CN111879871A - Method for predicting retention time of compound in gas chromatography analysis method - Google Patents
Method for predicting retention time of compound in gas chromatography analysis method Download PDFInfo
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- CN111879871A CN111879871A CN202010706491.7A CN202010706491A CN111879871A CN 111879871 A CN111879871 A CN 111879871A CN 202010706491 A CN202010706491 A CN 202010706491A CN 111879871 A CN111879871 A CN 111879871A
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- 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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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
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- 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
- G01N30/86—Signal analysis
- G01N30/8665—Signal analysis for calibrating the measuring apparatus
- G01N30/8668—Signal analysis for calibrating the measuring apparatus using retention times
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- 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
- G01N30/86—Signal analysis
- G01N30/8675—Evaluation, i.e. decoding of the signal into analytical information
- G01N30/8679—Target compound analysis, i.e. whereby a limited number of peaks is analysed
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Abstract
The invention belongs to the technical field of chromatographic analysis, and particularly relates to a method for predicting retention time of a compound in a gas chromatographic analysis method. The prediction method comprises the following steps: determining an initial retention time for each compound; selecting a reference system target compound; the retention time is predicted according to the prediction equation. The prediction method of the compound retention time only relates to the retention time (namely retention behaviors) of a target compound and a reference system target compound adjacent to the target compound under different chromatographic parameter conditions, and the retention behaviors of the reference system target compound and the target compound are basically consistent under different chromatographic parameter conditions due to the similarity of the molecular structures of the reference system target compound and the target compound, so that the linear insertion of the reference system target compound at nearly equal time intervals can be realized, and the retention time of the compound after the chromatographic analysis parameters are changed can be accurately predicted. Based on the same principle, the retention time of the compound after the change of gas chromatography analysis methods such as instrument replacement, instrument chromatographic column maintenance and the like can also be accurately predicted.
Description
Technical Field
The invention belongs to the field of chromatographic analysis, and particularly relates to a method for predicting retention time of a compound in a gas chromatographic analysis method.
Background
The gas chromatographic analysis is a separation and analysis method with high efficiency, high selectivity, high sensitivity, simple operation and wide application. In order to achieve the best separation effect, the optimal chromatographic analysis conditions are usually determined by repeated experiments, and the method lacks theoretical guidance and is high in workload. Especially when the number of the compounds to be tested is as high as hundreds, the determination of the optimum chromatographic conditions is very complicated and time-consuming. If the retention time of chromatographic peaks under different chromatographic analysis conditions can be predicted, and the optimal chromatographic conditions are established on the basis, the experimental times can be reduced, and the experimental time can be shortened.
Chinese patent application publication No. CN111398487A discloses a method for predicting the retention time of an object by using a retention index. The retention index is calculated as:
wherein RI is the retention index of the target compound, z is the number of carbon atoms of adjacent n-alkanes before the target compound flows out, t (x) is the measured retention time of the target compound, t (z) is the measured retention time of adjacent n-alkanes before the target compound flows out, and t (z +1) is the measured retention time of adjacent n-alkanes after the target compound flows out.
The method is suitable for the situation that the method is transferred among different instruments after the conventional maintenance of the instruments (such as replacing or cutting chromatographic columns), and due to the fact that the repeatability of the retention index of the compound is poor under the conditions of different chromatographic analysis parameters, if the chromatographic analysis parameters such as temperature programming and the like are changed, the prediction accuracy of the retention index method is remarkably reduced.
Disclosure of Invention
The invention aims to provide a method for predicting the retention time of a compound in a gas chromatographic analysis method, which is suitable for accurately predicting the retention time of the compound after chromatographic parameters are changed in the development process of the analysis method and also suitable for calibrating the retention time of the compound after the analysis method is transferred among different instruments or the instruments are subjected to conventional maintenance (replacement and cutting of chromatographic columns) under the condition that the gas chromatographic parameters are not changed.
In order to achieve the above object, the technical solution of the method for predicting retention time of a compound in a gas chromatography method of the present invention is:
a method for predicting retention time of a compound in a gas chromatography method, comprising the steps of:
1) performing gas chromatography analysis on the standard solutions of all the target compounds under the condition of initial chromatographic parameters, and determining the retention time of each target compound, and recording the retention time as the initial retention time of the compounds under the condition of the initial chromatographic parameters;
2) the initial retention time of all target compounds forms a time chain, a segmentation node is selected from the time chain to segment the time chain, and the target compounds on the segmentation node are used as reference system target compounds;
3) changing chromatographic analysis conditions, determining the retention time of a standard solution of a reference system target compound, substituting the retention time of the reference system target compound into a prediction equation, and calculating the retention time of all target compounds under the changed chromatographic analysis conditions;
changing chromatographic analysis conditions comprises changing chromatographic analysis parameters, and replacing an instrument or maintaining an instrument chromatographic column under the condition of not changing chromatographic analysis parameters;
the prediction equation is shown in formula (1):
in the formula (1), txTo change the predicted retention time of the target compound after changing the chromatographic conditions, tx1、tx2Retention times, t, of reference frame target compounds adjacent to the target compound before and after changing the chromatographic conditions, respectively0、t1、t2Initial retention times for the target compound and the reference frame target compound adjacent to the target compound before and after the target compound, respectively.
The prediction method of the compound retention time only relates to the retention time (namely retention behaviors) of a target compound and a reference system target compound adjacent to the target compound under different chromatographic parameter conditions, and the retention behaviors of the reference system target compound and the target compound are basically consistent under different chromatographic parameter conditions due to the similarity of the molecular structures of the reference system target compound and the target compound, so that the linear insertion of the reference system target compound at nearly equal time intervals can be realized, and the retention time of the compound after the chromatographic analysis parameters are changed can be accurately predicted. Based on the same principle, the retention time of the compound after the change of gas chromatography analysis methods such as instrument replacement, instrument chromatographic column maintenance and the like can also be accurately predicted.
Step 1) is to select target compounds of a reference system in a sectional mode based on the initial retention time of the compounds. The conditions of the initial chromatographic parameters are not particularly limited, and are equivalent to the initial experimental conditions, and do not require a good separation effect.
In step 2), the reference system target compound is a target compound in the analysis method or other reference substances with similar structures and similar retention time, and due to the similar molecular structures, the retention behaviors are basically consistent under different chromatographic parameter conditions.
The time chain is not required to be segmented, and the density distribution of the reference system target compounds can be carried out according to the specific analysis method. For example, depending on the different types of compounds of interest, the corresponding type of compound may be selected as the reference frame target compound. Over a certain time interval, if the number of target compounds is large, the selection amount of the target compounds in the reference system can be increased; if the number of target compounds is small, the opposite is true. It is readily understood that the greater the number of selections of reference frame target compounds, the more accurate the prediction of retention time. Preferably, in step 2), the amount of the target compound in the reference system is 5-30% of the total amount of the target compound, considering the aspects of prediction accuracy and efficiency improvement of the method. More preferably 10-20%.
In the step 3), the changing of the chromatographic analysis parameters comprises changing one or more of temperature programming, carrier gas flow rate, sample introduction mode and chromatographic column length. Under the condition that the chromatographic analysis parameters are changed, the method can still quickly and accurately predict the retention time of the compound, thereby greatly saving the development time of the analysis method.
Detailed Description
The following examples are provided to further illustrate the practice of the invention.
First, a specific example of the method for predicting the retention time of a compound in the gas chromatography analysis method of the present invention
Example 1
In this example, 207 kinds of flavor components are targeted, and the kinds include 13 kinds of aldehydes, ketones, alcohols, phenols, esters, heterocycles, ethers, hydrocarbons, sulfides, amides, anhydrides, acetals, and ketals. And (3) analyzing by adopting a gas chromatography tandem mass spectrometer, and determining the optimal chromatographic separation condition through the prediction of the retention time of all target compounds to complete the development of an analysis method.
The method for predicting the retention time of a compound in the gas chromatography analysis method of the present embodiment includes the following steps:
1) determining the initial retention time of each target Compound under initial chromatographic conditions
Initial chromatographic conditions: the chromatographic column is as follows: DB-5MS UI elastic quartz capillary chromatographic column (60m x 0.25mm x 0.25 μm). The carrier gas flow rate was 1.0 mL/min. The initial temperature programming conditions were: the initial temperature is 50 ℃, the temperature is kept for 3min, and then the temperature is increased to 290 ℃ at the speed of 5 ℃/min, and the temperature is kept for 10 min.
Standard solutions of all target compounds were assayed under initial chromatographic parameters to determine the initial retention time of each compound, as shown in table 1. In this step, the selection of the initial chromatographic conditions is not particularly critical, and is the initial fumbling experimental conditions under which the initial retention time of the compound is determined.
Table 1 compound number and initial retention time
2) Selecting a reference system target compound, and dividing a time chain
Forming a time chain according to the initial retention time of all the target compounds, selecting a segmentation node on the time chain to segment the time chain, taking the target compounds on the segmentation node as reference system target compounds, and selecting 33 reference system target compounds, which are specifically shown in table 2.
Table 2 reference frame target compound selection details
3) Determining the predicted retention time of all target compounds according to a prediction equation
Changing the temperature programming condition of the initial chromatographic condition into: the initial temperature is 50 deg.C, held for 3min, then ramped to 75 deg.C at 5 deg.C/min, held for 1min, then ramped to 150 deg.C at 1 deg.C/min, held for 1min, ramped to 260 deg.C at 2 deg.C/min, held for 1min, and finally ramped to 280 deg.C at 10 deg.C/min, held for 10 min.
Under the changed temperature programming condition, the retention time of the mixed standard solution of the 33 reference system target compounds under the changed chromatographic analysis condition is measured, and is substituted into a prediction equation to calculate the predicted retention time of all the target compounds.
Taking the bread ketone as an example, the adjacent reference system target compounds in the front and back are respectively 4-methyl-3-pentene-2-ketone and leaf aldehyde, and substituting the initial retention time and the retention time under the changed chromatographic analysis condition of the 4-methyl-3-pentene-2-ketone and the leaf aldehyde into the formula (1) to obtain the predicted retention time of the bread ketone. The predicted retention times for the remaining compounds were calculated in the same manner.
The formula (1) is:
in the formula (1), txTo change the predicted retention time of the target compound after changing the chromatographic conditions, tx1、tx2Respectively the target compounds of the reference system adjacent to the front and the back of the target compound after changing the chromatographic analysis conditionsRetention time of the substance, t0、t1、t2Initial retention times for the target compound and the reference frame target compound adjacent to the target compound before and after the target compound, respectively.
In contrast, the retention time was predicted by the retention index method (patent application CN111398487A referred to in the background section), and the difference between the predicted retention time and the actual retention time was calculated for each compound, and the results are shown in table 3.
TABLE 3 difference between predicted retention time and actual retention time for retention index method and example method
The predicted results of Table 3 were counted, and the results are shown in Table 4.
TABLE 4 comparison of prediction results for different retention time prediction methods
From the results in table 4, it can be seen that the difference between the actual retention time and the retention time in the example is mostly 0-0.1min, and the maximum time difference is within 0.3min, so that the prediction accuracy of the retention time is greatly improved compared with the retention index method, and the method is helpful for determining the optimal chromatographic analysis condition more quickly and accurately.
Example 2
This example continues the experiment on the basis of example 1.
1) Determining the initial retention time of each target Compound under initial chromatographic conditions
Initial chromatographic conditions: the initial temperature is 50 deg.C, held for 3min, then ramped to 75 deg.C at 5 deg.C/min, held for 1min, then ramped to 150 deg.C at 1 deg.C/min, held for 1min, ramped to 260 deg.C at 2 deg.C/min, held for 1min, and finally ramped to 280 deg.C at 10 deg.C/min, held for 10 min.
2) The time chain consisting of the initial retention times of 207 target compounds was divided into different time intervals, and 33 compounds on the nodes were selected as reference frame target compounds (the same as in example 1). In other embodiments, the type and amount of the reference frame target compound can be different from those in example 1.
3) Determining the predicted retention time of all target compounds according to a prediction equation
The carrier gas flow rate was changed to 1.5 mL/min.
The retention time of the 33 compound mixed standard solutions was determined under modified carrier gas flow rate conditions. The retention times of the 33 compounds were substituted into the prediction equation to calculate the retention times of the 207 target compounds.
By way of comparison, the retention times of 207 target compounds were predicted from the retention indices.
The differences between the predicted values and the actual values of the retention times of the 207 target compounds were counted, and the results are shown in table 5.
Table 5 modified carrier gas flow rate 207 compound retention time prediction results
As is clear from the results in table 5, when the subsequent chromatographic analysis conditions were changed in the flow rate of the carrier gas, the prediction accuracy of the prediction results was higher in the example method than in the retention index method.
Example 3
This example continues the experiment on the basis of example 2.
1) The predicted retention time of example 2 was taken as the initial retention time.
2) The time chain consisting of the initial retention times of 207 target compounds was divided into different time intervals, and 33 compounds on the nodes were selected as reference frame target compounds (same as in example 1).
3) The retention time of the mixed standard solution of the 33 reference system target compounds is determined on another gas chromatography tandem mass spectrometer. And substituting the retention time of the target compounds of the 33 reference systems into a prediction equation to calculate the retention time of the target compounds.
By way of comparison, the retention times of 207 target compounds were predicted from the retention indices.
The retention time deviation conditions of the 207 target compounds before and after the transfer of the analysis method among different instruments and the difference value between the predicted value and the actual value of the retention time of the 207 target compounds are counted, and the result is shown in table 6.
TABLE 6 migration of retention time of 207 compounds before and after instrumental transfer and prediction
From the results in table 6, it can be seen that the retained index method can achieve higher prediction accuracy if only the same analytical method is transferred between different instruments without changing the chromatographic parameters, and the prediction method of the present invention is also applicable to this case.
In other embodiments of the present invention, the same experimental effects as those in the above embodiments can be obtained by changing the sample injection manner, such as by changing to split, not split, or pulse sample injection, or by changing the length of the chromatographic column, based on the same working principle, and further description is omitted here.
Claims (4)
1. A method for predicting retention time of a compound in a gas chromatography method, comprising the steps of:
1) determining the retention time of each target compound by measuring the standard solution of all the target compounds under the condition of the initial chromatographic parameters, and recording the retention time as the initial retention time of the compounds under the condition of the initial chromatographic parameters;
2) the initial retention time of all target compounds forms a time chain, a segmentation node is selected from the time chain to segment the time chain, and the target compounds on the segmentation node are used as reference system target compounds;
3) changing chromatographic analysis conditions, determining the retention time of a standard solution of a reference system target compound, substituting the retention time of the reference system target compound into a prediction equation, and calculating the retention time of all target compounds under the changed chromatographic analysis conditions;
changing chromatographic analysis conditions comprises changing chromatographic analysis parameters, and replacing an instrument or maintaining an instrument chromatographic column under the condition of not changing chromatographic analysis parameters;
the prediction equation is shown in formula (1):
in the formula (1), txTo change the predicted retention time of the target compound after changing the chromatographic conditions, tx1、tx2Retention times, t, of reference frame target compounds adjacent to the target compound before and after changing the chromatographic conditions, respectively0、t1、t2Initial retention times for the target compound and the reference frame target compound adjacent to the target compound before and after the target compound, respectively.
2. The method for predicting compound retention time in a gas chromatography analysis method according to claim 1, wherein in step 2), the amount of the reference frame target compound is 5 to 30% of the total amount of the target compound.
3. The method for predicting compound retention time in a gas chromatography analysis method according to claim 2, wherein in the step 2), the number of the reference frame target compounds is 10 to 20% of the total number of the target compounds.
4. The method for predicting the retention time of a compound in a gas chromatography method according to any one of claims 1 to 3, wherein the changing of the chromatography parameter in step 3) comprises changing one or more of temperature programming, carrier gas flow rate, sample injection manner, and column length.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0637748A1 (en) * | 1993-08-02 | 1995-02-08 | Hewlett-Packard Company | Correlated multi-dimensional chromatography |
| US5827946A (en) * | 1997-04-30 | 1998-10-27 | Hewlett-Packard Company | Method for sample identification using a locked retention time database |
| US20020010566A1 (en) * | 2000-04-11 | 2002-01-24 | Chester Thomas Lee | Methods for modeling, predicting, and optimizing high performance liquid chromatography parameters |
| US20080110232A1 (en) * | 2006-11-15 | 2008-05-15 | Shimadzu Corporation | Chromatographic analyzer |
| CN111398487A (en) * | 2020-04-29 | 2020-07-10 | 中国烟草总公司郑州烟草研究院 | Application method of retention index in gas chromatography-tandem mass spectrometry analysis of tobacco flavor components |
| CN111398486A (en) * | 2020-04-29 | 2020-07-10 | 中国烟草总公司郑州烟草研究院 | Method for rapidly determining acquisition time window in gas chromatography-tandem mass spectrometry dynamic multi-reaction monitoring mode analysis method |
-
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- 2020-07-21 CN CN202010706491.7A patent/CN111879871A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0637748A1 (en) * | 1993-08-02 | 1995-02-08 | Hewlett-Packard Company | Correlated multi-dimensional chromatography |
| US5827946A (en) * | 1997-04-30 | 1998-10-27 | Hewlett-Packard Company | Method for sample identification using a locked retention time database |
| US20020010566A1 (en) * | 2000-04-11 | 2002-01-24 | Chester Thomas Lee | Methods for modeling, predicting, and optimizing high performance liquid chromatography parameters |
| US20080110232A1 (en) * | 2006-11-15 | 2008-05-15 | Shimadzu Corporation | Chromatographic analyzer |
| CN111398487A (en) * | 2020-04-29 | 2020-07-10 | 中国烟草总公司郑州烟草研究院 | Application method of retention index in gas chromatography-tandem mass spectrometry analysis of tobacco flavor components |
| CN111398486A (en) * | 2020-04-29 | 2020-07-10 | 中国烟草总公司郑州烟草研究院 | Method for rapidly determining acquisition time window in gas chromatography-tandem mass spectrometry dynamic multi-reaction monitoring mode analysis method |
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| Title |
|---|
| ALAN R.KATRITZKY等: "Prediction of Gas Chromatographic Retention Times and Response Factors Using a General Quantitative Structure-Property Relationship Treatment", 《ANAL.CHEM.》, 31 December 1994 (1994-12-31), pages 1799 - 1807 * |
| ERIC J.CAVALLI等: "Forecasting Retention Times in Temperature-Programmed Gas Chromatography: Experimental Verification of the Hypothesis on Compound Behavior", 《JOURNAL OF CHROMATOGRAPHIC SCIENCE》, vol. 34, 31 December 1996 (1996-12-31), pages 547 - 549 * |
| 张婕等: "用数字模拟方法预测毛细管气相色谱保留时间", 《分析仪器》, no. 01, 28 January 2011 (2011-01-28), pages 51 - 58 * |
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