potassium nitrate (KNO3) 13.85% Nitrogen
Digestion acid
Concentrated sulphuric acid (H2SO4) is used, reagent or technical grade, with a
reduced Nitrogen content (ammonia and nitrate), 98%, d 1.84 at 20 °C.
This acid is also specified "for Kjeldahl analysis". It is possible to use also
concentrated sulphuric acid not specified "for Kjeldahl", but in this case a regular
control by blanks is recommended.
There are recipes for the preparation of catalyst containing (Copper and Selenium)
sulphuric acid. For example: 10 g of cupric sulphate (CuSO 4 5 H2O) are dissolved
by 500 ml of ammonia free water and then 500 ml of concentrated sulphuric acid are
slowly added while slowly shaking (do not add the water to acid to avoid dangerous
splashing). As an alternative, 2 g of cupric sulphate (CuSO 4 5 H2O), 2 g of
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Selenium dioxide (SeO2) and 100 g of anhydrous Sodium sulphate (Na2SO4) are
dissolved by 500 ml of ammonia free water and then 500 ml of concentrated
sulphuric acid are added.
Ammonia free distilled water for dilutions
Add 0.1 ml of concentrated sulphuric acid (H2SO4) to one liter of distilled water and
distill again.
It is also possible to use deionized water with very low conductivity, obtained by a
mixed bed of strong anionic and cationic resins, and tested for the absence of
ammonia and of Nitrogen containing organic matter (biofouling).
A complete equipment for the production of ammonia free distilled water is shown in
the following scheme:
Sample to be analyzed
Liquid, semisolid or solid samples can be submitted to analysis. If a liquid is
measured by volume the result will be referred to volume and not to weight if the
density is different from 1.
When the result is to be referred to dry weight, solid or semisolid samples containing
water must be desiccated to constant weight. Grinding of samples is aimed to obtain
an easier digestion but is mostly aimed to homogenize the matter in order to obtain
significant results. Weighing accuracy is 0.1 mg.
To allow a quantitative transfer of a solid or semisolid sample into the digestion tube,
it is recommended to use weighing boxes made with Nitrogen free parchment paper
(Code CM0486000). These boxes will be introduced with the sample into the tubes
and digested without modifying the result. Sample dimensions are related to Nitrogen
content and must give at least 10-15 mg of ammonia Nitrogen. If a sample is
evaluated as poorly homogeneous, amounts larger than normal (e.g. 3-4 g) are to be
analyzed.
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Catalysts
Mercury is considered the best catalyst for Kjeldahl oxidative digestion, but its toxicity
for man and the environment brought to dismiss its use. The same can be said for
Selenium. To-day Copper sulphate (CuSO4 • 5 H2O) with lower environmental
damage is commonly used. It is previously mixed with anhydrous Potassium
sulphate (K2SO4) with a weight ratio of 9 K2SO4 to 1 CuSO4 • 5 H2O. Each sample is
added with 7.5 g of this mixture (Missouri catalyst). There are commercially available
tablets containing anhydrous Potassium sulphate and different types of catalysts in
pre-dosed amounts, easily used (for example packing of 1000 tablets by Velp
Scientifica).
Other additions
A rise of boiling temperature of the digestion acid is obtained by adding mineral salts,
mostly Potassium sulphate (K2SO4). The use of Hydrogen peroxide (H2O2)
35% (130 volumes) is aimed to assure a complete mineralization of samples.
This reagent is to be added to the cold mixture (sample + acid) before digestion in
order to avoid violent reaction and dangerous splashing.
Do not ever start heating if no acid is still added, because Hydrogen peroxide in
contact with a sample can give rise to explosions.
Other reagents
An alkaline reaction of digested samples, before distillation, is obtained by adding a
concentrated (32-35%) solution of Sodium hydroxide (NaOH), ammonia free (50 ml
of NaOH for 7 ml of concentrated H2SO4).
1 ml of concentrated sulfuric acid 98% d. 1.84 contains 36.6 milliequivalents of acid.
1 ml of sodium hydroxide solution 32% w/w d.1.35 contains 10.8 milliequivalents of
alkali. Thus 1 ml of concentrated sulphuric acid is stoichiometrically neutralized by
3.39 ml of sodium hydroxide 32% solution. The distillation of ammonia requires a
highly alkaline environment which means that ammonia is completely in the so called
"free" form. This is obtained adding a 100% excess of alkali.
We suggest to use 50 ml of sodium hydroxide 32% solution for a sample digested
with 7 ml of concentrated sulphuric acid (70 ml for 10 ml or 100 ml for 15 ml acid).
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Steam distilled ammonia can be collected with the condensate from the water cooled
condenser in two different ways:
a) in a classical solution of sulphuric acid of known titre and following back-titration.
b) more recently, by a solution 4% of boric acid (H 3BO3). Boric acid is practically un-
dissociated and allows direct titration of alkali (ammonia) by strong acids of known
titre.
Indicator solutions
A volume of 125-130 ml of solution to be titrated requires 10 drops about of indicator
solution.
a) for a back-titration of sulphuric acid with Sodium hydroxide: 20 - 30 mg of methyl
red in 100 ml of water; colour change from red to yellow at pH 4.9.
Or: 100 mg of bromocresol green and 30 mg of methyl red in 100 ml ethyl alcohol
96%; colour change from red to green at pH 4.5.
b) titration by sulphuric or hydrochloric acid of ammonia absorbed by boric acid
solution.
Tashiro's indicator: 0.6 g of methyl red are dissolved by 50 ml of 95% ethyl alcohol
and then added to a methylene blue solution (0.1 g in 50 ml of distilled water).
The colour is green in alkaline range and gray to pink (pH 4.9) in acid medium to red
with an excess of acid.
Potentiometric titration
It can be performed by using N/50 HCl and an end point of pH 4.7. The low
dissociation of boric acid allows direct titration of alkali (ammonia).
Colorimetric determination
Besides titration, ammonia nitrogen determination can be performed by colorimetric
methods, for example:
1. Method 417 B. Nesslerization or Method 417 C. Phenate: Standard Methods for
the Examination of Water and Wastewater. 16th Edition.
APHA-AWWA-WPCF. Washington D.C. 1985.
2. Method D 1426. Ammonia nitrogen. Book of Standards ASTM. Part. 23.
Water and Atmospheric Analysis. Philadelphia. 1983.
3. Analytical kits for water. Available on request.
In any case the ratio between weight or volume of sample and volume of distillate
used for ammonia determination must be taken into account.
Calculation
It is commonly agreed that protein content is obtained multiplying by 6.25 the weight
of Nitrogen obtained by the Kjeldahl method. This corresponds to consider all
proteins as composed by 16% Nitrogen.
As a matter of fact protein composition ranges from 15 to 18% Nitrogen.
This accounts for other factors, sometimes used, different from 6.25, generally lower.
AOAC suggests for specific products the following factors: 5.18 for almonds; 5.30 for
coconuts and other tree nuts, 5.46 for peanuts and Brasil nuts; 5.70 for wheat flour;
6.38 for milk and dairy products (official Methods of Analysis (1984). Association of
Official Analytical Chemists. Arlington, VA-USA).
FAO-WHO (1973) propose factor 5.70 for wheat meal and soy.
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Definitions
Total Kjeldahl nitrogen (TKN) is defined as the sum of ammonia nitrogen and organic
nitrogen converted to ammonium sulphate in the mineralization conditions adopted
by the method. Organic Kjeldahl nitrogen is given by the difference between the
value of total Kjeldahl nitrogen and the value of ammonia nitrogen.
If a direct determination is wanted, ammonia nitrogen is to be removed from the
sample before mineralization.
Digestion procedure
The weighed sample is quantitatively transferred into a digestion tube (1 g about)
and 7-15 ml of digestion acid and then, after placing on the digester two heat shields
which make the heating of the digestion tube more homogeneous, heating is started
(420°C) and continued till white fumes of Sulphur trioxide (SO3) are produced (20 -
30 minutes).
The apparatus should be under a hood or with a disposing mean for fumes in
operation with neutralization by concentrated solutions of strong alkalies
(e.g. SMS Scrubber Velp Scientifica, Code F307C0199). Sulphur trioxide fumes are
strongly irritant and aggressive for mucous membranes at concentrations as low as 1
ppm. If the liquid is not clear, one drop of Hydrogen peroxide solution (H 2O2 30% 130
voll.) is added and boiling is continued for 10 minutes.
When digestion is finished the tubes are left to cool. Cooling time can be shortened
by blowing air with a fan. When the tubes are cool, 50 ml of ammonia free distilled
water are added and the tubes are shaken.
NOTE!
It’s strongly recommended NOT to introduce in the test tubes, during sample
digestion or distillation, boil-reducers (small glass balls, small pieces of
ceramic material) which could damage the distillator.
Distillation procedure
A cool digestion tube is placed into position in the steam distilling unit.
The same is done with an empty Erlenmeyer flask for distillate collection.
The automatic distillation program is set for the addition of boric acid 4% solution
(usually 25 ml) to the 250 ml Erlenmeyer flask for distillate collection; of an adequate
volume of sodium hydroxide 32% solution for neutralization and alkalinisation (from
50 to 100 ml) of the sample and of distilled or deionized water for its dilution (usually
50 ml). The end of the silicone tube from the condenser must be under the surface of
boric acid solution to avoid ammonia losses. Usually 100 ml of distillate are collected.
NOTE!
It’s strongly recommended NOT to use the distillation residues aspiration if the
sample to be distillate contains the solid residues, to avoid damages to the
distillation unit.
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This method ISN’T suitable for sample materials having N-N or N-O bonds.
Equipment:
- digester DK 20/26 code F30100185, or DK 42/26 code F30100186
- glass test tubes diam. 26mm x 300 mm, code A00001091
- adapter A00000043
Procedure:
1) Sample: weigh 10-30mg of sample, nitrogen free weighing boats can be used,
code CM0486000, and introduce it into the test tube.
Use for analysis an amount of sample which needs 3-10ml of 0.01 or 0.02N HCl
(containing 0.85-1.70mg of nitrogen).
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2) Reagents for digestion: for each sample add in the test tube:
1 catalyst tablets ST (code CT0006609) (containing Selenium as catalyst)
2.0ml of sulphuric acid concentrated, 96-98%
Normally, the sample weight to analyse is 15mg about; add 0.1ml of acid
more for every 10mg of dried organic substance >15mg.
Halve the amount of reagents above, if the sample is < 7mg, except when
using the weighing boats.
Program:
Select a method with the following volumes of the reagents:
dilution water, 10 ml
Boric acid, 25 ml
Sodium hydroxide, 35% (W/V), 10 ml
Steam 100%
Distillation time: 4 min
Titrate the distillate by HCl or H2SO4 0,01 N or 0,02 N programming an end point
titration to pH 4.7.
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F Place the digestion tube in the digestion unit: i.e. DK6 or DK20
M Titrate distillate
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Factor: 6.38
Addition of reagents:
dilution water= 50ml
H3BO3= 30ml
NaOH= 70 ml
Titrant: HCl 0.1N
Distillation time= 4 min
Steam power= 100%
Press the button starting distillation cycle.
Factor: 5.18
Addition of reagents:
dilution water= 50ml
H3BO3= 30ml
NaOH= 50 ml
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Procedure
1 Sample: grind the sample by a suitable device. Weigh 0.5-0.8g of sample with an
accuracy of 0.1mg.
2 Reagents for digestion: for each sample add in the test tube:
2 catalyst tablets CM (code CT0006650)
12 ml concentrated sulphuric acid (96-98%)
2 antifoam tablets S (code CT0006600)
factor: 5.30
Addition of reagents:
dilution water= 50ml
H3BO3= 30ml
NaOH= 50 ml
Procedure
1 Sample: grind the sample by a suitable device. Weigh 0.5-0.8g of sample with an
accuracy of 0.1mg.
2 Reagents for digestion: for each sample add in the test tube:
2 catalyst tablets CM (code CT0006650)
12 ml concentrated sulphuric acid (96-98%)
2 antifoam tablets S (code CT0006600)
factor: 5.46
Addition of reagents:
dilution water=50ml
H3BO3=30ml
NaOH=50 ml
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Among components of soluble extract of beer there are proteins and aminoacids.
Soluble extractives represent from 3% to 12% of the weight of beer.
Procedure:
Addition of reagents:
dilution water = 50 ml
H3BO3 = 30 ml
NaOH = 50 ml
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Procedure
1) Sample: 1 g of malt finely grinded and sieved to 2 mm, previously dried in oven at
105°C up to constant weight, accurately weighed and transferred quantitatively in a
test tube.
2) Reagents for digestion: for each sample add in the test tube:
2 catalyst tablets ST (code CT0006609)
12ml sulphuric acid concentrated (96%)
3) Digestion: set on the digester the following temperature ramps:
20 min at 220°C and then 40 min at 420 °C.
4) Cooling: let cool the test tubes to 50-60°C.
5) Distillation-titration: place in position the test tube with the digested sample in
the unit UDK 139.
factor: 6.25
Addition of reagents:
dilution water=50ml
H3BO3=30ml
NaOH=50 ml
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Procedure
factor: 6.25
Addition of reagents:
dilution water=50ml
H3BO3=30ml
NaOH=50 ml
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Procedure
factor: 5.70
Addition of reagents:
dilution water=50ml
H3BO3=30ml
NaOH=50 ml
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Procedure
factor: 6.25
Addition of reagents:
dilution water=50ml
H3BO3=30ml
NaOH=50 ml
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Procedure
Addition of reagents:
dilution water=50ml
H3BO3=30ml
NaOH=50 ml
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Procedure
factor: 6.25
Addition of reagents:
dilution water=50ml
H3BO3=30ml
NaOH=60 ml
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Procedure
1) Sample: cut the sample by a pair of scissors to a length of 2-3 cm about. Dry the
sample and finally grind by a suitable device. Weigh 1g of sample with an accuracy
of 2mg.
2) Reagents for digestion: for each sample add in the test tube:
2 catalyst tablets ST (code CT0006609)
12 ml concentrated sulphuric acid (96-98%)
Addition of reagents:
dilution water= 50ml
H3BO3= 30ml
NaOH= 50 ml
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Procedure
Addition of reagents:
dilution water= 75ml
H3BO3= 30ml
NaOH= 50 ml
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The protein content in fresh bovine meat is about 20% (3% of proteic nitrogen about).
Dried salted meats contain about 35% proteins, while salted meat show values
between11 and 17%, depending on fat and water content.
Procedure
1) Sample: 1 g about of ground product, accurately weighed (60 mg about of proteic
nitrogen for fresh meat, interval 40÷100) and quantitatively transferred in the test
tube.
2) Reagents for digestion: for each sample add in the test tube one of the following
catalysts:
factor: 6.25
reagents addition:
dilution water= 50ml
H3BO3= 30ml
NaOH= 70 ml
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5) Distillation-titration: place in position the test tube with digested sample in the
unit UDK 139.
factor: 5.7
Reagents addition:
dilution water= 75ml
H3BO3= 30ml
NaOH= 50 ml
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Procedure
1) Sample: grind, if necessary, and make the sample homogeneous by suitable
devices; weigh 0.5-0.7 g of sample with an accuracy 0.1mg.
2) Reagents for digestion: for each sample add in the test tube:
2 catalyst tablets CM (code CT0006650)
12 ml concentrated sulphuric acid (96-98%)
5) Distillation-titration: place in position the test tube with digested sample in the
unit UDK 139.
factor: 6.25
Reagents addition:
dilution water=75ml
H3BO3=30ml
NaOH=50 ml
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Procedure
1) Sample: 2g of sample weighed with an accuracy of 0.1mg after homogenizing by
suitable device.
2) Reagents for digestion: for each sample add in the test tube:
2 catalyst tablets CM (code CT0006650)
12 ml concentrated sulphuric acid (96-98%)
factor: 6.25
reagents addition:
dilution water= 50ml
H3BO3= 30ml
NaOH= 50 ml
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Procedure
1) Sample: weigh 1g of sample with an accuracy of 0.1mg (2g for molasses with
the same accuracy).
2) Reagents for digestion: for each sample add in the test tube:
5) Distillation-titration: place in position the test tube with digested sample in the
unit UDK 139.
factor: 6.25
Reagents addition:
dilution water= 75ml
H3BO3= 30ml
NaOH= 50 ml
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Procedure
1) Sample: break the pasta in small pieces by hands or suitable device and mix well.
Grind finally the sample by a suitable device. Weigh 1g of sample with an accuracy
of 0.1mg.
2) Reagents for digestion: for each sample add in the test tube:
Addition of reagents:
dilution water= 50ml
H3BO3= 30ml
NaOH= 50 ml
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Procedure
1) Sample: break the pasta in small pieces by hands or suitable device and mix well.
Grind finally the sample by suitable device. Weigh 1g of sample with an accuracy of
0.1mg.
2) Reagents for digestion: for each sample add in the test tube:
Reagents addition:
dilution water= 50ml
H3BO3= 30ml
NaOH= 50 ml
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Procedure
1) Sample: mince and homogenize the sample by suitable devices, then weigh 0.5-
1.5 g in the test tube.
2) Reagents for digestion: for each sample add in the test tube:
5) Distillation-titration: place in position the test tube with digested sample in the
unit UDK 139.
factor: 6.25
Reagents addition:
dilution water=75ml
H3BO3=30ml
NaOH=50 ml
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Procedure
1) Sample: 10g of ground dried sample.
2) Reagents for digestion: for each sample add in the test tube:
5) Distillation-titration: place in position the test tube with digested sample in the
unit UDK 139.
factor: 6.25
Reagents addition:
dilution water=50ml
H3BO3=30ml
NaOH=50 ml
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Procedure
1) Sample: homogenize the sample by shaking before analysis. Weigh 1g of sample
with an accuracy of 0.1 mg.
2) Reagents for digestion: for each sample add in the test tube:
factor: 0.00
Reagents addition:
dilution water= 70ml
H3BO3= 30ml
NaOH= 70 ml
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1) Sample: RUBBER: the sample is cut in small pieces and then ground.
0,5 g of sample accurately weighed are used for the analysis.
SAN: cut in small pieces the sample . Grind it. Pellets of 1x3 mm can be directly
analysed. Weigh 0.50 g of sample with an accuracy of 2 mg.
ABS: grind the sample. Weigh 0.50g with an accuracy of 2 mg. Pellets of 1x3 mm
can be directly analysed.
2) Reagents for digestion:
factor: 6.25
Reagents addition:
dilution water= 50ml
H3BO3=30ml
NaOH (40% w/v) = 60 ml
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Procedure
1) Sample: the sample is ground in order to obtain a powder very fine and
homogeneous .
1g of sample accurately weighed is quantitatively transferred in a test tube.
2) Reagents for digestion. for each sample add in the test tube:
2 catalyst tablets CM (code CT0006650)
12ml concentrated sulphuric acid (96-98%)
after the addition of reagents shake to wet the sample.
3) Digestion: 60 min at 420 °C.
4) Cooling: let cool the test tubes to 50-60 °C.
5) Distillation-titration: place in position the test tube with digested sample in the
unit UDK 139.
factor: 0.00
Addition of reagents:
dilution water= 50ml
H3BO3= 30ml
NaOH= 50 ml
The urea content of the sample is calculated considering that the nitrogen content of
urea is 46.65%.
The quantity of distilled ammonia from 0.1g of urea requires 16.64ml of 0.2N HCl to
be titrated.
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Procedure
2) Reagents for digestion: for each sample add in the test tube:
2 catalyst tablets CM (code CT0006650)
10 ml concentrated sulphuric acid (96-98%)
factor: 0.00
Addition of reagents:
dilution water = 50 ml
H3BO3 = 30 ml
NaOH = 50 ml
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A soil of good fertility contains 2-3% of organic matter mainly humus which is
composed by 4 - 6% of nitrogen.
There is also some ammonia nitrogen (some ppm) which is to be determined
separately and substracted from the value of Kjeldahl’s nitrogen obtained,if organic
nitrogen is needed.
Procedure
1) Sample: 1 g about of air dried soil, sieved to 2 mm (3÷12 mg of organic nitrogen),
dried at 105 °C up to constant weight, accurately weighed and quantitatively
transferred in a test tube.
2) Reagents for digestion:
2 catalyst tablets ST (code CT0006609)
12 ml concentrated sulphuric acid (96-98%).
factor: 0.00
Addition of reagents:
dilution water = 50 ml
H3BO3 = 30 ml
NaOH = 50 ml
To avoid damage to the distillator it’s strongly recommended to NOT use the
“removal of distillation residues” function.
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3) Digestion
Heat at 200 °C for some minutes to let the foam develop, then go to 420 °C for 30
minutes.
4) Cooling
Let cool test tubes to 50-60 °C
5) Distillation-titration: place in position the test tube with the digested sample in
the unit UDK 139.
factor: 5.60
Addition of reagents:
dilution water= 50ml
H3BO3= 30ml
NaOH= 50 ml
References:
TAPPI Standard T418 05-61. Organic Nitrogen in Paper, modified by reducing to the
half the quantity of mercury catalyst.
TAPPI Standards and Suggested Methods. Technical Association of the Pulp and
Paper Industry. Atlanta, Georgia, USA.
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3) Digestion
Heat at 200 °C for some minutes to let the foam develop, then increase the
temperature to 420 °C for 30 minutes
4) Cooling
Let cool test tubes to 50-60 °C
5) Distillation-titration: place in position the test tube with digested sample in the
unit UDK 139.
factor: 6.30
Addition of reagents:
dilution water= 50ml
H3BO3= 30ml
NaOH= 50 ml
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The final use of sludges from municipal wastewater treatment plants should be on
agricultural land for the recovery of useful nutrients. This is suggested also by the
Council of European Economic Community (EEC Directive 86/278) related to the
agricultural use of sludges from wastewater treatment if the level of contained toxic
elements (Cd, Cu, Ni, Pb, Zn, Cr, Hg) is not too high.
The total nitrogen content ranges from 2,2 to 4,2%, dry matter, and is represented by
ammonia, nitrite, nitrate, urea and organic nitrogen.
The method operates first a reduction of nitrite and nitrate to ammonia with metallic
chromium in acid solution and then the digestion of organic nitrogen to ammonia with
concentrated sulphuric acid and catalysts.
Finally ammonia is steam distilled and titrated.
Procedure
1) Sample: about 0,5 g of sludge dried at 105 °C up to constant weight.
(10 - 20 mg of N) or a corresponding amount of wet sludge, accurately weighed and
quantitatively transferred in a test tube.
2) Reagents for the reduction: for each sample add in the test tube:
0,5 g chromium powder (Cr)
20 ml hydrochloric acid 7% about (HCl) (200 ml of concentrated acid, 36% , to 1 liter
by ammonia free distilled water).
3) Riduction: let reaction run at room temperature for 5 min, shaking at intervals.
Heat to starting boiling for 4 minutes and let cool.
4) Reagents for digestion: for each sample add in the test tube:
2 catalyst tablets ST (code CT0006609)
10 ml concentrated sulphuric acid (96-98%)
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Steam distillation is a method to determine the alcoholic strength in wine, musts and
spirits: the distillate obtained is an ethanol – water mixture and, using a
measurement of density by a pycnometer and expressing the results through the
official tables, the alcoholic strength can be calculated.
3) Distillation
Select the mode “analysis without titration” and set a “customizable method” with the
following analytical parameters:
H2O (dilution water): 0 ml
Steam Power: 100%
NaOH (32%): 0 ml
Distillation Time: 5 minutes *
H3BO3 (4% with indicators): 0 ml
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Collect the distillate in the 200 ml graduated flask used to measure the wine quantity.
*set a distillation time to obtain a maximum of 200 ml of distillate. After the distillation,
position the receiving flask in the thermostat for about 15 min. and finally bring up to
volume (200 ml) using distilled water at 20 °C.
Where:
4. Use the density table of the official method to express the results:
for wine: OIV method - MA - AS312 - 01A
for spirits: Recommendation n°22 of the International Legal Metrology
Organization suggested by Reg. EC 2870/2000
5. Take care during the entire procedure: avoid fat from fingertips, temperature
changes when holding the pycnometer and air bubbles in it.
Reference:
For wine: Official analytical method OIV - MA - AS312 - 01A - Alcoholic strength by
volume
For spirits: COMMISSION REGULATION (EC) N° 2870/2000
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Procedure
1) sample: introduce into a test tube a 1 g soya sample finely grinded, add 0,20 g of
urea and 150 ml of distilled water.
Close immediately the test tube.
2) Incubation: shake the closet test tube and bring to 30 °C
(water bath). Allow the enzymatic reaction develop for 60 min, shaking at intervals.
3) Distillation:
analytical parameters:
4) Titration: titrate the residual acid in the flask by an alkalyne solution of known titre
and a suitable indicator (eg. Sodium hydroxide 0,1 N and methyl red).
5) Computation: the result is expressed as milliequivalents of ammonia produced
from urea per each gram of soyabean:
mlHCl0,1N neutralized
meq NH3
soya weight g x 10
6) Note: a strong foaming can develop during distillation, particularly with poorly
roasted soyabeans. Control distillation and if necessary stop it at intervals.
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Procedure
1) Reagents:
For the steam generator use distilled or deionised water boiled for some minutes in
order to eliminate the carbon dioxide. Use the same kind of water to dilute the
sample and for the distillate collecting flask.
2) Sample:
weigh 20g of sample by the VELP weighing boats and introduce in the test tube. The
use of the weighing boats avoids errors during the sample weighing, permitting to
transfer completely the sample to the test tube for the analysis.
Afterwards introduce in the test tube containing the sample 0.1g of tartaric acid and
then place in the distillator the test tube.
3) Distillation:
analytical parameters:
H2O = 50ml (distilled or deionized and boiled). NaOH = 0ml. H 3BO3 = 0ml.
Take off the distillate collecting tube from the condenser and place a new silicon tube
in the same position.
Place in position on the mobile round stand of the distillator an Erlenmeyer flask
(250ml) containing 40ml of deionised or distilled water boiled for some minutes. Be
sure that the end of the silicon tube, which is connected to the condenser, is
completely dipped in the water.
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5) Computation:
the sample volatile acidity is expressed as acetic acid in 100g of sample; 1ml of
NaOH 0.1N corresponds to g 0.006 of acetic acid:
NOTE: at the end of the analyses, perform 3 washing cycles of the distillator.
Introduce in the test tube 150-200ml of distilled or deionised water and set for each
washing cycle 5 min for the distillation time. The aim is the complete removal of
traces of sample from the glass splash-head.
References:
- Commission Reg. (EEC) No 1764/86, “Minimum quality requirements for tomato-
based products eligible for production aid”.
- SSICA-Stazione Sperimentale per l’Industria delle Conserve Alimentari-Parma-Italy,
monography “The tomato”, pag. 156 “Quality control of the tomato preserves” (Italian
language)
- Books of Food Chemistry, R. Giuliano and M.L. Stein, Bulzoni Ed.-Roma-Italy, 5°
vol. ALIMENTARY PRESERVES, pag. 119 “Analyses of the tomato preserves”
(Italian language).
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Reagents
hydrochloric acid (20 = 1.18-1.19 g/ml), analytical purity, diluted 1/4 (v/v)
Procedure
Bring the sample to room temperature. The dissolved carbon dioxide is removed by
stirring the sample or by using an ultra-sonic bath.
As an alternative: pour about 50ml of wine in a vacuum flask; stir and create vacuum at
the same time using a pump; stirring must take 1 or 2 minutes.
2) Distillation:
pour in a test tube 20ml of wine freed from the carbon dioxide.
Add about 0.5g of tartaric acid (used to make free the salified volatile acids which, in the
international methods, must be included in the volatile acidity) and place the test tube in its
site in the distillator.
Analytical parameters:
H2O = 0ml. NaOH = 0ml. H3BO3 = 0ml.
Take off the tube used to collect the distillate from the end of the condenser and
place a new silicon tube.
Place in position on the round stand of the distillator an empty Erlenmeyer flask and
collect at least 250ml of distillate.
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3) Titration:
4) Results:
- the volatile acidity expressed as milli-equivalents per liter, with 1 decimal, is:
- the volatile acidity expressed as grams of acetic acid per liter with 2 decimals , is:
inside the first 250ml of distillate is included also 96% of the sorbic acid present; for this
reason it is necessary to subtract its acidity from the volatile acidity considering that
100mg of sorbic acid correspond to an acidity of 0.89 milli-equivalents or to 0.053g of
acetic acid, knowing the amount of sorbic acid (mg/l) determined separately.
6) Determination of the salycilic acid present in the distillate of the volatile acidity:
After the determination of the volatile acidity and after the correction for the sulphur
dioxide, the presence of salycilic acid is revealed, after the addition of acid, by the
presence of a violet colour forming after addition of an iron III salt.The determination of the
salycilic acid ,present in the distillate of the volatile acidity, is to be performed in a second
distillate having the same volume of the distillate used for the dosage of the volatile
acidity.
In such a distillate the salycilic acid is determined by a comparative colorimetric method. It
is then subtracted from the distillate acidity.
a) Reagents:
- solution of ammonic ferric sulphate Fe2(SO4)3 x (NH4)2 SO4 x 24 H2O 10% (w/v).
- solution of sodium salycilate 0.01M: solution containing 1.60 g/l of sodium salycilate (Na
C7H5O3).
b) Procedure:
immediately after having determined the volatile acidity and the correction for the free and
combined sulphur dioxide, add in the flask 0.5ml of hydrochloric acid, 3ml of solution 0.1M
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of sodium thio-sulphate and 1ml of solution of ammonic ferric sulphate. If salycilic acid is
present a violet colour will appear.
In the flask described above mark the level of the distillate volume. Empty the flask and
wash it. Distill a new sample aliquot of 20ml of wine and collect the distillate in the flask
filling it up to the level mark. Add 0.3ml of hydrochloric acid and 1ml of solution of
ammonic ferric sulphate. The liquid in the flask will turn violet. Pour in a flask ,equal to the
flask with the level mark, some distilled water up to the same distillate level. Add 0.3ml of
hydrochloric acid and 1ml of solution of ammonic ferric sulphate . Add by a burette the
solution of sodium salycilate 0.01M ,until a violet colour is obtained, having the same
intensity of the colour in the flask containing the wine distillate. Being n’’’ the used ml.
subtract 0.1 x n’’’ ml from the volume of n ml of solution of sodium hydroxide 0.1M used
to titrate the distillate acidity during the dosage of the volatile acidity.
References: EEC Reg. n. 266/90 , 17 Sept. 1990, determining the methods to be used for
the analyses in the wine sector.
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Procedure
1) Sample
1-1,5 g of homogeneous sample, weighed with a proximation of 0,1 mg.
It’s suggested to use nitrogen free weighing boats
(Cod. Art. CM0486000, CM0486001). It’s suggested furthermore to introduce the
boat in the test tube immediately after weighing, to avoid the raise of oil by capillarity
along the folded sides of the boat.
The sample containing boat is slipped along the side of the digestion tube, in order to
avoid its dispersion before reaching the bottom.
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Place in position the test tube with digested sample in the unit UDK 139
Set the following analytical parameters:
Factor: 0.00
Addition of reagents:
H2O: 70 ml
H3BO3: :30 ml
NaOH: 50 ml
References: American Society for Testing and Materials. Standard Test Method D
3228-96 Total Nitrogen in Lubricating Oils and Fuel Oils by Modified Kjeldahl
Method.
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Push START to begin NaOH addition and then (after the pause) distillation and
titration.
Distillation time= 4 min
Steam power= 100%
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3) Distillation e titration:
Addition of reagents:
H2O= 50ml.
H3BO3= 30ml (4% p/v)
NaOH= 0ml
The determination of phenols is one of the routine analysis in order to assess the
quality in drinking and ground water and in domestic and industrial wastes.
Procedure
1) Sample:
If the sample to be analyzed contains oxidizing agents (e.g. chlorine), oils and tars or
sulphur compounds, it must be treated at sampling or before distillation according to
the official method prescription.
2) Reagents and equipment:
Phosphoric acid (H3PO4) diluted (1 : 10). 100 ml of phosphoric acid
concentrated (85%, d 1,68) mixed with 900 ml of distilled water.
Copper sulphate (CuSO4 5 H2O) solution 10%. 100 g of salt dissolved in
distilled water for a final volume of 1000 ml.
Distilled water, previously boiled and cooled (Type II)
Aminoantipyrine solution: dissolve 2 g of 4-aminoantipyrine in 100 ml of distilled
water
Potassium ferricyanide solution: dissolve 8 g of K 3Fe(CN)6 in 100 ml of distilled
water
Ammonium chloride solution 2%: dissolve 20 g of NH 4Cl in 1000 ml of distilled
water
Ammonia 25 %
Concentrated phenol solution (1000 mg/l): dissolve 250 mg of phenol in 250 ml
of freshly boiled and cooled distilled water
Diluted phenol solution (10 mg/l): dilute 2.5 ml of the concentrated phenol
solution to 250 ml
Chloroform, analytical grade
3) Sample preparation:
before distillation the water sample is to be acidified to pH 4 by phosphoric acid. Add
1 ml of solution 10% of copper sulphate to 100 ml of sample and introduce in the test
tube.
4) Distillation:
Steam power: 50 %
Position the test tube containing 10 ml of sample into the distillation unit UDK and
start the distillation.
Push START to begin the distillation.
About 200 ml of distillate are collected into a 500 ml volumetric flask.
Blank: 10 ml of distilled water Type II
Dilute the distillation solution to 500 ml using water type II and transfer the solution
into a 1000 ml becker.
Add 25 ml of ammonium chloride solution 2 % by using a pipette and adjust the pH to
10.0 ± 0.2 with some drops of ammonia 25 %.
Transfer the solution into a 500 or 1000 ml separatory funnel and add 3.0 ml of
Aminoantipyrine solution and 3.0 ml of potassium ferricyanide solution. Shake the
separatory funnel and after 5 minutes add 25 ml of chloroform with a pipette.
Shake vigorously for about 2 minutes and let the organic phase settles.
Filter chloroform extract through a filter paper and collect the filtrate in a 100 ml flask.
Transfer the filtrate solution in a 50 mm glass cuvette and read the extinction values
at 460 nm, against distilled water.
Note:
In order to calculate the phenol concentration, create a calibration curve by using
phenols solution diluted in the following range: 0.005-0.100 mg /l phenols.
Dilute different amounts of the phenols diluted solutions to 500 ml using water type II
and proceed the chloroform extraction as indicated above. Record the extinction
value corresponding to the different concentrations.
References:
- APAT CNR IRSA (Water Research Institute), Italy, method n° 5070A1
- EPA method n° 9065
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Procedure
1) Water sample
The sample should be processed as soon as possible after sampling.
If it is to be stored, sodium hydroxide should be added to bring the pH to at least 12,
kept in a completely filled bottle, well closed and maintained at low temperature
(+4°C).
4) Distillation
200 ml of sample are introduced in 1 liter test tube (code A00001083). Add 10 ml of
mercury chloride solution and 5 ml of magnesium chloride solution. 10 ml of
concentrated sulphuric acid are added in the test tube immediately before to start
steam distillation, and test tube with sample is introduced in the unit UDK139.
To avoid damage to the distillator it’s strongly recommended to NOT use the
“removal of distillation residues” function.
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100-120 ml of condensate are collected and the flask content can be adjusted to the
volume with the washings in a volumetric flask 200 ml (the same volume of the
sample). The quantitative determination of the cyanides can be performed by
titrimetry: add 10 drops of Rhodanine indicator into the flask and titrate by silver
nitrate.
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Procedure
1) Reagents:
• sulphuric acid 1 : 1. Dilute 1 volume of concentrated sulphuric acid (H 2SO4) slowly
added to the same volume of water, stirring at intervals.
Do not add water in the acid to avoid dangerous splashings.
• Sodium hydroxide (NaOH), titrated 0,04 N solution.
• Phenolphthalein indicator 0,5 g in 100 ml of distilled water
• Methyl orange indicator solution. 0,05 g in 100 ml of distilled water
• Acetic acid (CH3COOH), 2000 mg/l. Dilute 1,9 ml glacial acetic acid to 1000 ml by
deionized or distilled water. Titrate by sodium hydroxide 0,04 N. 10 ml of the solution
(0,33 meq) require 8,3 ml of sodium hydroxide 0,04 N (phenolphthalein indicator).
2) Sample: 150 : 200 ml of digesting slurry are centrifuged to remove solids and
avoid a possible production of volatile acids by hydrolysis. 5 min at low speed. The
sample is the supernatant liquid.
3) Distillation: 100 ml of sample in a 250 ml test tube are acidified by sulphuric acid
1 : 1, added shaking in 1 ml volumes up to the change of methyl orange indicator
from red to yellow (pH 2,7).
Place the tube with acidified sample in the unit UDK139.
Select the mode “analysis without titration”.
Place in position in the steam distillator UDK139 an Erlenmeyer flask empty; take off
the distillate collecting tube from the condenser and place a new silicone tube,
introduced in the flask.
Set the following parameters:
Reagents addition:
H2O=0.
H3BO3=0.
NaOH=0.
Distillation time = 4 min
steam=100%.
Push START to begin the distillation.
Avoid collection of hydrogen sulphide and carbon dioxide present in the sample
discarding the first 10 ml of condensate. Collect 100 ml of distillate.
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References:
- Lombardo, J.B. (1973). Improved distillation method for volatile acid analysis.
Journal Water Pollution Control Federation. 45:1046-1051.
- Buswell, A.M. (1945). A note on the determination of volatile acids in digester
sludge. Sewage Works Journal. 20: 845-850.
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Procedure
Factor: 0.00
Addition of reagents:
H2O: 50 ml
H3BO3: 30 ml
NaOH: 0 ml.
References:
AOAC, Official Methods of Analysis, method 920.03.
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The controls required by EEC aimed at preventing fish and seafood not suitable for
human consumption from being put on the market, can include some chemical
controls, one of them being the TVBN determination.
The TVBN, expressed as mg/100g of sample, is the content of nitrogen from
ammonia and volatile amines, produced from the proteins during the fish perishing.
The Reg. EEC 2074/2005 fixes the TVBN concentrations for some kinds of fish and
the related analytical methods.
Among the commonly used methods suitable to control the limit value of TVBN, the
EEC Reg. describes also the method from Conway and Byrne (1933).
The fish products (raw material) included in the categories detailed in the above
Reg., are to be considered as “not suitable for human consumption” should there be
any doubt concerning the freshness of the product from the sensorial control, or if the
chemical control indicates that the limit for TVBN (25/30/35 mg/100g depending on
the species of fish) has been exceeded.
The described method is suitable also for meat analysis.
Procedure
2) Distillation: add manually into the test tube 2 g of magnesium oxide (MgO) and 1
antifoam tablet S (code CT0006600).
Place the test tube in the distillator and set the following parameters:
H2O= 50 ml
H3BO3= 30 ml
NaOH= 0 ml
Empy test-tube: NO
Titrant solution: HCl or H2SO4 0,1 N.
Start the distillation and collect 100 ml of distillate in 10 minutes.
If this method is used, select NO as Empy test-tube also during the Wash-down
(chap. 4.3.1).
4) Result:
mg TVBN / 100g = (T-B) x 14.007 x N x 100 / sample weight (g)
5) References:
Pearson D. (1973), Laboratory techniques in food analysis (Conway method).
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21. Declaration of conformity
We the manufacturer VELP SCIENTIFICA s.r.l.
Address Via Stazione, 16
20865 USMATE (MB)
Italy
EN 61010-1/2001
EN 61010-2-010/2003
EN 61010-2-081/2003
EN 61326-1/2006
2006/42/EC
2006/95/EC
2004/108/EC
2011/65/UE (RoHS)
2012/19/UE (RAEE)
plus modifications and that the documents listed in annex I are available at Velp's
offices as foreseen by the machinery directive.
309
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Velp Scientifica – UDK139 Operating Manual
Environment
Thermoreactors ECO series
B.O.D. Determination systems
Refrigerated thermostats
Cooled Incubators
Flocculators
Overhead mixer
Mineralization system for heavy metals trace determination
Turbidimeter
Radiation Detector
Stirring
Heating magnetic stirrers
Vertex digital thermoregulator
Ultraflat magnetic stirrer
Magnetic stirrers
Overhead stirrers
Heating plates
Vortex mixers
Homogenizer
Food&Feed
Digesters DK / DKL series
JP Recirculating Water Pump for fumes aspiration
SMS Scrubber
Distillation Unit UDK series
NDA Dumas unit
Solvent extractors
Raw fiber extractors
Dietary fiber extractors
Laboratory aids
Oxitest Oxidation Test Reactor
Pumps
Recirculating water vacuum pump
Peristaltic pumps
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