CN114487138A - Method for detecting content of alkoxy in sample and application thereof - Google Patents
Method for detecting content of alkoxy in sample and application thereof Download PDFInfo
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- CN114487138A CN114487138A CN202011160395.3A CN202011160395A CN114487138A CN 114487138 A CN114487138 A CN 114487138A CN 202011160395 A CN202011160395 A CN 202011160395A CN 114487138 A CN114487138 A CN 114487138A
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- 238000000034 method Methods 0.000 title claims abstract description 71
- 125000003545 alkoxy group Chemical group 0.000 title claims abstract description 46
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 174
- 238000002290 gas chromatography-mass spectrometry Methods 0.000 claims abstract description 58
- 239000000413 hydrolysate Substances 0.000 claims abstract description 45
- 239000012086 standard solution Substances 0.000 claims abstract description 43
- 238000010438 heat treatment Methods 0.000 claims abstract description 21
- 230000003301 hydrolyzing effect Effects 0.000 claims abstract description 9
- 239000003054 catalyst Substances 0.000 claims description 35
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 33
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 claims description 30
- 239000012452 mother liquor Substances 0.000 claims description 25
- 238000001819 mass spectrum Methods 0.000 claims description 23
- 238000002347 injection Methods 0.000 claims description 20
- 239000007924 injection Substances 0.000 claims description 20
- 238000004949 mass spectrometry Methods 0.000 claims description 20
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 claims description 16
- AMQJEAYHLZJPGS-UHFFFAOYSA-N N-Pentanol Chemical compound CCCCCO AMQJEAYHLZJPGS-UHFFFAOYSA-N 0.000 claims description 16
- 239000012159 carrier gas Substances 0.000 claims description 16
- 230000007062 hydrolysis Effects 0.000 claims description 16
- 238000006460 hydrolysis reaction Methods 0.000 claims description 16
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 16
- 238000007865 diluting Methods 0.000 claims description 14
- ZSIAUFGUXNUGDI-UHFFFAOYSA-N hexan-1-ol Chemical compound CCCCCCO ZSIAUFGUXNUGDI-UHFFFAOYSA-N 0.000 claims description 14
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 claims description 14
- 238000004817 gas chromatography Methods 0.000 claims description 13
- 239000007789 gas Substances 0.000 claims description 11
- 150000001298 alcohols Chemical class 0.000 claims description 9
- -1 methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, n-pentoxy, isopentoxy, n-hexoxy, isohexoxy, n-heptoxy, isoheptoxy, n-octoxy, isooctoxy, n-nonoxy, isononyloxy, n-pentoxy Chemical group 0.000 claims description 8
- 239000002904 solvent Substances 0.000 claims description 8
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 6
- WEVYAHXRMPXWCK-UHFFFAOYSA-N Acetonitrile Chemical compound CC#N WEVYAHXRMPXWCK-UHFFFAOYSA-N 0.000 claims description 6
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 claims description 6
- 230000005540 biological transmission Effects 0.000 claims description 6
- 125000004432 carbon atom Chemical group C* 0.000 claims description 6
- 239000010413 mother solution Substances 0.000 claims description 6
- 238000005070 sampling Methods 0.000 claims description 5
- BBMCTIGTTCKYKF-UHFFFAOYSA-N 1-heptanol Chemical compound CCCCCCCO BBMCTIGTTCKYKF-UHFFFAOYSA-N 0.000 claims description 4
- OFBQJSOFQDEBGM-UHFFFAOYSA-N Pentane Chemical compound CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 claims description 4
- 239000011954 Ziegler–Natta catalyst Substances 0.000 claims description 4
- KBPLFHHGFOOTCA-UHFFFAOYSA-N caprylic alcohol Natural products CCCCCCCCO KBPLFHHGFOOTCA-UHFFFAOYSA-N 0.000 claims description 4
- MWKFXSUHUHTGQN-UHFFFAOYSA-N decan-1-ol Chemical compound CCCCCCCCCCO MWKFXSUHUHTGQN-UHFFFAOYSA-N 0.000 claims description 4
- ZXEKIIBDNHEJCQ-UHFFFAOYSA-N isobutanol Chemical compound CC(C)CO ZXEKIIBDNHEJCQ-UHFFFAOYSA-N 0.000 claims description 4
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 claims description 4
- ZWRUINPWMLAQRD-UHFFFAOYSA-N nonan-1-ol Chemical compound CCCCCCCCCO ZWRUINPWMLAQRD-UHFFFAOYSA-N 0.000 claims description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 3
- 229910052799 carbon Inorganic materials 0.000 claims description 3
- 238000006243 chemical reaction Methods 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 3
- 238000002604 ultrasonography Methods 0.000 claims description 3
- PCWGTDULNUVNBN-UHFFFAOYSA-N 4-methylpentan-1-ol Chemical compound CC(C)CCCO PCWGTDULNUVNBN-UHFFFAOYSA-N 0.000 claims description 2
- ZVHAANQOQZVVFD-UHFFFAOYSA-N 5-methylhexan-1-ol Chemical compound CC(C)CCCCO ZVHAANQOQZVVFD-UHFFFAOYSA-N 0.000 claims description 2
- BWDBEAQIHAEVLV-UHFFFAOYSA-N 6-methylheptan-1-ol Chemical compound CC(C)CCCCCO BWDBEAQIHAEVLV-UHFFFAOYSA-N 0.000 claims description 2
- QDTDKYHPHANITQ-UHFFFAOYSA-N 7-methyloctan-1-ol Chemical compound CC(C)CCCCCCO QDTDKYHPHANITQ-UHFFFAOYSA-N 0.000 claims description 2
- PLLBRTOLHQQAQQ-UHFFFAOYSA-N 8-methylnonan-1-ol Chemical compound CC(C)CCCCCCCO PLLBRTOLHQQAQQ-UHFFFAOYSA-N 0.000 claims description 2
- PHTQWCKDNZKARW-UHFFFAOYSA-N isoamylol Chemical compound CC(C)CCO PHTQWCKDNZKARW-UHFFFAOYSA-N 0.000 claims description 2
- 125000005921 isopentoxy group Chemical group 0.000 claims description 2
- TVMXDCGIABBOFY-UHFFFAOYSA-N n-Octanol Natural products CCCCCCCC TVMXDCGIABBOFY-UHFFFAOYSA-N 0.000 claims description 2
- 125000004430 oxygen atom Chemical group O* 0.000 claims description 2
- 238000003908 quality control method Methods 0.000 claims description 2
- 238000012544 monitoring process Methods 0.000 claims 1
- 238000001514 detection method Methods 0.000 abstract description 47
- 239000000126 substance Substances 0.000 abstract description 13
- 230000035945 sensitivity Effects 0.000 abstract description 7
- 150000002500 ions Chemical class 0.000 description 44
- 239000000243 solution Substances 0.000 description 24
- NMRPBPVERJPACX-UHFFFAOYSA-N (3S)-octan-3-ol Natural products CCCCCC(O)CC NMRPBPVERJPACX-UHFFFAOYSA-N 0.000 description 11
- WOFPPJOZXUTRAU-UHFFFAOYSA-N 2-Ethyl-1-hexanol Natural products CCCCC(O)CCC WOFPPJOZXUTRAU-UHFFFAOYSA-N 0.000 description 11
- YIWUKEYIRIRTPP-UHFFFAOYSA-N 2-ethylhexan-1-ol Chemical compound CCCCC(CC)CO YIWUKEYIRIRTPP-UHFFFAOYSA-N 0.000 description 11
- 230000000052 comparative effect Effects 0.000 description 10
- 108010009736 Protein Hydrolysates Proteins 0.000 description 7
- 238000011084 recovery Methods 0.000 description 7
- 125000001301 ethoxy group Chemical group [H]C([H])([H])C([H])([H])O* 0.000 description 6
- 239000001307 helium Substances 0.000 description 6
- 229910052734 helium Inorganic materials 0.000 description 6
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 6
- 229910052751 metal Inorganic materials 0.000 description 6
- 239000002184 metal Substances 0.000 description 6
- 238000002360 preparation method Methods 0.000 description 6
- 238000005303 weighing Methods 0.000 description 6
- 239000008367 deionised water Substances 0.000 description 5
- 229910021641 deionized water Inorganic materials 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 229910052749 magnesium Inorganic materials 0.000 description 3
- 239000011777 magnesium Substances 0.000 description 3
- 230000014759 maintenance of location Effects 0.000 description 3
- 238000007789 sealing Methods 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 2
- TWRXJAOTZQYOKJ-UHFFFAOYSA-L Magnesium chloride Chemical compound [Mg+2].[Cl-].[Cl-] TWRXJAOTZQYOKJ-UHFFFAOYSA-L 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- SXSVTGQIXJXKJR-UHFFFAOYSA-N [Mg].[Ti] Chemical compound [Mg].[Ti] SXSVTGQIXJXKJR-UHFFFAOYSA-N 0.000 description 2
- 150000004703 alkoxides Chemical class 0.000 description 2
- 239000000969 carrier Substances 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 238000000605 extraction Methods 0.000 description 2
- 238000000622 liquid--liquid extraction Methods 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000002552 multiple reaction monitoring Methods 0.000 description 2
- 238000000638 solvent extraction Methods 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- RVDLHGSZWAELAU-UHFFFAOYSA-N 5-tert-butylthiophene-2-carbonyl chloride Chemical compound CC(C)(C)C1=CC=C(C(Cl)=O)S1 RVDLHGSZWAELAU-UHFFFAOYSA-N 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 1
- 150000001336 alkenes Chemical class 0.000 description 1
- 125000000217 alkyl group Chemical group 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 239000003125 aqueous solvent Substances 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000002546 full scan Methods 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 150000002431 hydrogen Chemical group 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910001629 magnesium chloride Inorganic materials 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 125000000956 methoxy group Chemical group [H]C([H])([H])O* 0.000 description 1
- GRVDJDISBSALJP-UHFFFAOYSA-N methyloxidanyl Chemical group [O]C GRVDJDISBSALJP-UHFFFAOYSA-N 0.000 description 1
- 125000006606 n-butoxy group Chemical group 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 description 1
- 238000006362 organocatalysis Methods 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000009210 therapy by ultrasound Methods 0.000 description 1
- 238000002411 thermogravimetry Methods 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
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- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
Abstract
The invention relates to a chemical substance detection technology, and discloses a method for detecting the content of alkoxy in a sample and application thereof, wherein the method comprises the following steps: detecting the standard solution containing alcohol by a headspace-gas chromatography-mass spectrometry combined method to obtain a chromatogram of the standard solution; taking the alcohol content in the standard solution as an X axis, and taking the peak area of the alcohol in the chromatogram of the standard solution as a Y axis to draw a standard curve; hydrolyzing the sample to obtain a hydrolysate containing alcohol, and detecting the hydrolysate by a headspace-gas chromatography-mass spectrometry combined method under the same condition as the step (1) to obtain a chromatogram of the hydrolysate; quantifying the content of the alkoxy in the sample according to the peak area of the alcohol and a standard curve in the chromatogram of the hydrolysate; the headspace conditions in the combined headspace-gas chromatography-mass spectrometry include: the heating temperature of the headspace is 60-95 ℃, and the heating time of the headspace is 1-60 min. The method has the advantages of high sensitivity and high accuracy of detection results, and is convenient to operate.
Description
Technical Field
The invention relates to the field of chemical substance detection, in particular to a method for detecting alkoxy content in a sample and application thereof.
Background
Metal alkoxides which are used in many organocatalytic reactions, the metal alkoxide M (OR) x, which consists of a metal M with a valence x, an alkyl R, is a metal-oxygen-carbon bond system. For example, magnesium alkoxides are important carriers for Ziegler-Natta (Ziegler-Natta) catalysts of the titanium-magnesium system, and can be obtained by reacting magnesium with an alcohol or an alcoholate of magnesium chloride with an alcohol. The content of alkoxy groups during the olefin polymerization has a significant influence on the catalyst performance.
For common titanium-magnesium system carriers, such as magnesium ethoxide, ethoxy is converted into ethanol after decomposition, and the ethoxy content can be obtained by measuring the ethanol content, the test methods reported in the literature include gas chromatography, thermogravimetry and the like, the ethoxy is required to be converted into ethanol before the test, a liquid-liquid extraction method is usually adopted for separation, the operation is complex, for volatile small molecular organic matters such as ethanol, the loss of the volatile small molecular organic matters such as ethanol is easily caused by adopting the liquid-liquid extraction method, the error of the detection result is large, the sensitivity of the detection method is poor due to the interference of a co-extracted substance, and meanwhile, the pollution is caused to parts such as a sample injection instrument port and the environment.
Disclosure of Invention
The invention aims to solve the problems of poor sensitivity, large error, complex operation and easy pollution to an instrument sample inlet and environment of a detection method in the prior art, and provides a method for detecting the content of alkoxy in a sample and application thereof.
In the present invention, the sensitivity refers to the detection limit of the detection method, i.e., the lowest content of alkoxy groups that can be detected by the method of the present invention; the accuracy of the method is characterized by the actual recovery rate, wherein the actual recovery rate is the content of the alcohol obtained by detecting the standard solution divided by the actual content of the alcohol in the standard solution, and the higher the actual recovery rate is, the higher the accuracy is, otherwise, the lower the accuracy is.
In order to achieve the above object, one aspect of the present invention provides a method for detecting the content of alkoxy groups in a sample, the method comprising the steps of:
(1) respectively detecting standard solutions with different alcohol contents by a headspace-gas chromatography-mass spectrometry combined method to obtain chromatograms of the standard solutions;
(2) taking the content of alcohol in the standard solution as an X axis, and taking the peak area of the alcohol in the chromatogram of the standard solution as a Y axis to draw a standard curve;
(3) hydrolyzing the sample to obtain a hydrolysate containing alcohol, and detecting the hydrolysate containing alcohol by using a headspace-gas chromatography-mass spectrometry combined method under the same condition as the step (1) to obtain a chromatogram of the hydrolysate;
(4) quantifying the content of the alkoxy in the sample according to the peak area of alcohol in the chromatogram of the hydrolysate obtained in the step (3) and the standard curve in the step (2);
wherein the headspace-gas chromatography-mass spectrometry combined method comprises the following conditions: the heating temperature of the headspace is 60-95 ℃, and the heating time of the headspace is 1-60 min.
The second aspect of the present invention provides the use of the method of the first aspect for detecting the content of alkoxy groups in a sample or for controlling the quality of catalyst production.
The method for detecting the content of the alkoxy in the sample has the advantages of high sensitivity and high accuracy of the detection result, is convenient to operate, and does not need to carry out complicated extraction steps. Particularly, the preferable embodiment of the invention can obtain better technical effect, the actual recovery rate can reach more than 95 percent, the detection limit of the standard solution can reach 0.001mg/mL, and the detection limit of the alkoxy content can reach 1 mu g/g in terms of alkoxy content.
Drawings
FIG. 1 is a selected ion scan chromatogram of a working curve standard point solution of example 1 with each alcohol content of 1 mg/mL;
FIG. 2 is a selected ion scan chromatogram of a working curve standard point solution of example 1 with each alcohol content of 2 mg/mL;
FIG. 3 is a selected ion scan chromatogram of a working curve standard point solution of example 1 with 5mg/mL of each alcohol content;
FIG. 4 is a selected ion scan chromatogram of a standard point solution of a working curve of example 1 having an alcohol content of 10 mg/mL;
FIG. 5 is a selected ion scan chromatogram of a working curve standard point solution of example 1 with each alcohol content of 20 mg/mL;
FIG. 6 is a selective ion scanning chromatogram obtained by detecting the hydrolysate of the catalyst 1 in example 1;
FIG. 7 is a total ion chromatogram of a full scan obtained by detecting hydrolysate of catalyst 2 in example 2;
FIG. 8 is a mass spectrum of catalyst 2 hydrolysate in example 2;
FIG. 9 is a total ion flow chromatogram for a full scan of catalyst 3 hydrolysate in example 3;
FIG. 10 is a total ion flow chromatogram for a full scan of catalyst 3 hydrolysate in comparative example 1;
fig. 11 is a full scan total ion current chromatogram of catalyst 3 hydrolysate in comparative example 2.
Detailed Description
The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.
In a first aspect, the present invention provides a method for detecting the content of alkoxy groups in a sample, the method comprising the steps of:
(1) respectively detecting standard solutions with different alcohol contents by a headspace-gas chromatography-mass spectrometry combined method to obtain chromatograms of the standard solutions;
(2) taking the content of alcohol in the standard solution as an X axis, and taking the peak area of the alcohol in the chromatogram of the standard solution as a Y axis to draw a standard curve;
(3) hydrolyzing the sample to obtain a hydrolysate containing alcohol, and detecting the hydrolysate containing alcohol by using a headspace-gas chromatography-mass spectrometry combined method under the same condition as the step (1) to obtain a chromatogram of the hydrolysate;
(4) quantifying the content of the alkoxy in the sample according to the peak area of alcohol in the chromatogram of the hydrolysate obtained in the step (3) and the standard curve in the step (2);
wherein the headspace-gas chromatography-mass spectrometry combined method comprises the following conditions: the heating temperature of the headspace is 60-95 ℃, and the heating time of the headspace is 1-60 min.
In the present invention, the headspace in the combined headspace-gas chromatography-mass spectrometry refers to a method of directly introducing a volatile component in a liquid or solid sample into a gas chromatograph by using a headspace injector, wherein the headspace injector can be connected to the gas chromatograph.
In the present invention, it is understood that in step (3), the sample is hydrolyzed, and the hydrolyzed alkoxy group forms an alcohol having the same carbon chain structure and carbon number as the hydrolyzed alkoxy group, for example, the hydrolyzed methoxy group forms methanol, the hydrolyzed ethoxy group forms ethanol, and the hydrolyzed n-butoxy group forms n-butanol.
In the present invention, preferably, the alkoxy group in the sample is combined with the metal element in a form forming a metal-oxygen bond; more preferably, the metal element is selected from alkaline earth metal elements and/or transition metal elements, and more preferably, the metal element is selected from at least one of magnesium element, zinc element, lead element, nickel element, tin element, aluminum element and titanium element.
In the present invention, the kind of the sample is not particularly limited as long as the contained alkoxy group is capable of forming the corresponding alcohol under the hydrolysis condition and the remaining components produced after the hydrolysis of the sample do not affect the detection sensitivity and the accuracy of the detection result, and preferably, the sample is a catalyst containing an alkoxy group and/or a catalyst support containing an alkoxy group, more preferably a ziegler natta catalyst containing an alkoxy group and/or a ziegler natta catalyst support containing an alkoxy group.
In the present invention, in order to further improve the accuracy of the detection result, the headspace heating temperature in the combined headspace-gas chromatography-mass spectrometry is preferably 80 to 95 ℃ (for example, 80 ℃, 83 ℃, 85 ℃, 87 ℃, 89 ℃, 91 ℃, 93 ℃, 95 ℃, or any value between any two values), and preferably 90 to 95 ℃.
In the present invention, in order to further improve the accuracy of the detection result, preferably, the headspace heating time for performing headspace in the headspace-gas chromatography-mass spectrometry combined method is 3 to 15min (for example, may be 3min, 4min, 5min, 6min, 7min, 8min, 9min, 10min, 11min, 12min, 13min, 14min, 15min, or any value between any two values), and preferably 5 to 10 min.
In the present invention, in order to further improve the accuracy of the detection result, the temperature of the transmission line for conducting the headspace in the combined headspace-gas chromatography-mass spectrometry is preferably 70 to 150 ℃ (for example, may be 70 ℃, 80 ℃, 90 ℃, 100 ℃, 110 ℃, 120 ℃, 130 ℃, 140 ℃, 150 ℃, or any value between any two values), and is preferably 90 to 110 ℃.
In the present invention, in order to further improve the accuracy of the detection result, the temperature of the headspace sampling needle for performing the headspace in the headspace-gas chromatography-mass spectrometry combined method is preferably 80 to 150 ℃ (for example, may be 80 ℃, 90 ℃, 100 ℃, 110 ℃, 120 ℃, 130 ℃, 140 ℃, 150 ℃, or any value between any two values), and is preferably 100 ℃ to 120 ℃.
In the present invention, the kind of the alkoxy group is not particularly limited, and preferably, the alkoxy group is selected from one or more of alkoxy groups having 1 to 20 carbon atoms, more preferably, from one or more of alkoxy groups having 1 to 10 carbon atoms; more preferably, the alkoxy group contains one oxygen atom; further preferably, the alkoxy group is selected from one or more of methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, n-pentoxy, isopentoxy, n-hexoxy, isohexoxy, n-heptoxy, isoheptoxy, n-octoxy, isooctoxy (e.g., 2-ethyl-1-hexoxy), n-nonoxy, isononyloxy, n-pentoxy, and isopentoxy.
In the present invention, there is no particular requirement for preparing the alcohol-containing standard solution, and the preparation may be performed according to a conventional method, and in order to further improve the accuracy of the detection result, it is preferable that the preparation method of the standard solution with different alcohol contents includes: a) preparing a standard mother solution with the alcohol content of 1-100mg/mL, preferably 1-25 mg/mL; b) and diluting the standard mother liquor step by step into standard solutions with different alcohol contents. It is understood that, when 1 alcohol is used, the alcohol content in the standard mother liquor is 1-100mg/mL, preferably 1-25 mg/mL; when the number of the alcohols is at least 2, the content of each alcohol in the standard mother liquor is 1-100mg/mL, preferably 1-25 mg/mL.
In the present invention, the kind of the alcohol is not particularly limited, and preferably, the alcohol is one or more selected from alcohols having 1 to 20 carbon atoms, and more preferably, one or more selected from alcohols having 1 to 10 carbon atoms. More preferably, the alcohol is a monohydric alcohol having 1 to 10 carbon atoms, and still more preferably a saturated monohydric alcohol. Further preferably, the alcohol is selected from one or more of methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, n-pentanol, isopentanol, n-hexanol, isohexanol, n-heptanol, isoheptanol, n-octanol, isooctanol (e.g., 2-ethyl-1-hexanol), n-nonanol, isononanol, n-decanol, and isodecanol.
It is understood that the mother liquor generally has a certain shelf life, and needs to be re-prepared after expiration, and the shelf life of the standard mother liquor prepared in the invention is 0.5-1 month.
In the present invention, the alcohol standard used to prepare the standard solution is preferably > 95% pure, more preferably > 99% pure.
In the present invention, there is no particular limitation on the kind of solvent used for preparing and diluting the mother liquor, and preferably, the solvents used for preparing and diluting the mother liquor are each independently selected from the group consisting of solvents miscible with the alcohol; more preferably, the solvent is selected from at least one of ethyl acetate, water, n-pentane, n-hexane, acetonitrile and acetone; further preferably, the solvent is ethyl acetate and/or water.
In the present invention, the number of the standard solutions with different alcohol contents diluted in step b) is not particularly limited, and may be the number conventionally used in the art, such as at least 5 standard solutions with different alcohol contents.
In the present invention, the linear range of the standard curve is not particularly limited, and in order to further improve the accuracy of the detection result, the linear range of the standard curve is preferably 0.001 to 100mg/mL, and preferably 0.01 to 25 mg/mL; the linear correlation coefficient is greater than 0.99.
In the present invention, in order to further improve the accuracy of the detection result, it is preferable that when the standard solution contains at least 2 kinds of alcohols, the standard curve of each alcohol is drawn by using the content of each alcohol in the standard solution as an X-axis and the peak area of each corresponding alcohol in the total ion chromatogram of the standard solution as a Y-axis.
In the present invention, in order to further enhance the effect of hydrolysis, it is preferable that the hydrolysis is performed under conditions including: the hydrolysis temperature is 0-50 ℃, preferably 15-30 ℃; the hydrolysis time is 5-30min, preferably 5-10 min.
In the present invention, in order to further enhance the effect of hydrolysis, preferably, the hydrolysis is performed under the condition of ultrasound with a power of 40 to 300W, more preferably 50 to 100W.
In the present invention, in order to further enhance the effect of hydrolysis, the amount of water used for hydrolysis is preferably 1 to 1000mL, more preferably 10 to 100mL, per 1g of sample. It should be noted that the hydrolysate obtained by hydrolyzing the sample is still suitable for the standard curve obtained by preparing and diluting the mother solution with a non-aqueous solvent, and the detection result has high accuracy.
In the present invention, the amount of the sample detected by the headspace-gas chromatography-mass spectrometry combined method is not particularly limited, and in order to further improve the accuracy of the detection result, the amount of the sample in the headspace-gas chromatography-mass spectrometry combined method is preferably 2 to 1000. mu.L, and preferably 10 to 100. mu.L (for example, 10. mu.L, 15. mu.L, 20. mu.L, 30. mu.L, 40. mu.L, 50. mu.L, 60. mu.L, 70. mu.L, 80. mu.L, 90. mu.L, 100. mu.L, or any value therebetween).
In the present invention, preferably, the conditions for performing gas chromatography in the combined headspace-gas chromatography-mass spectrometry are as follows: the temperature of the sample inlet is 180-280 ℃, the type of the sample inlet is a split/non-split sample inlet, the split ratio of the sample inlet is 5-100:1, the flow rate of the carrier gas is 0.5-1.5mL/min, the column temperature is kept for 0-5min at 35-50 ℃, the temperature is programmed to 200-280 ℃, the temperature is kept for 0-15min, the temperature programming speed is 2-50 ℃/min, and the temperature of the chromatographic mass spectrometry connecting rod is 180-280 ℃. The accuracy of the detection results can be further improved by using the preferred gas chromatography conditions. The split ratio refers to the ratio of the amount of gas carried out of the off-gas line to the amount of gas carried into the chromatogram to split the total sample feed.
In the invention, in order to further improve the accuracy of the detection result, preferably, the injection port temperature of the gas chromatography in the headspace-gas chromatography-mass spectrometry is 180-280 ℃, and more preferably 200-250 ℃.
In the invention, in order to further improve the accuracy of the detection result, preferably, the type of the sample inlet of the gas chromatograph in the headspace-gas chromatograph-mass spectrometer is a split/non-split sample inlet, and the split ratio of the sample inlet is 5-100:1, and more preferably 30-50: 1.
In the present invention, in order to further improve the accuracy of the detection result, it is preferable that the flow rate of the carrier gas for gas chromatography in the headspace-gas chromatography-mass spectrometry is 0.5 to 1.5mL/min, more preferably 0.8 to 1.2 mL/min.
In the present invention, there is no particular limitation on the type of the carrier gas for gas chromatography in the combined headspace-gas chromatography-mass spectrometry, and preferably, the carrier gas for gas chromatography in the combined headspace-gas chromatography-mass spectrometry is selected from hydrogen, nitrogen, helium or argon.
In the invention, in order to further improve the accuracy of the detection result, preferably, the column temperature of the gas chromatography is kept for 0-5min at 35-50 ℃, the temperature is programmed to 200-280 ℃, and the column temperature is kept for 0-15 min; more preferably, the temperature is maintained at 35-40 ℃ for 1-3min, and the temperature is programmed to 240-260 ℃ for 0.3-10 min.
Further preferably, the temperature programming rate is 2-50 ℃/min, more preferably 5-25 ℃/min.
In the invention, in order to further improve the accuracy of the detection result, the temperature of the chromatographic mass spectrum connecting rod in the headspace-gas chromatography-mass spectrum combined method is preferably 180-280 ℃, and more preferably 200-260 ℃.
In the present invention, preferably, the conditions for performing mass spectrometry in the headspace-gas chromatography-mass spectrometry combined method are as follows: the mass spectrum ion source is an electron bombardment ionization source, the electron energy is 50-80eV, the temperature of the mass spectrum ion source is 200-280 ℃, and the mass spectrum collection type is full scanning and/or selective ion scanning; alternatively, the mass spectrometry acquisition type is a full scan and/or a multiple reaction monitoring scan. The accuracy of the detection result can be further improved by adopting the optimal geological spectrum condition.
In the present invention, in order to further improve the accuracy of the detection result, preferably, the mass spectrometry ion source is an electron bombardment ionization source.
More preferably, the electron energy of the electron bombardment ionization source is 50-80 eV.
In the invention, in order to further improve the accuracy of the detection result, the mass spectrometry ion source temperature is preferably 200-.
In the present invention, in order to further improve the accuracy of the detection result, preferably, the mass spectrum acquisition type is a full scan and/or a selective ion scan.
In the present invention, in order to further improve the accuracy of the detection result, preferably, the mass spectrometry acquisition type is a full scan and/or a multiple reaction monitoring scan.
More preferably, the mass spectrometry acquisition types are full scan and selective ion scan; alternatively, the type of mass spectrometry acquisition is a selective ion scan.
According to a particularly preferred embodiment of the invention, the method comprises the following steps:
(a) weighing at least one alcohol, respectively weighing 0.8-1.2g of each alcohol, mixing, and adding ethyl acetate to prepare standard mother liquor with the content of each alcohol being 80-100 mg/mL;
diluting the standard mother liquor by ethyl acetate step by step into working curve standard point solutions with the alcohol contents of 1-1.5mg/mL, 1.8-2.2mg/mL, 4.5-5.5mg/mL, 9.5-10.5mg/mL and 19.5-20.5mg/mL, placing 18-22 mu L of the 5 working curve standard point solutions into respective headspace bottles, and detecting by respectively adopting a headspace-gas chromatography-mass spectrometry combined method to respectively obtain chromatograms of the working curve standard point solutions;
(b) respectively taking the content of each alcohol in the standard solution as an X axis and respectively taking the peak area of each corresponding alcohol in the chromatogram as a Y axis to draw a standard curve of each alcohol;
(c) the amount of water used for hydrolysis was 10 to 100mL relative to 1g of the sample, and a hydrolysate containing alcohol was obtained. Detecting the hydrolysate containing the alcohol by using a headspace-gas chromatography-mass spectrometry combination method under the same conditions as the step (a) to obtain a chromatogram map of the hydrolysate;
(d) quantifying the content of alkoxy groups in the sample according to the peak area of alcohol in the chromatogram of the hydrolysate obtained in step (c) and the standard curve of step (b);
wherein, the headspace condition in the combined headspace-gas chromatography-mass spectrometry comprises the following steps: the heating temperature of the headspace is 85-95 ℃, the heating time of the headspace is 4-6min, the temperature of the transmission line is 95-105 ℃, and the temperature of the headspace sampling needle is 105-.
The conditions of gas chromatography in the headspace-gas chromatography-mass spectrometry combined method comprise: the temperature of the sample inlet is 240-260 ℃, the type of the sample inlet is a split/non-split sample inlet, the split ratio of the sample inlet is 48-52:1, the carrier gas is high-purity helium, the flow rate of the carrier gas is 0.8-1.2mL/min, the temperature of the chromatographic column is kept for 2-3min at 35-38 ℃, the temperature is programmed to 240-260 ℃, the temperature is kept for 0.4-0.6min, the temperature rise speed is 22-25 ℃/min, and the temperature of the chromatographic mass spectrum connecting rod is 245-255 ℃;
the mass spectrum conditions in the headspace-gas chromatography-mass spectrometry combined method comprise: electron bombardment ionization source (EI source), wherein the temperature of the electron energy is 65-75eV, and the temperature of the mass spectrum ion source is 225-235 ℃; the mass spectrometry acquisition type is selected ion Scanning (SIM).
In a second aspect, the present invention provides the use of a method according to the first aspect for detecting the level of alkoxy groups in a sample or for quality control of catalyst production.
The present invention will be described in detail below by way of examples. In the following examples of the present invention,
detecting the content of alcohol obtained by adding the standard solution and/or the actual content of the alcohol in the standard solution;
the headspace sampler is an Agilent G1888A headspace sampler;
the gas chromatography-mass spectrometer is an Agilent 7890A-5975C gas chromatography-mass spectrometer;
the chromatographic column is as follows: HP-5MS column (30 m.times.0.25 mm.times.0.25 μm);
the methanol, the ethanol, the n-propanol, the isopropanol, the n-butanol, the n-pentanol, the n-hexanol and the 2-ethyl-1-hexanol are all analytically pure, and the content is more than or equal to 99.5 weight percent.
Example 1
(1) Preparation of a standard curve: respectively weighing 1.0g of methanol, ethanol, n-propanol, n-butanol, n-pentanol and n-hexanol, placing the weighed materials in a 10mL volumetric flask, adding ethyl acetate to a constant volume to scale marks, and preparing standard mother liquor with the content of each alcohol of the methanol, the ethanol, the n-propanol, the n-butanol, the n-pentanol and the n-hexanol being 100 mg/mL;
diluting the standard mother liquor by ethyl acetate step by step into working curve standard point solutions with the alcohol contents of 1mg/mL, 2mg/mL, 5mg/mL, 10mg/mL and 20mg/mL, taking 20 mu L of the 5 working curve standard point solutions, placing the 5 working curve standard point solutions into respective 20mL headspace bottles, respectively detecting by adopting a headspace-gas chromatography-mass spectrometry combination method, and respectively obtaining selective ion scanning chromatograms (shown in figures 1-5) of the working curve standard point solutions, wherein the retention time of each alcohol is shown in Table 1;
(2) respectively taking the content of each alcohol in the standard solution as an X axis and the peak area of each corresponding alcohol in the selective ion scanning chromatogram as a Y axis, drawing a standard curve (the linear range is shown in table 1) of each alcohol, and respectively fitting to obtain a regression equation (shown in table 1) of each alcohol;
(3) putting 0.1g of catalyst 1 into a 10mL volumetric flask, adding water to a constant volume, and hydrolyzing for 10min at 20 ℃ under the ultrasonic condition to obtain hydrolysate containing methanol and ethanol, wherein the ultrasonic power is 100W. Adding 20 mu L of hydrolysate into a 20mL headspace bottle, sealing, and detecting by headspace-gas chromatography-mass spectrometry to obtain a selective ion scanning chromatogram of the hydrolysate of the catalyst 1 (see figure 6);
(4) respectively substituting the peak area of methanol and the peak area of ethanol in the selective ion scanning chromatogram of the catalyst 1 hydrolysate into respective regression equations, calculating to obtain the content of methanol and the content of ethanol in the hydrolysate, and then calculating to obtain the content of methoxyl and the content of ethoxyl in the catalyst 1, wherein the calculation results are shown in Table 1;
(5) mixing methanol, ethanol, n-propanol, n-butanol, n-pentanol and n-hexanol in equal amount, and then fixing the volume by using deionized water to obtain a solution with the alcohol content of 7.5mg/mL as a standard solution; and (3) putting the prepared 7.5mg/mL solution into three 20mL headspace bottles, wherein the amount of the sample filled in each headspace bottle is 20 mu L, performing ultrasonic treatment for 10min, respectively detecting by adopting a headspace-gas chromatography-mass spectrometry combination method to respectively obtain the peak areas of 6 alcohols of 3 samples, substituting the peak areas into respective corresponding regression equations, and calculating to obtain the recovery rate of the 6 alcohols in the standard solution, wherein the recovery rate of the 6 alcohols is more than 95%.
(6) Gradually diluting the 100mg/mL standard mother liquor in the step (1) to 0.1mg/mL, 0.05mg/mL and 0.001mg/mL, and taking the peak area signal-to-noise ratio of each substance as a detection limit, wherein the result shows that the peak area signal-to-noise ratio of each substance is more than 3 when the standard mother liquor is diluted to 0.001mg/mL, namely the detection limit is at least 0.001 mg/mL.
Wherein:
the conditions for headspace in the combined headspace-gas chromatography-mass spectrometry include: the headspace heating temperature is 90 ℃, the headspace heating time is 5min, the transmission line temperature is 100 ℃, and the headspace sampling needle temperature is 110 ℃.
The conditions of gas chromatography in the headspace-gas chromatography-mass spectrometry combined method comprise: the injection port temperature is 250 ℃, the injection port type is a split/non-split injection port, the split ratio of the injection port is 50:1, the carrier gas is high-purity helium, the carrier gas flow rate is 1.0mL/min, the column temperature of the chromatographic column is kept for 2.5min at 35 ℃, the temperature is programmed to 250 ℃, kept for 0.5min, the temperature rise speed is 25 ℃/min, and the temperature of the chromatographic mass spectrum connecting rod is 250 ℃;
the mass spectrum conditions in the headspace-gas chromatography-mass spectrometry combined method comprise: electron bombardment ionization source (EI source), electron energy is 70eV, and the temperature of mass spectrum ion source is 230 ℃; the mass spectrometry acquisition type is selected ion Scanning (SIM). The SIM characteristic ions of all the substances are respectively as follows: methanol m/z 31, ethanol m/z 45, n-propanol m/z 31, n-butanol m/z 31, 42, n-pentanol m/z 31, 56, n-hexanol m/z 31, 56.
Example 2
(1) Preparation of a standard curve: weighing 1.0g of 2-ethyl-1-hexanol, placing the weighed 2-ethyl-1-hexanol in a 10mL volumetric flask, adding ethyl acetate to a constant volume to a scale mark, and preparing a standard mother solution with the content of the 2-ethyl-1-hexanol of 100 mg/mL;
gradually diluting the standard mother liquor into working curve standard point solutions with the contents of 2-ethyl-1-hexanol being 1mg/mL, 2mg/mL, 5mg/mL, 10mg/mL and 20mg/mL respectively by using ethyl acetate, taking 20 mu L of the 5 working curve standard point solutions, placing the solutions into respective 20mL headspace bottles, and respectively detecting by adopting a headspace-gas chromatography-mass spectrometry combination method to obtain a selective ion scanning chromatogram of the working curve standard point solution, wherein the retention time of the 2-ethyl-1-hexanol is shown in Table 1;
(2) taking the content of pentanol in the standard solution as an X axis, taking the peak area of 2-ethyl-1-hexanol in the selected ion scanning chromatogram as a Y axis, drawing a standard curve (the linear range is shown in table 1), and fitting to obtain a regression equation (shown in table 1);
(3) putting 1.0g of catalyst 2 into a 10mL volumetric flask, adding water to a constant volume, and hydrolyzing for 10min at 25 ℃ under the ultrasonic condition to obtain hydrolysate containing 2-ethyl-1-hexanol, wherein the ultrasonic power is 100W. Adding 20 μ L of hydrolysate into 20mL headspace bottle, sealing, and detecting by headspace-gas chromatography-mass spectrometry to obtain total ion current chromatogram (shown in figure 7) of catalyst 2 hydrolysate, wherein the mass chromatogram is shown in figure 8;
(4) respectively substituting the peak area of the 2-ethyl-1-hexanol in the selective ion scanning chromatogram of the catalyst 2 hydrolysate into a regression equation to obtain the content of the 2-ethyl-1-hexanol in the hydrolysate, and then calculating to obtain the content of the 2-ethyl-1-hexyloxy in the catalyst 2, wherein the calculation result is shown in table 1.
(5) Gradually diluting the 100mg/mL standard mother liquor in the step (1) to 0.1mg/mL, 0.05mg/mL and 0.001mg/mL, and taking the peak area signal-to-noise ratio of each substance as a detection limit, wherein the result shows that the peak area signal-to-noise ratio of each substance is more than 3 when the standard mother liquor is diluted to 0.001mg/mL, namely the detection limit is at least 0.001 mg/mL.
Wherein:
the conditions for headspace in the combined headspace-gas chromatography-mass spectrometry include: the headspace heating temperature is 90 ℃, the headspace heating time is 5min, the transmission line temperature is 100 ℃, and the headspace sampling needle temperature is 110 ℃.
The conditions of gas chromatography in the headspace-gas chromatography-mass spectrometry combined method comprise: the injection port temperature is 250 ℃, the injection port type is a split/non-split injection port, the split ratio of the injection port is 50:1, the carrier gas is high-purity helium, the carrier gas flow rate is 1mL/min, the temperature of a chromatographic column is kept for 3min at 35 ℃, the temperature is programmed to 250 ℃, the temperature is kept for 3min, the temperature rising speed is 10 ℃/min, and the temperature of a chromatographic mass spectrum connecting rod is 250 ℃;
the mass spectrum conditions in the headspace-gas chromatography-mass spectrometry combined method comprise: electron bombardment ionization source (EI source), electron energy is 70eV, and the temperature of mass spectrum ion source is 230 ℃; the mass spectrum acquisition type is full scan, and the mass range is m/z 20-200.
Example 3
(1) Preparation of a standard curve: weighing 1.5g of ethanol, placing the ethanol in a 10mL volumetric flask, adding deionized water to a constant volume to a scale mark, and preparing a standard mother solution with the ethanol content of 150 mg/mL;
diluting the standard mother liquor step by step into working curve standard point solutions with ethanol contents of 1.5mg/mL, 15mg/mL, 30mg/mL, 60mg/mL and 150mg/mL respectively by using deionized water, taking 100 mu L of the 5 working curve standard point solutions, placing the 5 working curve standard point solutions into respective 20mL headspace bottles, respectively detecting by adopting a headspace-gas chromatography-mass spectrometry combination method to respectively obtain a full-scanning total ion current chromatogram of the working curve standard point solutions, wherein the retention time of ethanol is shown in Table 1;
(2) respectively taking the content of ethanol in the standard solution as an X axis and the peak area of ethanol in the full-scanning total ion current chromatogram as a Y axis, drawing a standard curve (the linear range is shown in table 1), and fitting to obtain a regression equation (shown in table 1);
(3) and (3) placing 0.1 catalyst in a 10mL volumetric flask, adding water to a constant volume, and hydrolyzing at 25 ℃ for 15min under an ultrasonic condition to obtain a hydrolysate containing ethanol. And adding 100 mu L of hydrolysate into a 20mL headspace bottle, sealing, and detecting by using a headspace-gas chromatography-mass spectrometry method to obtain a full-scanning total ion current chromatogram of the hydrolysate of the catalyst 3 (as shown in figure 9).
(4) Substituting the peak area of the ethanol in the full-scanning total ion current chromatogram of the catalyst 3 hydrolysate into a regression equation to obtain the content of the ethanol in the hydrolysate, and then calculating to obtain the content of the ethoxy in the catalyst 3, wherein the calculation result is shown in table 1.
(5) Gradually diluting the 150mg/mL standard mother liquor in the step (1) to 0.1mg/mL, 0.05mg/mL and 0.001mg/mL, and taking the peak area signal-to-noise ratio of each substance as a detection limit, wherein the result shows that the peak area signal-to-noise ratio of each substance is more than 3 when the standard mother liquor is diluted to 0.001mg/mL, namely the detection limit is at least 0.001 mg/mL.
Wherein:
the conditions for headspace in the combined headspace-gas chromatography-mass spectrometry include: the headspace heating temperature was 80 ℃, the headspace heating time was 10min, the transfer line temperature was 90 ℃, and the headspace needle temperature was 100 ℃.
The conditions of gas chromatography in the headspace-gas chromatography-mass spectrometry combined method comprise: the injection port temperature is 200 ℃, the injection port type is a split injection port, and the split ratio of the injection port is 50:1, using high-purity helium as carrier gas, wherein the flow rate of the carrier gas is 1mL/min, keeping the temperature of a chromatographic column at 35 ℃ for 3min, raising the temperature to 200 ℃ by a program, keeping the temperature for 3min, and keeping the temperature at 10 ℃/min and the temperature of a chromatographic mass spectrometry connecting rod at 200 ℃;
the mass spectrum conditions in the headspace-gas chromatography-mass spectrometry combined method comprise: electron bombardment ionization source (EI source), electron energy 70eV, and mass spectrometry ion source temperature 230 ℃; the mass spectrometry acquisition type is a full scan. The mass range m/z is 20-400.
Comparative example 1
(1) Preparation of a standard curve: weighing 1.5g of ethanol, placing the ethanol in a 10mL volumetric flask, adding deionized water to a constant volume to a scale mark, and preparing a standard mother solution with the ethanol content of 150 mg/mL;
diluting the standard mother liquor step by deionized water into working curve standard point solutions with ethanol contents of 1.5mg/mL, 15mg/mL, 30mg/mL, 60mg/mL and 150mg/mL respectively, and detecting the 5 working curve standard points by adopting a gas chromatography-mass spectrometry combined method respectively;
(2) taking the content of the standard solution ethanol as an X axis and the peak area of the ethanol in the total ion current chromatogram as a Y axis, drawing a standard curve, and fitting to obtain a regression equation (see table 1);
(3) placing 0.1 catalyst 3 in a 10mL volumetric flask, adding water to a constant volume, hydrolyzing at 25 deg.C for 15min under ultrasonic condition to obtain ethanol-containing hydrolysate, filtering the hydrolysate with 0.22 μm filter membrane, and detecting the filtered hydrolysate by gas chromatography-mass spectrometry to obtain a full-scan total ion chromatogram (shown in figure 10) of the catalyst 3 hydrolysate;
(4) substituting the peak area of the ethanol in the full-scanning total ion current chromatogram of the catalyst 3 hydrolysate into a regression equation to obtain the content of the ethanol in the hydrolysate, and then calculating to obtain the content of the ethoxy in the catalyst 3, wherein the calculation result is shown in table 1.
Wherein:
the conditions of the gas chromatography-mass spectrometry combined method comprise: the automatic sample injector samples, and the sample injection volume is 1 uL, and the inlet temperature is 200 ℃, and the inlet type is reposition of redundant personnel/not reposition of redundant personnel inlet, and the inlet split ratio is 50:1, using high-purity helium as carrier gas, wherein the flow rate of the carrier gas is 1mL/min, keeping the temperature of a chromatographic column at 35 ℃ for 3min, raising the temperature to 200 ℃ by a program, keeping the temperature for 3min, and keeping the temperature at 10 ℃/min and the temperature of a chromatographic mass spectrometry connecting rod at 200 ℃; electron bombardment ionization source (EI source), electron energy 70eV, and mass spectrometry ion source temperature 230 ℃; the mass spectrometry acquisition type is a full scan. The mass range m/z is 20-400. The total ion flow chromatogram of the catalyst 3 hydrolysate is shown in fig. 10.
The peak area of the ethanol in the hydrolysate, and the calculated ethanol content in the hydrolysate and the alkoxy group content in the catalyst 3 are shown in table 1.
Comparative example 2
A standard curve was plotted and the alkoxy group content of catalyst 3 was determined as in example 3, except that the headspace conditions in the combined headspace-gas chromatography-mass spectrometry were as follows: the headspace heating temperature was 50 ℃, the headspace heating time was 5min, the transfer line temperature was 65 ℃, and the headspace needle temperature was 75 ℃.
The total ion flow chromatogram of the catalyst 3 hydrolysate is shown in fig. 11.
Gradually diluting 150mg/mL of standard mother liquor to 0.1mg/mL, 0.05mg/mL, 0.002mg/mL and 0.001mg/mL, and calculating the peak area signal-to-noise ratio of each substance to be greater than 3 as a detection limit, wherein the result shows that the peak area signal-to-noise ratio of each substance is greater than 3 when the standard mother liquor is diluted to 0.002mg/mL, and the peak area signal-to-noise ratio of each substance is less than 3 when the standard mother liquor is diluted to 0.001mg/mL, namely the detection limit is 0.002 mg/mL.
TABLE 1
Note: "ND" means not detected.
The results show that the method has high sensitivity (the detection limit of the standard solution can reach within 0.001mg/mL, and the detection limit of the alkoxy content can reach within 1 mu g/g in terms of conversion), high accuracy of the detection result (the actual recovery rate is high and can reach more than 95%), convenient operation and no need of complicated extraction steps. Whereas embodiments employing non-preferred conditions of the present invention have poor accuracy.
As can be seen from example 1 and comparative example 1, the detection result of example 1 using the headspace-gc-ms method is more accurate than that of comparative example 1 using the extraction-gc-ms method (conventional method).
As can be seen from example 3 and comparative example 2, the peak height of ethanol in the chromatogram of comparative example 2 in which the headspace condition in the headspace-gas chromatography-mass spectrometry was out of the range of the present invention was about 7X 106 About 9X 10 lower than the ethanol peak height in example 3 of the present invention6That is, the area of the ethanol peak in comparative example 2 is smaller than that of the ethanol peak in example 3, and the accuracy is lower; and the detection limit of comparative example 2, in which the headspace condition is not within the range of the present invention in the headspace-gas chromatography-mass spectrometry combination method, is 0.002mg/mL, which is higher than the detection limit of the method of the present invention.
The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.
Claims (10)
1. A method for detecting the content of alkoxy groups in a sample, the method comprising the steps of:
(1) respectively detecting standard solutions with different alcohol contents by a headspace-gas chromatography-mass spectrometry combination method to obtain chromatograms of the standard solutions;
(2) taking the content of alcohol in the standard solution as an X axis, and taking the peak area of the alcohol in the chromatogram of the standard solution as a Y axis to draw a standard curve;
(3) hydrolyzing the sample to obtain a hydrolysate containing alcohol, and detecting the hydrolysate containing alcohol by using a headspace-gas chromatography-mass spectrometry combined method under the same condition as the step (1) to obtain a chromatogram of the hydrolysate;
(4) quantifying the content of the alkoxy in the sample according to the peak area of alcohol in the chromatogram of the hydrolysate obtained in the step (3) and the standard curve in the step (2);
wherein the conditions for headspace in the combined headspace-gas chromatography-mass spectrometry comprise: the heating temperature of the headspace is 60-95 ℃, and the heating time of the headspace is 1-60 min.
2. The method of claim 1, wherein the conditions under which the headspace is performed in the combined headspace-gas chromatography-mass spectrometry comprise: heating the headspace at 80-95 deg.C for 3-15 min;
preferably, the conditions for conducting headspace in the combined headspace-gas chromatography-mass spectrometry further comprise: the temperature of the transmission line is 70-150 ℃, and the temperature of the headspace sample injection needle is 80-150 ℃;
more preferably, the conditions for conducting headspace in the combined headspace-gas chromatography-mass spectrometry further comprise: the temperature of the transmission line is 90-110 ℃, and the temperature of the headspace sampling needle is 100-120 ℃.
3. The method according to claim 1 or 2, wherein the alkoxy group is selected from one or more of alkoxy groups having 1 to 20 carbon atoms;
preferably, the alkoxy group contains one oxygen atom;
more preferably, the alkoxy group is selected from one or more of methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, n-pentoxy, isopentoxy, n-hexoxy, isohexoxy, n-heptoxy, isoheptoxy, n-octoxy, isooctoxy, n-nonoxy, isononyloxy, n-pentoxy, and isopentoxy.
4. The method according to any one of claims 1 to 3, wherein the different alcohol content standard solutions are formulated by a method comprising: a) preparing a standard mother solution with the alcohol content of 1-100mg/mL, preferably 1-25 mg/mL; b) diluting the standard mother liquor step by step into standard solutions with different alcohol contents;
preferably, the alcohol is selected from one or more of alcohols with the carbon number of 1-20;
preferably, the alcohol is a monohydric alcohol;
more preferably, the alcohol is selected from one or more of methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, n-pentanol, isopentanol, n-hexanol, isohexanol, n-heptanol, isoheptanol, n-octanol, isooctanol, n-nonanol, isononanol, n-decanol, isodecanol;
preferably, when the number of the alcohols is at least 2, the content of each alcohol is the same or different, and more preferably, the content of each alcohol is the same;
preferably, the solvents used to formulate and dilute the mother liquor are each independently selected from the group consisting of solvents miscible with the alcohol;
preferably, the solvent is selected from at least one of ethyl acetate, water, n-pentane, n-hexane, acetonitrile and acetone, more preferably ethyl acetate and/or water.
5. The method according to any one of claims 1 to 4, wherein the linear range of the standard curve is 0.001-100mg/mL, preferably 0.01-25 mg/mL; linear correlation coefficient > 0.99;
and/or when the standard solution contains at least 2 kinds of alcohol, respectively drawing a standard curve of each alcohol by taking the content of each alcohol in the standard solution as an X axis and taking the peak area of each corresponding alcohol in a total ion current chromatogram of the standard solution as a Y axis.
6. The method according to any one of claims 1 to 5, wherein the sample is an alkoxy group containing catalyst and/or an alkoxy group containing catalyst support, more preferably an alkoxy group containing Ziegler Natta catalyst and/or an alkoxy group containing Ziegler Natta catalyst support;
and/or, the conditions under which the hydrolysis is carried out include: the hydrolysis temperature is 0-50 ℃, preferably 15-30 ℃; the hydrolysis time is 5-30min, preferably 5-10 min;
preferably, the hydrolysis is carried out under the condition of ultrasound, and the power of the ultrasound is 40W-300W, more preferably 50W-100W;
preferably, the amount of water used for hydrolysis is 1-1000mL, more preferably 10-100mL, relative to 1g of sample.
7. The method according to any one of claims 1 to 6, wherein the headspace-gas chromatography-mass spectrometry combined method comprises a headspace vial sample volume of 2 to 1000 μ L, preferably 10 to 100 μ L.
8. The method of any one of claims 1-7, wherein the conditions for performing gas chromatography in the combined headspace-gas chromatography-mass spectrometry are: the temperature of the sample inlet is 180-280 ℃, the type of the sample inlet is a split/non-split sample inlet, the split ratio of the sample inlet is 5-100:1, the flow rate of the carrier gas is 0.5-1.5mL/min, the column temperature is kept for 0-5min at 35-50 ℃, the temperature is programmed to 200-280 ℃, the temperature is kept for 0-15min, the temperature programming speed is 2-50 ℃/min, and the temperature of the chromatographic mass spectrometry connecting rod is 180-280 ℃;
preferably, the conditions of the gas chromatograph are: the injection port temperature is 200-250 ℃, the injection port type is a split injection port, the split ratio of the injection port is 30-50:1, the flow rate of the carrier gas is 0.8-1.2mL/min, the column temperature is kept for 1-3min at 35-40 ℃, the temperature is programmed to 240-260 ℃ and kept for 0.3-10min, the temperature programming speed is 5-25 ℃/min, and the temperature of the chromatographic mass spectrum connecting rod is 200-260 ℃.
9. The method of any one of claims 1-8, wherein the conditions under which mass spectrometry is performed in the combined headspace-gas chromatography-mass spectrometry are: the mass spectrum ion source is an electron bombardment ionization source, the electron energy is 50-80eV, the temperature of the mass spectrum ion source is 200-280 ℃, preferably 200-250 ℃, and the mass spectrum collection type is full scanning and/or selective ion scanning;
or the mass spectrum acquisition type is full scanning and/or multi-reaction monitoring scanning;
preferably, the mass spectrometry acquisition types are full scan and selective ion scan;
alternatively, the mass spectrometry acquisition type is a selective ion scan.
10. Use of the method of any one of claims 1-9 for detecting the amount of alkoxy groups in a sample or for quality control of catalyst production.
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