WO2020213209A1

WO2020213209A1 - Gas chromatography sample preparation method and analysis method

Info

Publication number: WO2020213209A1
Application number: PCT/JP2019/048544
Authority: WO
Inventors: 結実海野; 川名　修一; 藤原　賢; 尾島　典行
Original assignee: 株式会社島津製作所
Priority date: 2019-04-18
Filing date: 2019-12-11
Publication date: 2020-10-22
Also published as: JP2022088694A

Abstract

This gas chromatography sample preparation method comprises: performing at least one of measuring the pH of at least one from among a sample solution containing a sample, a reference solution containing a known concentration of a reference material, and a mixture of the sample solution and the reference solution, and analyzing a solution containing a molecule of the same type as the analyte and the reference material; preparing a sample for derivatization on the basis of the measured pH or the data obtained from said analysis; and bringing the sample for derivatization into contact with a derivatizing agent in the presence of a base. If the analysis is to be performed, the solution that has been brought into contact with the derivatization agent in the presence of the base is at least subjected to gas chromatography.

Description

Preparation method and analysis method of sample for gas chromatography

The present invention relates to a method for preparing and analyzing a sample for gas chromatography.

In the preparation of a sample for gas chromatography, the molecules contained in the sample are derivatized. In such derivatization, it is possible to stabilize a specific atom or group of atoms in the molecule so that the peak corresponding to the molecule in the chromatogram does not split, or to make the molecule more volatile to increase the sensitivity. Will be. In Non-Patent Document 1, oxime formation is performed by adding a pyridine solution in which methoxyamine hydrochloride is dissolved to a sample.

The efficiency of derivatization of molecules contained in the sample may vary depending on the sample preparation method.

The first aspect of the present invention is to prepare a sample solution containing a sample, to prepare a standard solution containing a standard substance having a known concentration, the sample solution, the standard solution, the sample solution, and the sample solution. At least one measurement of pH with a mixed solution obtained by mixing the standard solution, and analysis of a solution containing the same type of molecule as the analysis target and the standard substance, and the measured pH. Alternatively, a derivatization sample is prepared based on the data obtained by the analysis, and the derivatization sample is brought into contact with a derivatizing agent in the presence of a base to prepare a gas chromatography sample. The present invention relates to a method for preparing a sample for gas chromatography in which at least gas chromatography is performed on the solution contacted with the derivatizing agent in the presence of the base when the analysis is carried out.
A second aspect of the present invention relates to an analysis method comprising preparing a gas chromatography sample by the method for preparing a gas chromatography sample of the first aspect, and subjecting the gas chromatography sample to at least gas chromatography. ..

According to the present invention, it is possible to reduce variations in derivatization efficiency with respect to molecules contained in the sample.

FIG. 1 is a conceptual diagram for explaining a method for preparing a sample for gas chromatography according to an embodiment. FIG. 2 is a flowchart showing the flow of the analysis method according to the embodiment. FIG. 3 is a flowchart showing the flow of the analysis method according to the modified example. FIG. 4 is a table showing the peak area in the chromatogram obtained by gas chromatography / mass spectrometry in the examples. FIG. 5 is a graph showing the peak area of the peak corresponding to pyruvic acid in the chromatogram obtained by gas chromatography / mass spectrometry in the example.

Hereinafter, a mode for carrying out the present invention will be described with reference to the drawings.

-First Embodiment-
In the method for preparing a sample for gas chromatography of the present embodiment, at least a solution containing a sample to be analyzed (hereinafter referred to as an analysis target sample), a solution containing a standard substance, and a solution containing the analysis target sample and the standard substance. One pH measurement is performed, and a sample to be derivatized is prepared based on the measured pH. Hereinafter, the solution containing the sample to be analyzed is referred to as a sample solution, the solution containing the standard substance is referred to as a standard solution, and the solution containing the sample to be analyzed and the standard substance is referred to as a mixed solution.

FIG. 1 is a conceptual diagram showing the preparation of a gas chromatography sample of the present embodiment. Hereinafter, gas chromatography is abbreviated as GC. The sample solution Sn contains the sample S to be analyzed. When the molecules constituting the sample S to be analyzed are quantified by GC, the sample Sg for GC is prepared by derivatization from the mixed solution M containing the standard solution Ss containing the internal standard Is and the sample solution Sn. In other words, the mixed solution M is a sample for derivatization. In the analysis of the GC sample Sg containing GC, the concentration from the detection intensity of the molecule, etc. Can be calculated. In the following, the detection intensity refers to the magnitude of the detection signal corresponding to the molecule.
A standard sample for GC including an external standard (not shown) may be prepared and subjected to GC to prepare calibration data such as a calibration curve or a relative response coefficient, and quantification may be performed using this calibration data. Further, both the external standard and the internal standard may be used for quantification.

In GC, a plurality of molecules are usually separated and detected. The upper part of FIG. 1 shows the flow of preparation when a plurality of standard solutions Ss are mixed to prepare a sample Sgx for GC. Standard solutions Ss1, Ss2 and Ss3 containing the internal standards Is1, Is2 and Is3 corresponding to the three types of molecules contained in the sample S to be analyzed are prepared. The sample solution Sn and the standard solutions Ss1, Ss2 and Ss3 are mixed to prepare a mixed solution Mx containing the sample S to be analyzed and the internal standards Is1, Is2 and Is3 (arrow A1).
Although FIG. 1 shows an example in which three types of internal standards Is1, Is2, and Is3 are prepared for each of the three types of molecules, the number of internal standards prepared is not particularly limited. In addition, a plurality of molecules may be quantified using one internal standard Is.

The mixed solution Mx is subjected to a derivatization reaction (arrow A2). In the example of the derivatization reaction shown in FIG. 1, methoxymation is carried out as the first reaction by contact between the mixed solution M and the methoxymizing agent in the presence of a base (arrow A3). After the mixed solution Mx is dried, a solution containing a methoxymating agent using pyridine as a base as a solvent can be added to carry out the first reaction. Modulation stabilizes the atoms or groups in the molecule so that unwanted reactions do not occur in the preparation or analysis of the GC sample Sg. Pyridine is used to open the cyclic molecule and treat it so that the peak does not split in the chromatogram. Then, trimethylsilylation (hereinafter referred to as TMSification) is performed as a second reaction by contact with a trimethylsilylating agent (hereinafter referred to as TMS agent). The second reaction can be carried out by adding a TMS agent to the reaction solution of the first reaction while leaving pyridine as a base. The TMS formation makes the molecule more volatile and can increase the sensitivity in analysis involving GC.

The lower part of FIG. 1 shows the flow of preparation when preparing the GC sample Sg1 without mixing the standard solutions Ss with each other. The sample solution Sn and the standard solution Ss1 are mixed to prepare a mixed solution M1 for quantifying the molecule corresponding to the internal standard Is1 (arrow A5). It is assumed that the mixed solution M1 is prepared without using the standard solution Ss other than the standard solution Ss1. The mixed solution M1 is subjected to a derivatization reaction (arrow A6), ie, in the example of FIG. 1, methoxymization (arrow A7) and TMS formation (arrow A8).

The inventors found that when the pH of the mixed solution Mx and the pH of the mixed solution M1 were different (arrow A9), the efficiency of derivatization of the molecules contained in these solutions was different (arrow A10), and the analysis including GC was performed. It was found that the strength is also different. In particular, the pH of the standard solution Ss may differ significantly depending on the properties of the molecules constituting the internal standard Is. Therefore, when a plurality of standard solution Ss are mixed to prepare a GC sample Sgx as shown in the upper part of FIG. 1, and when a GC sample Sg1 is prepared without mixing the standard solution Ss as shown in the lower part of FIG. It was found that even when the same amount of molecules are subjected to analysis containing GC, the detection intensity of the molecules is different.

In the method for preparing a GC sample of the present embodiment, the pH of at least one of the sample solution Sn, the standard solution Ss, and the mixed solution M is measured. The method for measuring pH is not particularly limited, and a part of these solutions is transferred to another container or the like, and a pH measuring device such as a pH meter, pH test paper, or a reagent whose color changes depending on pH is used. Can be measured.

Based on the measured pH, the pH of the mixed solution M is adjusted to be comparable in a series of analyzes performed under the same analytical conditions, or to be comparable to the analysis to be compared. The term "similar" as used herein means that the pH difference is appropriately set to less than 2, less than 1, or the like so that the desired accuracy can be obtained in the analysis including GC. Use standard substances with different acid dissociation constants, such as changing the standard substance from acid to the corresponding salt, change the concentration of the standard substance in the standard solution Ss, or add an acid / base or buffer to the solution to adjust the pH. The pH of the plurality of mixed solutions M can be adjusted by adjusting the pH.

For example, it is assumed that the pH of a plurality of standard solutions Ss is measured and the difference between the pH of some standard solutions Ss and the pH of other standard solutions Ss is larger than a predetermined threshold value. In this case, the pH of the plurality of mixed solutions M can be adjusted by changing the standard substance or its concentration as described above. The threshold value is appropriately set to an arbitrary value such as 1, 2, 3, 4, or the like. When the pH of the sample solution Sn is high, the influence on the derivatization performed in the presence of the base is small. Therefore, when the pH of the sample solution Sn is high, the pH is not adjusted or the pH adjustment method is changed. Etc., the pH can be adjusted based on the pH of the sample solution Sn. By measuring the pH of the mixed solution M, it can be confirmed whether the mixed solution M that meets the conditions required by the pH has been prepared, and if necessary, re-preparation can be performed. By combining the measurement of the pH of the sample solution Sn, the standard solution Ss, and the mixed solution M, the pH can be adjusted more accurately.

(About the sample to be analyzed and the standard substance)
The sample S to be analyzed and the standard substance can be dissolved in a solvent to form a solution, and the pH of the solution can be measured, and the analysis including GC is not particularly limited as long as it is possible. The sample S to be analyzed may contain a molecule to be analyzed, and at least one of the molecules can be derivatized. When the standard substance is the internal standard Is, a molecule having a structure similar to that of the corresponding molecule to be analyzed is used, and when detected by a mass spectrometer, it is preferable to use a stable isotope of the molecule to be analyzed. When the reference substance is an external standard, in addition to the same molecules as the internal standard, the same type of molecule as the analysis target can be used as the reference substance. When methoxymation is performed and pyridine is used as the solvent for the methoxymizing agent, a cyclic molecule is included as the molecule to be analyzed.

(About derivatization)
The derivatization method is not particularly limited as long as at least a part of the derivatization reaction is carried out in the presence of a base and its efficiency depends on pH, such as oximeization such as methoxymation and TMS formation. Derivatization and combinations thereof can be used. The base is not particularly limited, but pyridine and the like can be used.

As one aspect of derivatization, methoxymization and TMS formation can be performed in the presence of pyridine. In this case, the methoxymizing agent is not particularly limited, but methoxyamine and a salt thereof can be used, and as an example, methoxyamine hydrochloride can be used. The TMS agent is not particularly limited, but for example, N-methyl-N-trimethylsilyl trifluoroacetamide (MSTFA), N-trimethylsilyl imidazole (TMSI), N, O-bis (trimethylsilyl) trifluoroacetamide (BSTFA), N, O-bis (trimethylsilyl) acetoamide (BSA), trimethylsilyldimethylamine (TMDSDMA), trimethylsilyldiethylamine (TMSDEA), trimethylchlorosilane (TMCS) and the like can be used.

(About analysis including GC)
The type of analysis of the sample Sg for GC is not particularly limited as long as GC is included, and can be performed by gas chromatography / mass spectrometry (hereinafter referred to as GC / MS) or GC using an arbitrary detector. GC / MS is performed by a gas chromatograph-mass spectrometer (hereinafter referred to as GC-MS), and GC is performed by a gas chromatograph. The method of mass spectrometry in GC / MS is not particularly limited, and one or more stages of mass spectrometry of any type or combination can be performed by a mass spectrometer combining any number and any type of mass spectrometer. it can. The detection intensity can be detected by using the peak intensity or peak area of the peak corresponding to the target molecule in the chromatogram, but the calculation method of the detection intensity is not particularly limited, for example, the peak intensity of the peak of the mass spectrum. Alternatively, the peak area or the like may be used.

(About the flow of analysis method)
FIG. 2 is a flowchart showing the flow of the analysis method according to the present embodiment. In the example of FIG. 2, the pH of the standard solution Ss containing one standard substance and the pH of the standard solution Ss containing a plurality of standard substances are measured, and the standard solution Ss is selected based on the measurement. However, the method for preparing and analyzing the sample for GC according to the present embodiment is not limited to this example, and the pH of the sample solution Sn or the mixed solution M can be measured alternative or additionally.

In step S101, the sample solution Sn is prepared. When step S101 is completed, step S103 is started. In step S103, the standard solution Ss is selected and prepared. When returning from step S107 to S103, a standard solution Ss that is at least partially different from the conventional one is selected. When step S103 is completed, step S105 is started.

In step S105, the pH of the standard solution Ss containing one standard substance and the pH of the standard solution Ss containing a plurality of standard substances are measured. When step S105 is completed, step S107 is started. In step S107, it is determined whether or not the difference between the two pH values measured in step S105 is less than the threshold value. When the difference between the two pH values is less than the threshold value, step S107 is determined affirmatively, the standard solution Ss used for preparing the GC sample Sg is determined, and step S109 is started. If the difference between the two pH values is equal to or greater than the threshold value, the negative determination in step S107 is made, and the process returns to step S103.

In step S109, derivatization is performed using the determined standard solution Ss, and a sample Sg for GC is prepared. When step S109 is completed, step S111 is started. In step S111, the GC sample Sg is subjected to analysis containing GC. When step S111 is completed, step S113 is started.

In step S113, the information obtained by the analysis including GC is output. When step S113 is completed, the process is completed.

The following modifications are also within the scope of the present invention and can be combined with the above embodiments. In the following modified examples, parts and the like exhibiting the same structure and function as those in the above-described embodiment will be referred to with the same reference numerals, and description thereof will be omitted as appropriate.
(Modification example 1)
In the above-described embodiment, derivatization is efficiently caused by measuring and adjusting the pH. However, the pH of the mixed solution may be adjusted based on the detection intensity obtained by analyzing a plurality of GC samples Sg prepared under different conditions. The method of the analysis (hereinafter referred to as trial analysis) is performed by at least GC in the same manner as the actual analysis of the sample S to be analyzed (hereinafter referred to as the main analysis), and is preferably performed by the same analysis method. As the sample solution for trial analysis (hereinafter referred to as trial sample solution), the sample solution Sn of the sample S to be analyzed may be used, or a solution containing the same type of molecule as the molecule to be analyzed may be prepared separately. Good.

In the trial analysis, the difference in the detection intensity in the data obtained by detecting the molecules contained in the trial sample solution is a plurality of GC samples for trial analysis prepared under different conditions (hereinafter referred to as trial GC samples). ), Which is less than a predetermined threshold such as 20% and 10%. In this case, it is assumed that the difference in derivatization efficiency in the preparation of these plurality of trial GC samples does not pose a problem in this analysis. Therefore, in this case, a GC sample Sg is prepared using at least a part of the standard solution Ss used for preparing the trial GC sample, for example, the most convenient one, and this analysis is performed. When the difference in detection intensity obtained by trial analysis is equal to or greater than the above-mentioned predetermined threshold value among a plurality of trial GC samples prepared under different conditions, a standard solution as in the above-described embodiment. The sample for trial GC is reprepared by reselecting Ss.

FIG. 3 is a flowchart showing the flow of the analysis method according to this modified example. In step S201, a trial sample solution is prepared. When step S201 is completed, step S203 is started. In step S203, the standard solution Ss is selected and prepared. When returning from step S211 to S203, a standard solution Ss that is at least partially different from the conventional one is selected. When step S203 is completed, step S205 is started.

In step S205, a mixed solution for trial analysis (hereinafter referred to as a trial mixed solution) is prepared. A trial mixed solution is prepared in the same manner as in the above-described embodiment except that the trial sample solution is used as the sample solution. In the example of FIG. 3, a trial mixed solution containing one standard substance and a trial mixed solution containing a plurality of standard substances are prepared. When step S205 is completed, step S207 is started. In step S207, the molecules contained in the trial mixed solution are derivatized to prepare a sample for trial GC. As the sample for trial GC, a sample for trial GC is prepared in the same manner as in the above-described embodiment except that the trial mixed solution is used as the mixed solution. When step S207 is completed, step S209 is started.

In step S209, a sample for trial GC containing one standard substance and a sample for trial GC containing a plurality of standard substances are subjected to an analysis containing at least GC (trial analysis). The detection intensity of the molecule in the data obtained by the former trial analysis is compared with the detection intensity of the molecule in the data obtained by the latter trial analysis. When step S209 is completed, step S211 is started. In step S211 it is determined whether or not the difference in the detection intensity between the plurality of trial GC samples is less than the predetermined threshold value. This determination can be performed by a gas chromatograph for performing trial analysis or a control device equipped with a CPU or the like built in or attached to or connected to an analyzer such as GC-MS. When the difference in the detection intensities is less than the predetermined threshold value, the affirmative determination is made in step S211 and step S213 is started. When the difference in the detection intensities is equal to or greater than the predetermined threshold value, the negative determination in step S211 is made, and the process returns to step S203.

In step S213, for the standard solution Ss containing a plurality of standard substances, the sample solution Sn containing the sample S to be analyzed is prepared, and the sample Sg for GC is prepared. When step S213 is completed, step S215 is started. Since steps S215 and subsequent steps are the same as steps S111 and subsequent steps in the flowchart of FIG. 2 described above, the description thereof will be omitted.

(Aspect)
It will be understood by those skilled in the art that the plurality of exemplary embodiments or modifications described above are specific examples of the following embodiments.

(Clause 1) The method for preparing a sample for gas chromatography according to one embodiment includes preparing a sample solution containing the sample, preparing a standard solution containing a standard substance having a known concentration, and using the sample solution. At least one of measurement of at least one pH of the standard solution and a mixed solution of the sample solution and the standard solution, and analysis of a solution containing the same type of molecule as the analysis target and the standard substance. To prepare a derivatization sample based on the measured pH or the data obtained by the analysis, and to contact the derivatization sample with the derivatizing agent in the presence of a base. When the analysis is performed with the preparation of a sample for gas chromatography, at least gas chromatography is performed on the solution contacted with the derivatizer in the presence of the base. This makes it possible to reduce the effect of pH on the derivatization of molecules contained in the sample.

(Item 2) In the method for preparing a sample for gas chromatography according to another aspect, when the analysis is performed in the method for preparing a sample for gas chromatography according to item 1, the method containing one kind of standard substance is contained. A comparison is made between the data obtained by the analysis of the solution and the data obtained by the analysis of the solution containing a plurality of reference substances, and the prederivative sample is prepared based on the comparison. Will be done. As a result, when performing an analysis containing GC using a plurality of different standard solutions, it is possible to confirm the effect of the plurality of standard solutions on derivatization and perform an analysis with high accuracy.

(Section 3) In the method for preparing a gas chromatography sample according to another aspect, in the method for preparing a gas chromatography sample according to the first or second paragraph, the base is pyridine. This makes it possible to perform derivatization and analysis utilizing the characteristics of pyridine.

(Item 4) In the method for preparing a gas chromatography sample according to another aspect, in the method for preparing a gas chromatography sample according to any one of items 1 to 3, the derivatizing agent is trimethylsilyl. It is an agent. As a result, various molecules can be silylated, and the target molecule can be efficiently derivatized by selecting an appropriate TMS agent.

(Clause 5) In the method for preparing a gas chromatography sample according to another aspect, in the method for preparing a gas chromatography sample according to item 3 or 4, the derivatization sample is pyridine and methoxymylated. After contacting with the methoxymization reaction solution containing the agent, contact with the trimethylsilylating agent is carried out in the presence of pyridine. In this case, the inventor has found that the pH of the derivatization sample particularly affects the efficiency of derivatization, and in such a case, the variation in derivatization due to pH can be reduced.

(Section 6) The analysis method according to one embodiment is to prepare a gas chromatography sample by the method for preparing a gas chromatography sample according to any one of paragraphs 1 to 5, and the gas chromatography sample. At least to be subjected to gas chromatography. As a result, the influence of pH on the derivatization of the molecules contained in the sample can be reduced, and the analysis can be performed with high accuracy.

The present invention is not limited to the contents of the above embodiment. Other aspects conceivable within the scope of the technical idea of the present invention are also included within the scope of the present invention.

Examples of the above-described embodiment will be shown below, but the present invention is not limited to the specific devices or conditions in the following examples.

When the pH of the standard solution used for GC / MS was measured, the standard solution of lactic acid (free form, the same applies hereinafter) was about pH 4, and some standard solutions other than lactic acid showed pH 6-7. .. When the pH of the mixed solution of 11 kinds of standard substances containing lactic acid was measured, the pH was around 4.

From the above, it was considered that the pH at the time of derivatization may differ depending on the concentration of lactic acid. The following five kinds of solutions (1) to (5) containing pyruvic acid and selectively lactic acid or sodium lactate were prepared. Sodium lactate is a weak base. The prepared solution was subjected to methoxymization and TMS formation in the presence of pyridine and then subjected to GC / MS. From the data obtained by detection by GC / MS, the area of the peak corresponding to pyruvic acid was measured as the detection intensity, and the detection intensities of the solutions (1) to (5) were compared.
(1) 500 μM pyruvic acid solution (2) 500 μM pyruvic acid 10,000 μM lactic acid solution (3) 500 μM pyruvic acid 500 μM lactic acid solution (4) 500 μM pyruvic acid 10,000 μM sodium lactate solution (5) 500 μM pyruvic acid 500 μM sodium lactate solution

Conditions for derivatization The methoxymation was carried out by drying the above solutions (1) to (5) and then adding a pyridine solution containing methoxyamine hydrochloride. TMS conversion was carried out by adding MSTFA to the reaction solution after methoxymation.

GC / MS was performed by GCMS-TQ8040 (Shimadzu), where AOC-20i (Shimadzu) was installed as an autosampler.

Conditions for gas chromatography Number and order of washings before injection: 3 times (washing twice with acetone and then washing once with pyridine)
Number and order of washings after injection: 7 times (washing 5 times with acetone and then 2 times with pyridine)
Column: BPX5 inner diameter 0.25 mm, length 30 m, film thickness 0.25 μm (SGE)
Column temperature: After holding at 60 ° C. for 2 minutes, the temperature was raised at a rate of 15 ° C./min and held at 330 ° C. for 3 minutes.
Injection temperature: 250 ° C
Carrier gas: Helium carrier gas control mode: Constant linear velocity 39.0 cm / sec Sample introduction method: Split (split ratio 30: 1)
Injection volume: 1 μL

Conditions for mass spectrometry Ionization method: Electron ionization method Ionization voltage: 70V
Ionization current: 60 μA
Interface temperature: 280 ° C
Ion source temperature: 200 ° C
Gain: Reference value (relative value of auto tuning result + 0.35 kV)
Mode: Multiple Reaction Monitoring (MRM)

FIG. 4 is a table showing the intensities of pyruvic acid and lactic acid or sodium lactate detected in GC / MS of each of the solutions (1) to (5). In the table, "Pyruvic acid-metho-TMS" indicates a methoxymated and TMS-ized pyruvate ion. "Lactic acid-2 TMS" indicates lactic acid ions that have been TMS-ized in two places. GC / MS was performed 6 times, and the result of each time was No. 1 to No. It is indicated by the number 6. The peak area of the chromatogram was used as the detection intensity. "Average", "SD" and "CV" indicate the arithmetic mean, standard deviation and coefficient of variation (%) of the detected intensities at 6 GC / MS, respectively. “Ratio” indicates the ratio (%) of the average detection intensity of pyruvic acid in each of the solutions (2) to (5) to the average detection intensity of pyruvic acid in the solution (1).

FIG. 5 is a graph showing the arithmetic mean of the peak area corresponding to pyruvic acid in the chromatogram obtained by GC / MS of the solutions (1) to (5). When lactic acid was present at a high concentration as in (2), pyruvic acid was not detected. When the concentration of lactic acid was lower than that of (2) as in (3), pyruvic acid was detected, but the detection intensity was lower than that of (1). When sodium lactate, which is a weak base, was used instead of lactic acid as in (4) and (5), the detection intensity of pyruvic acid did not decrease as compared with the case of (1).

The disclosure content of the next priority basic application is incorporated here as a quotation.
Japanese Patent Application No. 2019-079346 (filed on April 18, 2019)

M, M1, Mx ... mixed solution, S ... sample to be analyzed, Sg, Sg1, Sgx ... GC sample, Sn ... sample solution, Ss, Ss1, Ss2, Ss3 ... standard solution, Is, Is1, Is2, Is3 ... internal standard.

Claims

Preparing a sample solution containing the sample and
To prepare a standard solution containing a standard substance with a known concentration,
Measurement of at least one pH of the sample solution, the standard solution, and a mixed solution of the sample solution and the standard solution, and analysis of a solution containing the same type of molecule as the analysis target and the standard substance. To do at least one of
To prepare a derivatization sample based on the measured pH or the data obtained by the analysis.
The derivatization sample is brought into contact with a derivatizing agent in the presence of a base to prepare a gas chromatography sample.
A method for preparing a sample for gas chromatography, in which at least gas chromatography is performed on the solution contacted with the derivatizing agent in the presence of the base when the analysis is performed.
In the method for preparing a sample for gas chromatography according to claim 1.
If the analysis is performed
A comparison is made between the data obtained by the analysis of the solution containing one reference substance and the data obtained by the analysis of the solution containing a plurality of reference substances, and based on the comparison. A method for preparing a gas chromatography sample in which the derivatization sample is prepared.
In the method for preparing a sample for gas chromatography according to claim 1 or 2.
A method for preparing a sample for gas chromatography, wherein the base is pyridine.
In the method for preparing a sample for gas chromatography according to claim 1 or 2.
The method for preparing a sample for gas chromatography, wherein the derivatizing agent is a trimethylsilylating agent.
In the method for preparing a sample for gas chromatography according to claim 3.
The method for preparing a sample for gas chromatography, wherein the derivatization sample is contacted with a methoxymization reaction solution containing pyridine and a methoxymizing agent, and then contacted with a trimethylsilylating agent in the presence of pyridine.
To prepare a gas chromatography sample by the method for preparing a gas chromatography sample according to any one of claims 1 to 5.
An analytical method comprising subjecting the gas chromatography sample to at least gas chromatography.