A qualitative and quantitative detection method and detection equipment for liquid materials

Abstract

The present invention belongs to the technical field of analysis and detection, and specifically relates to a qualitative and quantitative detection method and detection equipment for liquid materials. The method has the following advantages: 1) This detection method realizes quantitative detection of all samples through one needle. 2) This detection method can realize accurate quantitative detection for any component with a content between 0-100%, for example, high-content components (50-99%) can be accurately quantitatively detected, and trace components (0.01-1%) can also be accurately quantitatively detected. 3) This detection method, by adopting different types of chromatographic columns and injecting samples at one time, can not only realize the separation and qualitative and quantitative detection of similar substances, but also realize the separation and qualitative and quantitative detection of different types of substances.

Description

Technical Field

[0001] The invention belongs to the technical field of analysis and detection, and in particular relates to a qualitative and quantitative detection method and detection equipment for liquid materials. Background Art

[0002] In the chemical industry, in order to control the reaction process, it is often necessary to monitor the reaction system at different reaction stages in real time, and understand the reaction process and reaction conditions through real-time qualitative and quantitative detection of each component in the reaction system, so as to achieve reaction optimization and improve reaction efficiency and yield. Taking the oxidation of isobutane to prepare tert-butyl alcohol and tert-butyl hydroperoxide as an example, the reaction product contains the prepared tert-butyl alcohol and tert-butyl hydroperoxide, the by-product di-tert-butyl peroxide, unreacted isobutane and oxidant, and other impurities. The system to be detected is extremely complex, including both liquid materials and gas materials. How to conduct qualitative and quantitative detection of each component, especially the real-time qualitative and quantitative detection of liquid materials, is one of the key points and difficulties of analytical detection.

[0003] The reason why the detection of the liquid material is difficult is that the component composition and content contained in each real-time sampled liquid material to be tested are extremely complex. For example, the content of some components is extremely high, which can reach more than 99%. How to achieve quantitative detection of trace components becomes a problem; the residence time of some components is particularly long, so how to achieve efficient detection of different components becomes a problem; in addition, it is necessary to match different detectors according to different component compositions, such as FID (hydrogen flame ionization detector), TCD (thermal conductivity cell detector), etc. Therefore, the method of the prior art needs to use two or three needles for detection, and the detection efficiency is very low. Summary of the invention

[0004] In order to improve the deficiencies of the prior art, the purpose of the present invention is to provide a qualitative and quantitative detection method and detection equipment for liquid materials. Based on the method and equipment, qualitative and quantitative analysis of components with large differences in content or properties in liquid materials can be completed in one injection, with high detection efficiency and high detection accuracy, which is very conducive to promotion and application.

[0005] The object of the present invention is achieved through the following technical solutions:

[0006] A qualitative and quantitative detection device for liquid materials, the device comprising a gas chromatograph, a first detector and a second detector;

[0007] The gas chromatograph comprises an injection port, a first chromatographic column, a second chromatographic column and a central cutting component;

[0008] One end of the first chromatographic column is connected to the inlet of the gas chromatograph, and the other end is connected to the inlet end of the center cutting component, the first outlet end of the center cutting component is connected to the first detector; the second outlet end is connected to the second chromatographic column, and the outlet end of the second chromatographic column is connected to the second detector;

[0009] The first detector and the second detector are thermal conductivity detectors or hydrogen flame ionization detectors.

[0010] According to the present invention, the device further comprises a third chromatographic column, and the first outlet end of the central cutting component is connected to the first detector via the third chromatographic column.

[0011] According to the present invention, the third chromatographic column can be an unfilled capillary column or a filled capillary column.

[0012] According to the present invention, the device also includes an automatic flow controller and an automatic pressure controller, wherein the automatic flow controller is connected to the injection port to control the carrier gas flow, and the automatic pressure controller is connected to the center cutting component to control the cutting direction of the center cutting component.

[0013] The present invention also provides a method for qualitative and quantitative detection of liquid materials, the method is based on the above detection device, and the method comprises the following steps:

[0014] Injecting a liquid material to be tested into the injection port of a gas chromatograph, the liquid material contains different components, the liquid material is vaporized at the injection port, and flows through a first chromatographic column for preliminary separation of the components, and the components with large residence time differences are respectively sent to a first detector and a second detector for detection by using a center cutting component and a center cutting technique;

[0015] At the same time, the components are separated again by a second chromatographic column before being detected by the second detector.

[0016] According to the present invention, the heart-cutting technology is a valve switching action, which sends components with different residence times into different gas paths to be detected by specific detectors, thereby achieving the separation of components with large differences in physical and chemical properties and contents.

[0017] According to the present invention, the first chromatographic column is selected from a medium-polarity chromatographic column, such as a 17 chromatographic column, a 1701 chromatographic column, a 1301 chromatographic column or a 624 chromatographic column; the second chromatographic column is selected from a polar chromatographic column, such as a WAX chromatographic column, a FFAP chromatographic column or a BP-21 chromatographic column.

[0018] According to the present invention, the liquid material to be tested may be, for example, an isobutane oxidation system, an isobutylene catalytic oxidation system, a propylene catalytic oxidation system, etc. Exemplarily, the liquid material includes at least one of tert-butyl alcohol (TBA), tert-butyl formate (TBF), tert-butyl hydroperoxide (TBHP), methyl formate, acetone, methanol, isopropanol, di-tert-butyl hydroperoxide (DTBP), isobutyl formate (IBF), isobutanol, acetic acid, isobutyric acid, etc.

[0019] According to the present invention, the method comprises the following steps:

[0020] 1) The liquid material is vaporized at the injection port and flows through the first chromatographic column for preliminary separation of components to obtain several components with different residence times;

[0021] 2) The heart cutting component uses the heart cutting technology to separate and detect several components. The specific steps are as follows:

[0022] 2-1) When the heart cutting starts in a solid line state, the first chromatographic column and the second chromatographic column are connected in parallel, and the first chromatographic column and the third chromatographic column are connected in series; at this time, all components enter the first chromatographic column for pre-separation;

[0023] 2-2) Using the event Relay (110), the heart cut is switched to a dotted line state; at this time, the first chromatographic column is connected in series with the second chromatographic column, and the first chromatographic column is connected in parallel with the third chromatographic column; at this time, a component flows out of the first chromatographic column, is separated by the second chromatographic column, and is detected by the second detector; the remaining components remain in the first chromatographic column;

[0024] 2-3) using the event Relay (-110) to switch the heart cut to a solid line state; when the heart cut is in a solid line state again, the first chromatographic column and the second chromatographic column are connected in parallel, and the first chromatographic column and the third chromatographic column are connected in series; at this time, one of the remaining components in step 2-2) passes through the first chromatographic column into the third chromatographic column and is detected by the first detector, and the remaining components remain in the first chromatographic column;

[0025] 2-4) using the event Relay (110) to switch the heart cut to a dotted state; when the heart cut is in the dotted state again, the first chromatographic column is connected in series with the second chromatographic column, and the first chromatographic column is connected in parallel with the third chromatographic column; at this time, one of the remaining components in step 2-3) passes through the second chromatographic column and is detected by the second detector; the remaining components remain in the first chromatographic column;

[0026] 2-5) Repeat the above steps 2-3) and 2-4) until the end of the experiment.

[0027] According to the present invention, the method comprises the following steps:

[0028] 1') the liquid material is vaporized at the injection port and flows through the first chromatographic column for preliminary separation of components to obtain four groups of components, namely a first component, a second component, a third component and a fourth component, wherein the first component contains at least one component of methyl formate, methanol, acetone and isopropanol, the second component contains at least one component of TBA+TBF, the third component contains at least one component of DTBP+IBF+isobutanol+acetic acid, and the fourth component contains at least one component of TBHP+isobutyric acid;

[0029] 2') The above four groups of components are separated and tested by using the heart cutting technology through the heart cutting component. The specific steps are as follows:

[0030] 2-1') When the heart cutting starts in a solid line state, the first chromatographic column and the second chromatographic column are connected in parallel, and the first chromatographic column and the third chromatographic column are connected in series; at this time, all components enter the first chromatographic column for pre-separation;

[0031] 2-2') Use event Relay (110) to switch the heart cutting to a dotted line state; at this time, the first chromatographic column and the second chromatographic column are connected in series, and the first chromatographic column and the third chromatographic column are connected in parallel; at this time, the first component flows out of the first chromatographic column, is separated by the second chromatographic column, and is detected by the second detector; the second component, the third component and the fourth component remain in the first chromatographic column;

[0032] 2-3') Use event Relay (-110) to switch the heart cutting to a solid line state; when the heart cutting is in a solid line state again, the first chromatographic column and the second chromatographic column are connected in parallel, and the first chromatographic column and the third chromatographic column are connected in series; at this time, the second component enters the third chromatographic column through the first chromatographic column and is detected by the first detector, and the third component and the fourth component remain in the first chromatographic column;

[0033] 2-4') using the event Relay (110) to switch the heart cut to a dotted state; when the heart cut is in the dotted state again, the first chromatographic column is connected in series with the second chromatographic column, and the first chromatographic column is connected in parallel with the third chromatographic column; at this time, the third component passes through the second chromatographic column and is detected by the second detector; the fourth component still remains in the first chromatographic column;

[0034] 2-5') Use event Relay (-110) to switch the heart cut to a solid line state; when the heart cut is in a solid line state again, the first chromatographic column and the second chromatographic column are connected in parallel, and the first chromatographic column and the third chromatographic column are connected in series; at this time, the fourth component enters the third chromatographic column through the first chromatographic column and is detected by the first detector, and the experiment ends.

[0035] Beneficial effects of the present invention:

[0036] 1) This detection method achieves quantitative detection of all samples through one needle.

[0037] 2) This detection method can achieve accurate quantitative detection for any component with a content between 0-100%. For example, high-content components (50-99%) can be accurately quantitatively detected, and trace components (0.01-1%) can also be accurately quantitatively detected.

[0038] 3) This detection method, by using different types of chromatographic columns, can not only achieve the separation and qualitative and quantitative detection of the same type of substances, but also the separation and qualitative and quantitative detection of different types of substances in one injection. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic diagram of the structure of the detection equipment of the present invention.

[0040] Figure 2 This is a schematic diagram of the FID1 detection results shown in Example 2 of the present invention.

[0041] Figure 3 This is a schematic diagram of the FID2 detection results shown in Example 2 of the present invention. DETAILED DESCRIPTION

[0042] The method of the present invention will be described in further detail below in conjunction with specific examples. It should be understood that the following examples are only exemplary descriptions and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are included in the scope that the present invention is intended to protect.

[0043] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods; the reagents, materials, etc. used in the following examples, unless otherwise specified, can be obtained from commercial channels.

[0044] In the description of the present invention, it should be noted that the terms "first", "second", etc. are only used for descriptive purposes, and do not indicate or imply relative importance.

[0045] Example 1

[0046] The present embodiment provides a qualitative and quantitative detection device for liquid materials, the device comprising a gas chromatograph, a third chromatographic column, a first detector, a second detector, an automatic flow controller and an automatic pressure controller; the gas chromatograph comprises an injection port, a first chromatographic column, a second chromatographic column and a center cutting component; one end of the first chromatographic column is connected to the injection port of the gas chromatograph, and the other end is connected to the inlet end of the center cutting component, the first outlet end of the center cutting component is connected to the first detector through the third chromatographic column; the second outlet end is connected to the second chromatographic column, and the outlet end of the second chromatographic column is connected to the second detector;

[0047] The first detector and the second detector are thermal conductivity detectors or hydrogen flame ionization detectors; the automatic flow controller is connected to the injection port to control the carrier gas flow; the automatic pressure controller is connected to the center cutting component to control the cutting direction of the center cutting component.

[0048] Example 2

[0049] The liquid material to be tested is injected into the injection port of the gas chromatograph described in Example 1. The parameters of the gas chromatograph are as follows:

[0050] The first chromatographic column: capillary column (1701); the second chromatographic column: capillary column (WAX);

[0051] Column box: initial temperature 50℃, maintained for 6min, heated to 110℃ at 12℃ / min, then heated to 220℃ at 25℃ / min and maintained for 5min; carrier gas: nitrogen; first detector (FID1) and second detector (FID2) temperature 230℃; injection port SPL temperature: 150℃; split ratio: 150:1; purge flow rate 3.0mL / min:

[0052] Time program:

[0053] Table 1 Time program

[0054] time equipment event Settings 2.90 advanced event 110 3.65 advanced event -110 4.65 advanced event 110 7.00 advanced event -110

[0055] The components contained in the liquid material are shown in Table 2 below:

[0056] Table 2 Components contained in liquid materials

[0057]

[0058] like Figure 1 As shown, the liquid material is vaporized at the injection port and flows through the first chromatographic column for preliminary separation of the components. The components with large residence time differences are respectively sent to the first detector FID1 and the second detector FID2 for detection using the center cutting technology through the center cutting component; at the same time, the components are separated again by the second chromatographic column before being detected by the second detector FID2.

[0059] The specific operation process is as follows: the gas sample in the quantitative loop enters the split injection port, and the split sample enters the analysis system. After separation by the 1701 chromatographic column, the components are divided into four groups:

[0060] The first component contains at least one of methyl formate, methanol, acetone and isopropanol, the second component contains at least one of TBA+TBF, the third component contains at least one of DTBP+IBF+isobutanol+acetic acid, and the fourth component contains at least one of TBHP+isobutyric acid.

[0061] 1. When the heart cutting starts in a solid line state, the first chromatographic column and the second chromatographic column are connected in parallel, and the first chromatographic column and the third chromatographic column are connected in series; at this time, all components enter the first chromatographic column for pre-separation;

[0062] 2. Use the event Relay (110) to switch the heart cutting to a dotted line state; at this time, the first chromatographic column is connected in series with the second chromatographic column, and the first chromatographic column is connected in parallel with the third chromatographic column; at this time, the first component flows out of the first chromatographic column, is separated by the second chromatographic column, and is detected by the second detector; the second component, the third component, and the fourth component remain in the first chromatographic column;

[0063] 3. Use the event Relay (-110) to switch the heart cutting to a solid line state; when the heart cutting is in a solid line state again, the first chromatographic column and the second chromatographic column are connected in parallel, and the first chromatographic column and the third chromatographic column are connected in series; at this time, the second component enters the third chromatographic column through the first chromatographic column and is detected by the first detector, and the third component and the fourth component remain in the first chromatographic column;

[0064] 4. Use the event Relay (110) to switch the heart cut to a dotted state; when the heart cut is in the dotted state again, the first chromatographic column is connected in series with the second chromatographic column, and the first chromatographic column is connected in parallel with the third chromatographic column; at this time, the third component passes through the second chromatographic column and is detected by the second detector; the fourth component still remains in the first chromatographic column;

[0065] 5. Use the event Relay (-110) to switch the heart cut to a solid line state; when the heart cut is in a solid line state again, the first chromatographic column and the second chromatographic column are connected in parallel, and the first chromatographic column and the third chromatographic column are connected in series; at this time, the fourth component enters the third chromatographic column through the first chromatographic column and is detected by the first detector, and the experiment ends.

[0066] The components detected by the two detectors FID1 and FID2 are shown in Tables 3 and 4, and Figure 2 and Figure 3 shown.

[0067] Table 3 FID1 detection peak table

[0068] Peak Compound Name Retention time area area% Resolution (USP) 1 TBA 3.568 2818800 53.419 -- 2 TBF 4.313 83688 1.586 11.676 3 TBHP 7.789 2198746 41.668 37.961 4 Isobutyric acid 9.796 169548 3.213 14.56

[0069] Table 4 FID2 detection peak table

[0070] Peak Compound Name Retention time area area% Resolution (USP) 1 Methyl formate 4.981 33654 3.424 -- 2 acetone 5.759 127600 12.983 11.346 3 Methanol 6.263 88964 9.052 6.828 4 Isopropyl alcohol 6.897 120198 12.23 8.021 5 DTBP 7.214 169890 17.286 3.763 6 IBF 8.527 98390 10.011 16.745 7 Isobutanol 9.549 205760 20.936 13.905 8 Acetic acid 13.457 77039 7.839 57.498

[0071] After the above analysis and testing, the content of each component in the sample to be tested is calculated as follows:

[0072] Serial number Sample name Content wt% 1 TBA 16.34 2 TBHP 28.43 3 acetone 1.12 4 Methanol 0.16 5 Unknown 0.47 6 DTBP 0.57 7 Methyl formate 0.02 8 Acetic acid 0.16 9 Isobutyric acid 0.32 10 Isobutanol 0.22 11 wUnknown thing 0.66 12 Isopropyl alcohol 0.05 13 TBF 0.01 14 IBF 0.02

[0073] The above is an explanation of the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for qualitative and quantitative detection of liquid materials, wherein: The detection equipment used in the detection method includes a gas chromatograph, a first detector and a second detector; The gas chromatograph comprises an injection port, a first chromatographic column, a second chromatographic column and a central cutting component; One end of the first chromatographic column is connected to the inlet of the gas chromatograph, and the other end is connected to the inlet end of the center cutting component, and the first outlet end of the center cutting component is connected to the first detector; The second outlet end is connected to a second chromatographic column, and the outlet end of the second chromatographic column is connected to a second detector; The first detector and the second detector are thermal conductivity cell detectors or hydrogen flame ionization detectors; The device further comprises a third chromatographic column, and the first outlet end of the center-cutting component is connected to the first detector via the third chromatographic column; The method comprises the following steps: 1) injecting a liquid material to be tested into an injection port of a gas chromatograph, vaporizing the liquid material at the injection port, and flowing through a first chromatographic column for preliminary separation of components to obtain a plurality of components with different residence times; the liquid material to be tested is an isobutane oxidation system, an isobutylene oxidation system or a propylene oxidation system; 2) The heart cutting component uses the heart cutting technology to separate and detect several components. The specific steps are as follows: 2-1) When the heart cutting starts in a solid line state, the first chromatographic column and the second chromatographic column are connected in parallel, and the first chromatographic column and the third chromatographic column are connected in series; at this time, all components enter the first chromatographic column for pre-separation; 2-2) Using the event Relay (110), the heart cut is switched to a dotted line state; at this time, the first chromatographic column is connected in series with the second chromatographic column, and the first chromatographic column is connected in parallel with the third chromatographic column; at this time, a component flows out of the first chromatographic column, is separated by the second chromatographic column, and is detected by the second detector; the remaining components remain in the first chromatographic column; 2-3) using the event Relay (-110) to switch the heart cut to a solid line state; when the heart cut is in a solid line state again, the first chromatographic column and the second chromatographic column are connected in parallel, and the first chromatographic column and the third chromatographic column are connected in series; At this time, one of the remaining components in step 2-2) enters the third chromatographic column through the first chromatographic column and is detected by the first detector, and the remaining components remain in the first chromatographic column; 2-4) using the event Relay (110) to switch the heart cut to a dotted state; when the heart cut is in the dotted state again, the first chromatographic column is connected in series with the second chromatographic column, and the first chromatographic column is connected in parallel with the third chromatographic column; at this time, one of the remaining components in step 2-3) passes through the second chromatographic column and is detected by the second detector; the remaining components remain in the first chromatographic column; 2-5) Repeat the above steps 2-3) and 2-4) until the end of the experiment; The first chromatographic column is selected from a medium-polarity chromatographic column; the second chromatographic column is selected from a polarity chromatographic column.

2. The detection method according to claim 1, wherein: The device also includes an automatic flow controller and an automatic pressure controller. The automatic flow controller is connected to the injection port to control the flow of the carrier gas, and the automatic pressure controller is connected to the center cutting component to control the cutting direction of the center cutting component.

3. The detection method according to claim 1, wherein: The first chromatographic column is a 17 chromatographic column, a 1701 chromatographic column, a 1301 chromatographic column or a 624 chromatographic column.

4. The detection method according to claim 1, wherein: The second chromatographic column is a WAX chromatographic column, a FFAP chromatographic column or a BP-21 chromatographic column.

5. The detection method according to claim 1, wherein the liquid material comprises at least one of tert-butyl alcohol (TBA), tert-butyl formate (TBF), tert-butyl hydroperoxide (TBHP), methyl formate, acetone, methanol, isopropanol, di-tert-butyl hydroperoxide (DTBP), isobutyl formate (IBF), isobutanol, acetic acid, and isobutyric acid.

6. The detection method according to claim 5, wherein: The method comprises the following steps: 1') the liquid material is vaporized at the injection port and flows through the first chromatographic column for preliminary separation of components to obtain four groups of components, namely a first component, a second component, a third component and a fourth component, wherein the first component contains at least one component of methyl formate, methanol, acetone and isopropanol, the second component contains at least one component of TBA+TBF, the third component contains at least one component of DTBP+IBF+isobutanol+acetic acid, and the fourth component contains at least one component of TBHP+isobutyric acid; 2') The above four groups of components are separated and tested by using the heart cutting technology through the heart cutting component. The specific steps are as follows: 2-1') When the heart cutting starts in a solid line state, the first chromatographic column and the second chromatographic column are connected in parallel, and the first chromatographic column and the third chromatographic column are connected in series; at this time, all components enter the first chromatographic column for pre-separation; 2-2') Use event Relay (110) to switch the heart cutting to a dotted line state; at this time, the first chromatographic column and the second chromatographic column are connected in series, and the first chromatographic column and the third chromatographic column are connected in parallel; at this time, the first component flows out of the first chromatographic column, is separated by the second chromatographic column, and is detected by the second detector; the second component, the third component and the fourth component remain in the first chromatographic column; 2-3') Use event Relay (-110) to switch the heart cutting to a solid line state; when the heart cutting is in a solid line state again, the first chromatographic column and the second chromatographic column are connected in parallel, and the first chromatographic column and the third chromatographic column are connected in series; at this time, the second component enters the third chromatographic column through the first chromatographic column and is detected by the first detector, and the third component and the fourth component remain in the first chromatographic column; 2-4') using the event Relay (110) to switch the heart cut to a dotted state; when the heart cut is in the dotted state again, the first chromatographic column is connected in series with the second chromatographic column, and the first chromatographic column is connected in parallel with the third chromatographic column; at this time, the third component passes through the second chromatographic column and is detected by the second detector; the fourth component still remains in the first chromatographic column; 2-5') Use event Relay (-110) to switch the heart cut to a solid line state; when the heart cut is in a solid line state again, the first chromatographic column and the second chromatographic column are connected in parallel, and the first chromatographic column and the third chromatographic column are connected in series; at this time, the fourth component enters the third chromatographic column through the first chromatographic column and is detected by the first detector, and the experiment ends.

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