JP2006145382A - Analysis method of anion component and analyzer therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a quantitative and qualitative simultaneous analysis method of anion components, especially halogenous acids and halogenide ions improved in sensitivity and precision, without being affected by other coexisting ions, and an analyzer therefor. <P>SOLUTION: In the analysis method of anion component, a sample containing the anion component is separated by an ion chromatograph and succeedingly detected by a time-of-flight mass spectrometer. The analyzer of the anion component is equipped with the ion chromatograph for separating the sample containing the anion component and the time-of-flight mass spectrometer coupled to the ion chromatograph so that the sample separated in the ion chromatograph is introduced directly. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a quantification method and a qualitative method for an anionic component, and an analysis apparatus therefor.

In recent years, methods for measuring anionic components, particularly halogen acids and halide ions present in rivers, air, foods, and the like have been sought.
For example, potassium bromate is widely known as an excellent bread dough improving agent. However, when potassium bromate is used in the bread production process, it is necessary to quantify the residual bromic acid in the bread, and a highly sensitive and simple method is required. In addition, it is necessary to analyze the halogen acid contained in the soil from the viewpoint of accumulation and contamination in the soil.
Furthermore, with the spread of advanced ozone treatment in tap water, high-sensitivity analysis is required for halogen acids generated as by-products, particularly bromic acid, due to carcinogenic problems. On May 30, 2003, the Ministry of Health, Labor and Welfare Ordinance No. 101 established a new water quality standard of 0.01 mg / L (10 ppb), but the measurement accuracy was around 1/10 of the standard value. Since the variation is determined to be within 10%, a method capable of stably measuring a 0.001 mg / L (1 ppb) solution is required. The method shown by the water supply method is an ion chromatograph-post column reaction method, which is a method in which bromic acid is converted into tribromide ions by the following reaction formula and detected by an ultraviolet absorption detector. An apparatus diagram of this method is shown in FIG.
This method is capable of selective detection of bromic acid and is a highly sensitive measurement method. However, since the baseline noise is large and the variation of the area value is recognized as 6 to 7%, a more stable analysis method is required. In addition, since the reaction liquid that flows in the post-column reaction uses 1M sulfuric acid or the like, the frequency of maintenance and inspection of the equipment increases. Therefore, a simpler analysis method is required.

On the other hand, there is a mass spectrometer as a detector capable of identifying a structure by molecular weight (Non-Patent Document 1). In recent years, LC-MS in which a liquid chromatograph and a mass spectrometer are connected online has been rapidly spread. Recently, a revolutionary method has been disclosed as an on-line connection of this mass spectrometer and an ion chromatograph (Non-patent Document 2). In this method, each component in tap water is separated by an ion chromatograph and connected to a quadrupole mass spectrometer on-line for detection. In this method, bromic acid can be quantified very easily without the need for complicated treatments such as pretreatment and post-reaction. However, with this method, the detection limit is as high as 1.28 ppb, and the variation coefficient of the area value is as large as 11.0%, so it is difficult to put it to practical use in terms of sensitivity and accuracy. Furthermore, when detecting with a mass spectrometer, it can be expected to perform qualitative analysis simultaneously with quantification. If qualitative analysis can be performed at the same time, it is possible to distinguish and confirm the target anion component, in particular, ions derived from halogen acids and halide ions and ions derived from contaminants. Therefore, it is very effective. However, in the quantification (SIM) mode of a scanning mass spectrometer such as a quadrupole type or a magnetic field type, since only the selected ions do not reach the detector, a full spectrum cannot be obtained, and high-sensitivity qualitative analysis is difficult. It is. In a time-of-flight mass spectrometer, all ions reach the detector, so that a full spectrum can be obtained and the mass axis is highly stable. Until now, there has been no method for analyzing by connecting an ion chromatograph and a time-of-flight mass spectrometer.
“What is Mass Spectrometry”, edited by Hirayama et al., Published by Japan Mass Spectrometry Society “Journal of Chromatography A”, 2002, 956 p. 245-254

  An object of the present invention is to provide a quantitative and qualitative simultaneous analysis method with improved sensitivity and accuracy without being affected by other coexisting ions in a method for measuring anion components, particularly halogen acids and halide ions. It is. Furthermore, it is providing the analyzer of an anion component.

  As a result of repeated trials to solve the above problems, the present inventor analyzed the anion component with high sensitivity and high accuracy by separating the sample with an ion chromatograph and subsequently detecting it with a time-of-flight mass spectrometer. Has been found to be possible, and that quantitative and qualitative analysis can be performed simultaneously, and the present invention has been achieved.

That is, the above object is achieved by the following method.
(1) A method for analyzing an anionic component, wherein a sample having an anionic component is separated by an ion chromatograph and subsequently detected by a time-of-flight mass spectrometer.
(2) The method for analyzing an anion component according to the above (1), wherein the ionization method of the time-of-flight mass spectrometer is an electrospray ionization method or an atmospheric pressure chemical ionization method.
(3) The method for analyzing an anionic component according to the above (1), wherein the anionic component is bromic acid.
(4) The method for analyzing an anionic component according to (1), wherein the quantitative analysis and the qualitative analysis are simultaneously performed.
(5) an ion chromatograph for separating a sample having an anion component, and a time-of-flight mass spectrometer connected to the ion chromatograph so that the sample separated in the ion chromatograph is directly introduced. An anion component analyzer equipped.

  According to the present invention, it is possible to quantify anionic components, particularly halogen acids and halide ions, with high sensitivity and high accuracy, and at the same time, qualitative analysis can be performed.

The present invention is described in more detail below.
The anion component in the present invention can be analyzed as long as it becomes an anion in water, but is preferably hypochlorous acid, chlorous acid, chloric acid, perchloric acid, hypochlorous acid, Halogen acids such as bromic acid, bromic acid, perbromic acid, hypoiodic acid, iodic acid, iodic acid, periodic acid; halide ions such as fluoride ion, chloride ion, bromide ion, iodide ion Kind. Among these, chloric acid, bromic acid, iodic acid, bromide ion, and iodide ion are more preferable, and bromic acid is particularly preferable.

Next, an apparatus constituting the present invention will be described. FIG. 1 is a configuration diagram of an analyzer according to the present invention. FIG. 2 is a device diagram of a time-of-flight mass spectrometer.
The apparatus of the present invention includes an ion chromatograph including an injector 1, a liquid feed pump 2, a separation column 3, and a suppressor 4, a cation detection means 5, a valve 11, a time-of-flight mass spectrometer 12, a detector 5 and a valve 11. And a tube 10 connecting the valve 11 and the time-of-flight mass spectrometer 12. Even if the cation detecting means 5 and the valve 11 are not provided, there is no problem in the analysis, but by checking with the detecting means 5, it is possible to prevent unnecessary cations from being injected into the mass spectrometer. It is more preferable to install the detection means 5 and the valve 11 from the viewpoint of maintenance of a very expensive mass spectrometer.

  As an outline of the apparatus of the present invention, first, a buffer solution is flowed from the buffer solution supply unit 7 by the liquid feed pump 2, a sample is injected into the injector 1, and the target anion and other ions are separated by the separation column 3. Next, the eluent and various cations derived from the sample are converted into hydrogen ions through the suppressor 4, and it is further confirmed whether or not these cations are converted into hydrogen ions through the detection means 5. When more than an allowable amount of cations passes through the detection means 5, the valve 11 is switched to send the eluent to the waste liquid tank. By monitoring the cations by the detection means 5, it is possible to prevent clogging of the first orifice 15 described later in the time-of-flight mass spectrometer 12 that occurs when the suppressor 4 does not sufficiently convert cations to hydrogen ions. In addition, when the suppressor 4 is not functioning normally, anion and cation in the eluent form additional ions to inhibit ionization of the sample, so that measurement sensitivity with a mass spectrometer is lowered. Since it is possible to determine whether or not the suppressor 4 is functioning normally by monitoring with the detecting means 5, it is desirable to install the detecting means 5 and the valve 11 from this point.

The time-of-flight mass spectrometer 12 is roughly composed of an ionization unit and a mass analysis unit.
The ionization section is provided with a capillary 13 for introducing an eluent from the ion chromatograph side and a desolvation chamber 14 that can be adjusted to a high temperature.
In the mass analyzer, ions are accelerated by the first orifice 15 serving as the entrance of the mass analyzer, the ring lens 16, the second orifice 17, the ion guide 18 that can be set to a predetermined voltage, and the acceleration voltage. A pusher 19, a flight tube 20, and an ion detector 22 are provided.

After separation by ion chromatography, the eluent containing the target anion component is introduced into the time-of-flight mass spectrometer 12. First, in the ionization section, the eluent passes through the capillary 13 and is volatilized in the solvent-removing chamber 14 set at a high temperature, and becomes a fine droplet by the nitrogen stream in the capillary 13 and is ionized by an ionization method described later. The ionized anion component is introduced into the time-of-flight mass analyzer through the first orifice 15 which is an entrance to the mass analyzer.
The ions introduced into the mass analysis unit are guided to the pusher 19 through the ring lens 16, the second orifice 17, and the ion guide 18. The ring lens 16, the second orifice 17, and the ion guide 18 have a function of roughly converging each ion. The ring lens 16 and the second orifice 17 have a function of efficiently guiding ions to the ion guide 18 by applying a voltage to the ions that have passed through the first orifice 15.
The ion guide 18 is composed of a quadrupole and has a function of adjusting ions to the same kinetic energy over all mass numbers by applying a high-frequency voltage. If ions are not adjusted to the same kinetic energy, the time of flight of each ion is shifted, and the accuracy of mass spectrometry is reduced. If the high frequency voltage of the ion guide 18 is set low, it is optimized to the low mass side and it becomes difficult to detect ions on the high mass side, and if it is set high, it is optimized to the high mass side and ions on the low mass side are difficult to detect. Therefore, it is necessary to set an optimum voltage for the mass-to-charge ratio of ions to be measured.

  Next, the ions are accelerated by the pusher 19 at a constant acceleration voltage, pass through the flight tube 20 in a time proportional to the mass-to-charge ratio (m / z), and reach the ion detector 22. Since the time-of-flight mass spectrometer has a higher resolution as the length of the flight tube 20 increases, a reflector 21 is disposed at the bottom of the flight tube 20 to reflect the ions and increase the flight distance, thereby increasing the resolution. Measurement is possible. Finally, the mass-to-charge ratio of the ions can be measured by measuring the time until the ions reach the detector.

As ionization methods for introducing the eluent flowing from the ion chromatograph into the mass spectrometer, electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI), and atmospheric pressure photoionization (APPI) , Electron ionization method (EI), fast atom bombardment method (FAB) and the like. Any of these methods can be used in the present invention, but electrospray ionization and atmospheric pressure chemical ionization are preferred.
In the electrospray ionization method, as shown in FIG. 3, charged droplets are formed by spraying dry nitrogen 23 on the tip of the capillary 13 from which the eluent containing the sample flows out by applying a high voltage of several thousand volts from the power supply 24. And the droplets are dried to introduce ions into the mass spectrometer. The characteristics of the electrospray ionization method are as follows. (I) The molecular weight is easy to confirm because of soft ionization, (ii) multivalent ions are generated, (iii) from low mass compounds having a molecular weight of 100 or less to high mass compounds exceeding 100,000, ( iv) It can be measured at a wide range of flow rates from 1 μL / min to 1.5 mL / min, and (v) a compound having a polar functional group or an ionic compound can be measured with high sensitivity.
In the atmospheric pressure chemical ionization method, as shown in FIG. 4, the capillary 13 through which the eluent containing the sample flows out is sprayed with dry nitrogen 23 and heated at a high temperature of 400 to 500 ° C. to forcibly evaporate the eluent. Then, ions are generated using the discharge by the corona discharge needle electrode 25 and introduced into the mass spectrometer. The characteristics of the atmospheric pressure chemical ionization method are as follows. (I) The molecular weight is easy to confirm because of soft ionization. (Ii) It can be measured over a wide range of flow rates from 0.1 mL / min to 2.0 mL / min. (Iii) Suitable for measurement of compounds having a molecular weight of 1500 or less. (Iv) A compound having a medium polarity can be measured with high sensitivity.

  The separation column 3 of the ion chromatograph used in the present invention is a type in which a polymer gel is packed with a filler bonded with a basic group, and the filler used is a type that normally separates anions used for ion chromatography. Anything can be used. Specifically, the polymer gel may be a simple substance or a copolymer such as ethyl vinyl benzene, divinyl benzene, stil vinyl benzene, or hydrophilic polymer gel. Examples of basic groups include quaternary alkylamines, quaternary alkanolamines, and the like. Preferred columns in the present invention include Shodex SI-50 manufactured by Showa Denko, TSKgel SuperIC-AP manufactured by Tosoh, IonPac AS12A manufactured by Dionex, and the like. The length of the separation column 3 is usually 10 to 500 mm, preferably 30 to 300 mm, more preferably 50 to 250 mm. The inner diameter of the separation column 3 is usually 0.5 to 10.0 mm, preferably 0.8 to 8.0 mm, and more preferably 1.0 to 6.0 mm. The temperature of the separation column 3 is usually set to 10 ° C to 70 ° C, preferably 15 ° C to 60 ° C, more preferably 20 ° C to 50 ° C.

  As the eluent used in the present invention, any buffer aqueous solution usually used for ion chromatography can be used, but preferably sodium bicarbonate, sodium carbonate, sodium hydroxide, potassium bicarbonate, potassium carbonate, hydroxide It is a buffered aqueous solution in which potassium is single or mixed. Further, the eluent may have a single concentration or a gradient with different concentrations. The flow rate of the eluent in the ion chromatograph is usually 0.01 to 2.0 mL / min, preferably 0.05 to 1.8 mL / min, more preferably 0.1 to 1.5 ml / min. Specifically, when a semi-micro column having an inner diameter of 2.0 mm is used, the electrospray ionization method is performed at 0.1 to 0.5 ml / min with good ionization efficiency.

Any suppressor 4 can be used as long as it is a type that converts a cation normally used in an ion chromatograph to a hydrogen ion, but is preferably an ion exchange membrane type or an ion exchange resin type. In the present invention, it is preferable to use an eluent having a cation concentration of 1 ppm or less that has passed through a suppressor in order to connect to a mass spectrometer.
As the detection means 5, an ion conductivity meter, an electrochemical detector, an ion meter such as a pH meter, a pH test paper, and a sodium meter can be used, but preferably an ion chromatograph or a high performance liquid chromatograph (HPLC). It is an electrical conductivity detector that is normally used. The value (upper limit) monitored by the electrical conductivity detector is determined by the electrical conductivity of the anion derived from the buffered aqueous solution as the eluent, and varies depending on the type and concentration of the eluent. For example, a 1 mM Na ₂ CO ₃ solution has a value of 25 μS or less, and a 10 mM Na ₂ CO ₃ solution has a value of 50 μS or less. When the electrical conductivity exceeds the upper limit, it is considered that the suppressor does not sufficiently convert the cation to the hydrogen ion, which is a measure of whether the suppressor function is deteriorated.

  After separation with an ion chromatograph, the eluent containing the target anion component may be taken out once, or the ion chromatograph and the time-of-flight mass spectrometer 12 are connected with a tube to contain the anion component after separation. The eluent may be continuously introduced into the time-of-flight mass spectrometer 12 for measurement. Preferably, the ion chromatograph and the time-of-flight mass spectrometer 12 are connected, and the separated anion component is directly introduced into the time-of-flight mass spectrometer 12 for measurement. Therefore, the ion chromatograph and the time-of-flight mass spectrometer 12 are preferably connected so that the sample separated in the ion chromatograph is directly introduced. At that time, the ion chromatograph and the time-of-flight mass spectrometer 12 are connected by, for example, a tube 10. The tube 10 can be made of a commonly used polymer resin, stainless steel, Teflon or the like. A PEEK tube made of polymer resin or a stainless steel tube is preferable. The tube 10 has an inner diameter of usually 0.01 to 1.00 mm, preferably 0.05 to 0.80 mm, more preferably 0.10 to 0.50 mm.

In the electrospray ionization method, the needle voltage by the power source 24 is usually 0 to −5000V, preferably −200 to −4000V, more preferably −500 to −3000V. In the atmospheric pressure chemical ionization method, the corona voltage applied to the corona discharge needle electrode 25 is usually 0 to −6000V, preferably −500 to −5000V, more preferably −1000 to −5000V.
The temperature of the desolvation chamber 14 is usually 30 to 750 ° C, preferably 70 to 700 ° C, more preferably 100 to 600 ° C. The temperature of the 1st orifice 15 is 30-600 degreeC normally, Preferably it is 70 to 400 degreeC, More preferably, it is 100 to 300 degreeC.
The voltage of the ion guide 18 is 10-5000V normally, Preferably it is 50-4000V, More preferably, it is 100-3000V. Since the measurement range of the mass to charge ratio is determined by the voltage of the ion guide 18, the voltage setting of the ion guide 18 is important. For example, in the analysis of bromic acid, the optimum value of the voltage of the ion guide is 500 to 1000 V, and there is an optimum value for each of the other anions.
The potential difference (second orifice voltage) between the ion guide 18 and the second orifice 17 is usually 0 to −200 V, preferably 0 to −150 V, and more preferably 0 to −100 V. The potential difference (first orifice voltage) between the first orifice 15 and the second orifice 17 is usually 0 to −300V, preferably 0 to −200V, more preferably 0 to −150V. The potential difference (ring lens voltage) between the first orifice 15 and the ring lens 18 is usually 0 to −200V, preferably 0 to −150V, and more preferably 0 to −100V.

  The sample to be measured is pretreated as necessary depending on its shape. For example, water samples such as tap water and river water can be directly injected, but preferably measured using a filter paper or passed through a disposable filter. Solid materials such as soil and food are extracted with ultrapure water and then filtered. In this case, centrifugation may be performed in the middle as necessary. The injection amount of these samples is usually 0.1 to 500 μL, preferably 1 to 400 μL, more preferably 10 to 300 μL.

Examples using the analysis method of the present invention will be given below, but the present invention is not limited thereto. The area value described in each example refers to the area of a peak in a mass chromatogram of ions (including fragment ions) derived from the anion component to be measured.
In addition, the measuring apparatus used in the examples is a product manufactured by Tosoh Corporation (IC-2001) in which a pump, an autosampler, a column oven, and an electric conductivity detector are integrated as an ion chromatograph, and JEOL Ltd. as a mass spectrometer. A manufactured product (AccuTOF) was used. The measurement conditions of each device are as follows.
Ion chromatograph measurement conditions (1): Separation column Shodex SI-50 manufactured by Showa Denko (inner diameter: 2.0 mm, length: 150 mm): column temperature 40 ° C .: eluent 1 mM Na ₂ CO ₃ : flow rate 0.3 mL / min : Injection volume 50 μL
Ion chromatographic measurement conditions (2): Separation column Shodex SI-50 manufactured by Showa Denko (inner diameter: 2.0 mm, length: 150 mm): column temperature 40 ° C .: eluent A 1 mM Na ₂ CO ₃ , B 10 mM Na ₂ CO ₃ A / B = 100/0 => 0/100 (2 to 8 minutes linear gradient): Flow rate 0.3 mL / min: Injection volume 50 μL
Measurement conditions of mass spectrometer: Desolvation chamber temperature 500 ° C .: Temperature of first orifice 150 ° C .: Needle voltage −1500 V: First orifice voltage −50 V: Second orifice voltage −5 V: Ring lens voltage −5 V: Ion guide voltage 750 V

Preparation of bromic acid standard solution Sodium bromate was dried at 110 ° C. for 2 hours, allowed to cool in a silica gel desiccator for 1 hour, weighed 1.180 g, put into a 1000 mL volumetric flask, and made exactly 1000 mL with ultrapure water. A 1000 ppm solution was prepared. Next, 10 mL of the 1000 ppm solution was weighed, put into a 100 mL volumetric flask, made exactly 100 mL with ultrapure water, and a 100 ppm solution was prepared. In the same manner, 10 ppm solution, 1 ppm solution, 100 ppb solution, 10 ppb solution, 5 ppb solution, 1 ppb solution, 500 ppt solution, 100 ppt solution, and 50 ppt solution were prepared, and these were used as the bromate standard solution.

Preparation of mixed standard solution of halogen acids and halide ions Potassium chlorate, sodium bromate, sodium iodate, sodium bromide and potassium iodide were dried at 110 ° C. for 2 hours and further allowed to cool in a silica gel desiccator for 1 hour. Then, 1.469 g of potassium chlorate, 1.180 g of sodium bromate, 1.131 g of sodium iodate, 1.288 g of sodium bromide, 1.308 g of potassium iodide, put in a 1000 mL volumetric flask, and with ultrapure water To make exactly 1000 mL, a 1000 ppm solution was prepared. Next, 10 mL of the 1000 ppm solution was weighed, put into a 100 mL volumetric flask, made exactly 100 mL with ultrapure water, and a 100 ppm solution was prepared. In the same manner, 10 ppm solution, 1 ppm solution, 100 ppb solution, 10 ppb solution, 5 ppb solution, 1 ppb solution, 500 ppt solution, 100 ppt solution, and 50 ppt solution were prepared, and these were used as a mixed standard solution of halogen acids and halide ions.

Example 1 Analysis of Bromate Standard Solution Using the previously prepared bromate standard sample, measurement was performed under ion chromatographic method measurement conditions (1) to prepare a calibration curve. The analysis result chart is shown in FIG. 5, and the calibration curve is shown in FIG. The relative standard deviation at n = 7 of the area value of the 1 ppb solution of bromic acid standard sample by this method was 2.8%. Table 1 shows the results of repeated reproducibility of 1 ppb bromate solution. The value of the electrical conductivity detector at the time of measurement of Example 1 was 6.8 μS.

  From the results of Table 1, the bromic acid analysis method according to the present invention is a highly effective bromic acid analysis method, capable of high-sensitivity and high-accuracy analysis as compared with the ion chromatograph-post column reaction method. It can be said. In addition, this method not only satisfies the condition of an analytical method in which the reproducibility of a 1 ppb solution stipulated by the Waterworks Law is within 10%, but it can be quantified up to 50 ppt. Applicable to analysis of bromic acid.

Example 2 Analysis of bromic acid in tap water Tap water was collected and passed through a 0.45 μm disposable filter to make a sample solution 1 and analyzed under ion chromatography measurement conditions (1). Next, 1 ppb of bromic acid was added to the tap water to obtain a sample solution 2, and the analysis was performed in the same manner. The concentration was calculated from the area value obtained by the measurement using the calibration curve of FIG. The obtained full spectrum was the same as that of the bromic acid standard solution. The analysis result chart is shown in FIG. 7, and the accurate mass number measurement result is shown in FIG. The value of the electrical conductivity detector at the time of measurement was 7.0 μS.

Example 3 Analysis of bromate in river water Analysis was performed under the same conditions as in Example 2 except that the sample to be measured was changed to river water, and each value was calculated in the same manner. Moreover, what added 1ppb of bromic acid to this sample was prepared, and analyzed similarly. All obtained full spectra were the same as the bromic acid standard solution. The value of the electrical conductivity detector was 6.9 μS.

Example 4 Analysis of Bromate in Soil The soil was collected, immersed in 5 times the amount of ultrapure water, and stirred for 1 hour. After separating soil and water by centrifugation, the supernatant was passed through a 0.45 μm disposable filter as a sample solution. Using this sample solution, analysis was performed under the same conditions as in Example 2, and each value was calculated in the same manner. Moreover, what added 1ppb of bromic acid to this sample was prepared, and analyzed similarly. As a result of analysis with a mass spectrometer, bromic acid was not detected in the sample solution itself, but the full spectrum obtained for the sample solution added with 1 ppb of bromic acid was the same as that of the bromic acid standard solution. . The value of the electrical conductivity detector was 7.3 μS.
The results of quantitative analysis of Examples 2 to 4 are shown in Table 2, and the results of qualitative analysis of Examples 2 and 3 are shown in Table 3. In the case of bromic acid, the mass spectrometer usually detects two peaks derived from bromine having a mass number of 79 and 81, so each value is shown in Table 3. In Table 3, the mass number error (millimeter unit; mmu) and the error relative to the molecular weight (value obtained by dividing the mass number error by the molecular weight; ppm) are shown.

Comparative Example Using a 1 ppb standard solution of bromic acid as a sample, analysis was performed by the method described in Ordinance No. 101 of the Ministry of Health, Labor and Welfare on May 30, 2003. The analysis conditions are as follows.
Separation column: Super IC-AP manufactured by Tosoh (inner diameter: 4.6 mm, length: 150 mm), column temperature: 40 ° C., eluent: 0.3 mM Na ₂ B ₄ O ₇ +1.7 mM NaHCO ₃ +2.6 mM Na ₂ CO ₃ , flow rate: 0.8 mL / min, injection volume: 300 μL
Post-column reaction conditions: (Reaction solution A) 1.5 M KBr + 1.0 MH ₂ SO ₄ , flow rate 0.32 mL / min, (Reaction solution B) 1.2 mM NaNO ₂ , flow rate 0.16 mL / min
Mixing coil: 0.5mm inner diameter, 0.5m length
Reaction coil: inner diameter 0.5mm, length 2.0m
Ultraviolet detector wavelength: 268 nm
A chart of the analysis results of the 1 ppb bromate solution is shown in FIG.

  From the above results, in Examples 2 to 4, since the bromine acid addition recovery rate is very good, it is possible to measure even a sample with many impurities. Further, comparing the chart of the comparative example (FIG. 9) and the chart of the example (FIG. 5), it is clear that the accuracy of the analysis method of the present invention is high. Furthermore, it is possible to obtain an accurate mass number from the obtained full spectrum, and it has a very effective constant performance. Since the present invention can perform quantification and qualitative simultaneously, there is no possibility that a peak other than bromic acid is mistakenly assigned, so that it is considered to be a highly reliable analytical method.

Example 5 Analysis of Halogen Acids and Halide Ions Mixed Solution Using the previously prepared mixed standard solution of halogen acids and halide ions as a sample, analysis was performed under ion chromatographic measurement conditions (2). A calibration curve was prepared for anions. In addition, the value of the electrical conductivity detector increased as the Na ₂ CO ₃ concentration increased in the gradient analysis, and was 7.0 to 21.4 μS.

Example 6 Simultaneous Analysis of Tap Water Tap water was collected, passed through a 0.45 μm disposable filter to make a sample solution, analyzed for each anion under the same conditions as in Example 5, and each of the calibration curves prepared in Example 5 The anion concentration was calculated. In addition, the same full spectrum as that of the standard product was obtained for any anion. The results of Example 6 are shown in Table 4. In addition, the value of the electrical conductivity detector at the time of measurement was 7.1 to 22.0 μS.

Example 7 Simultaneous analysis of river water River water was sampled and passed through a 0.45 μm disposable filter to make a sample solution, and each anion was analyzed under the same conditions as in Example 5. From the calibration curve created in Example 5, The concentration of each anion was calculated. For all anions, the same full spectrum as the standard product was obtained. The results of Example 7 are shown in Table 5. The value of the electrical conductivity detector at the time of measurement was 6.8 to 22.5 μS.

  From the results of Tables 4 and 5, it can be seen that the analysis method of the present invention can simultaneously analyze many kinds of compounds and can simultaneously perform quantitative and qualitative analysis with high sensitivity. Therefore, the analysis time can be significantly shortened compared with the case where each anion is analyzed.

It is an apparatus diagram of an ion chromatograph-time-of-flight mass spectrometer. It is an apparatus figure of a time-of-flight mass spectrometer (TOF / MS). It is a conceptual diagram of the electrospray ionization method. It is a conceptual diagram of an atmospheric pressure chemical ionization method. It is a mass chromatogram of a bromate standard sample measured with an ion chromatograph-time-of-flight mass spectrometer. It is a figure of the absolute calibration curve of the bromic acid standard sample measured with the ion chromatograph-time-of-flight mass spectrometer. It is the mass chromatogram of the sample which added 1ppb bromic acid to the tap water and tap water which were measured with the ion chromatograph-time-of-flight mass spectrometer. It is an accurate mass spectrum of bromic acid in tap water measured with an ion chromatograph-time-of-flight mass spectrometer. It is a mass chromatogram of a bromic acid standard sample measured by an ion chromatograph-post column reaction method. It is a mass chromatogram of iodide ion in tap water and river water in a simultaneous analysis method measured with an ion chromatograph-time-of-flight mass spectrometer. It is the exact mass spectrum of the iodide ion in river water by the simultaneous analysis method measured with the ion chromatograph-time-of-flight mass spectrometer. It is an apparatus diagram of an ion chromatograph-post column reaction method.

Explanation of symbols

1: Injector 2: Liquid feed pump 3: Separation column 4: Suppressor 5: Cation detection means 6: Ultraviolet absorption detection group 7: Eluent supply unit 8: Reaction liquid A
9: Reaction solution B
10: Peak tube 11: Valve 12: Time-of-flight mass spectrometer 13: Capillary (needle)
14: Desolvation chamber 15: First orifice 16: Ring lens 17: Second orifice 18: Ion guide 19: Pusher 20: Flight tube 21: Reflector 22: Ion detector 23: Dry nitrogen 24: Power supply 25: For corona discharge Needle electrode

Claims (5)

  A method for analyzing an anionic component, wherein a sample having an anionic component is separated by an ion chromatograph and subsequently detected by a time-of-flight mass spectrometer.   2. The method for analyzing an anion component according to claim 1, wherein the ionization method of the time-of-flight mass spectrometer is an electrospray ionization method or an atmospheric pressure chemical ionization method.   The method for analyzing an anionic component according to claim 1, wherein the anionic component is bromic acid.   The method for analyzing an anion component according to claim 1, wherein the quantitative analysis and the qualitative analysis are performed simultaneously.   An anion component comprising: an ion chromatograph for separating a sample having an anion component; and a time-of-flight mass spectrometer connected to the ion chromatograph so that the sample separated in the ion chromatograph is directly introduced Analysis equipment.

Images