Method for researching polyolefin resin odor compound based on headspace-gas chromatography-ion mobility spectrometry technology

Abstract

The invention discloses a method for researching a polyolefin resin odor compound based on a headspace-gas chromatography-ion mobility spectrometry technology. The method is specifically implemented according to the following steps: step 1, carrying out headspace-gas chromatography-ion mobility spectrometry detection on polyolefin resin; step 2, extracting signal peaks of volatile compounds of different brands of resin through software LAV to construct a fingerprint spectrum; step 3, carrying out qualitative analysis processing on the signal peak of the area selected in the step 2 through GC-IMS Library Search Software qualitative software, and carrying out qualitative analysis processing on the signal peak of the area selected in the step 2 through GC-IMS Library Search Software qualitative software; step 4, taking the signal intensity of each compound in the odor compound fingerprint as a basis for comparing odor substances of resins with different brands, the GC-IMS technology is applied to odor analysis of related materials such as polyolefin resins with various brands, sample pretreatment is simple, complex pretreatment is not needed, the detection period is short, and the detection accuracy is high. Compared with the prior art, the method has the advantages of high sensitivity, resolution and resolution, and can compare and analyze the difference of odor compounds of different samples through the obtained fingerprint spectrum, carry out visual monitoring, and reduce the difficulty of difference analysis of different samples.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical detection, and particularly relates to a method for studying polyolefin resin odor compounds based on headspace-gas chromatography-ion mobility spectrometry technology. Background Art

[0002] Polyolefin resins possess excellent physical properties and processability. Through processing, they are used to produce products such as plastic films, plastic containers, and plastic fibers, which are widely used in packaging, food, pharmaceuticals, automobiles, and construction. As the polyolefin resin industry develops, demand for new, low-odor, clean polyolefin resins is also growing. Accurately identifying odorous substances in materials can provide data support for the development of clean polyolefin resins.

[0003] In recent years, the automotive industry has used artificial olfaction to evaluate the odor levels of polyolefin materials, with the reference standard being PV3900. This method can initially distinguish the odor levels of materials, but it cannot accurately perform a qualitative analysis of odor compounds, nor can it determine the specific compounds causing the odor. Furthermore, the odor level graduation values ​​are large, and the odor detection is too general. For example, one study found that the burnt odor produced by automotive polypropylene composite materials is the result of the combined effects of alkanes and aldehydes and ketones on the sense of smell, and it is impossible to determine the specific compounds causing the odor. The researchers used solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS) to determine the volatile components of two polyolefin resins. 58 species were detected in the resin used to produce plastic bags, and 66 species were detected in the resin used to produce plastic bottles, mainly including alkanes, benzene rings, alcohols, esters, ethers and other compounds. Although HS-SPME-GC-MS technology can qualitatively identify odor compounds in polyolefin resin products and detect odor compounds in samples, the detection process of this method is cumbersome. Not only is the sample detection time long, but it also requires a lot of time for data processing.

[0004] The complex composition of volatile compounds in polyolefin resins makes comparative analysis of odor components between samples a cumbersome process. Gas chromatography-ion mobility spectrometry (GC-IMS) combines gas chromatography with ion mobility spectrometry. After initial separation by GC, the sample enters the IMS, where it is further analyzed under the influence of an electric field. GC-IMS detects the sample without requiring sample pretreatment, such as enrichment. Volatile components in the sample undergo multiple separations by GC and IMS, achieving multidimensional separation of the volatile components with high resolution and resolution. Compared to volatile component detection techniques such as GC-MS and GC-O, GC-IMS requires simple sample pretreatment and offers higher sensitivity, resolution, and resolution. Its data processing software, LAV, enables visual comparison of odor compounds in different samples, significantly reducing the time, effort, and effort required to analyze differences between samples. Currently, GC-IMS has not been well-approved for detecting odor compounds in polymer materials such as polyolefin resins and polyolefin resin additives. Applying GC-IMS technology to the odor analysis of polyolefin resins and other related materials not only simplifies sample pretreatment, shortens the detection cycle, and achieves high sensitivity, separation, and resolution, but also enables comparative analysis of the differences in odor compounds among different samples through the acquired fingerprints, allowing for visual monitoring. This provides a new method for the rapid detection and comparative analysis of odor compounds in a variety of polyolefin resins and other materials. Summary of the Invention

[0005] The present invention aims to provide a method for analyzing odorous compounds in polyolefin resins based on headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS). This method qualitatively characterizes volatile odorous compounds in different grades of polyolefin resins and rapidly analyzes and compares the differences in volatile odorous compounds in different types of additives, enabling visual monitoring of odorous compounds. The developed method features simple pretreatment, a short detection cycle, high sensitivity, separation, and resolution, and allows for visual monitoring.

[0006] The technical solution adopted by the present invention is a method for studying odor compounds in polyolefin resins based on headspace-gas chromatography-ion mobility spectrometry technology, which is specifically implemented according to the following steps:

[0007] Step 1: The polyolefin resin is subjected to headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS) detection;

[0008] Step 2: Use the software LAV to extract the signal peaks of volatile compounds of different brands of resins and construct fingerprints;

[0009] Step 3: Perform qualitative analysis on the signal peaks in the area selected in step (2) using the GC-IMS Library Search Software qualitative software;

[0010] Step 4: The signal intensity of each compound in the odor compound fingerprint is used as the basis for comparing the odor substances of different brands of resins.

[0011] The present invention is also characterized in that:

[0012] The operation of headspace sampling in the headspace-gas chromatography-ion mobility spectrometry detection in step 1 is as follows: weigh 2 g of polyolefin resin sample into a headspace bottle, incubate at 60°C and 500 rpm for 30 minutes, take 500 μL of headspace gas, and perform automatic headspace sampling.

[0013] The ion mobility spectrometry detection conditions for headspace gas chromatography-ion mobility spectrometry in step 1 were: an inlet temperature of 85°C. The carrier gas was high-purity nitrogen with a purity of ≥99.999%, and the flow rate program was as follows: 2 mL / min for 2 minutes, 20 mL / min for 8 minutes, 100 mL / min for 10 minutes, and 150 mL / min for 40 minutes, for a total run time of 60 minutes.

[0014] The gas chromatography detection conditions in the headspace-gas chromatography-ion mobility spectrometry detection in step 1 are: chromatographic column FS-SE-54-CB-1 capillary column (column length 15m, inner diameter 0.53mm, film thickness 1μm ) , the column temperature was 40 °C, the operating temperature of the ion migration tube was 45 °C, the nitrogen flow rate was 150 mL / min, the data acquisition was in positive ion mode, and orthoketone C4 to C9 were used as external standard references.

[0015] In step 2, the resin HS-GC-IMS test results are analyzed in the LAV software, and the signal peaks of volatile compounds in the sample are selected to construct the fingerprint spectrum of the polyolefin resin odor compounds.

[0016] In step 3, the volatile compound signal peaks extracted in step 1 are qualitatively analyzed using the built-in NIST14 database of GC-IMS Library Search Software to obtain qualitative analysis results of the volatile compound signal peaks.

[0017] In step 4, the qualitative analysis results based on the signal peaks of volatile compounds are combined with the constructed fingerprint to achieve a visual analysis of the differences in odor compounds between samples.

[0018] The intensity of each signal peak in the fingerprint spectrum in step 4 is expressed as follows: the intensity of the odor substance with the highest content in the resin odor compound is set to 100, and the intensity of other compounds is the ratio to 100.

[0019] The present invention has the following beneficial effects: It applies GC-IMS technology to the odor analysis of various grades of polyolefin resins and other related materials. This method not only simplifies sample pretreatment, eliminating the need for complex pretreatment, shortens the detection cycle, and achieves high sensitivity, resolution, and resolution. Furthermore, the acquired fingerprints enable comparative analysis of odor compounds in different samples, enabling visual monitoring and reducing the difficulty of differential analysis. This provides a new method for the rapid detection and comparative analysis of odor compounds in various grades of polyolefin resins. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a gallery plot of volatile organic compounds in three different grades of polyolefin resins according to Example 1 of the method for studying odor compounds in polyolefin resins based on headspace-gas chromatography-ion mobility spectrometry technology of the present invention. DETAILED DESCRIPTION

[0021] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] The present invention is based on the method of studying polyolefin resin odor compounds using headspace-gas chromatography-ion mobility spectrometry technology, which is specifically implemented according to the following steps:

[0023] Step 1: subjecting the polyolefin resin to headspace-gas chromatography ion mobility spectrometry detection;

[0024] The headspace sampling operation in the headspace-gas chromatography-ion mobility spectrometry detection in step 1 is as follows: 2 g of polyolefin resin sample is weighed into a headspace vial, incubated at 60°C and 500 rpm for 30 min, 500 μL of headspace gas is collected, and automatic headspace sampling is performed;

[0025] The ion mobility spectrometry detection conditions in the headspace-gas chromatography-ion mobility spectrometry detection in step 1 are as follows: the inlet temperature is 85°C. The carrier gas is high-purity nitrogen with a purity of ≥99.999%, and the flow rate program is as follows: 2 mL / min for 2 minutes, 20 mL / min for 8 minutes, 100 mL / min for 10 minutes, and 150 mL / min for 40 minutes, with a total run time of 60 minutes.

[0026] The gas chromatography detection conditions in the headspace-gas chromatography-ion mobility spectrometry detection in step 1 are as follows: a chromatographic column FS-SE-54-CB-1 capillary column with a column length of 15 m, an inner diameter of 0.53 mm, and a film thickness of 1 μm; a column temperature of 40° C., an operating temperature of the ion migration tube of 45° C., a nitrogen flow rate of 150 mL / min, data acquisition in positive ion mode, and orthoketones C4 to C9 as external standards;

[0027] Step 2: Use the software LAV to extract the signal peaks of volatile compounds of different brands of resins and construct fingerprints;

[0028] In step 2, the resin HS-GC-IMS test results are analyzed in LAV software, and the signal peaks of volatile compounds in the sample are selected to construct a fingerprint spectrum of polyolefin resin odor compounds;

[0029] Step 3: Perform qualitative analysis on the signal peaks in the area selected in step (2) using the GC-IMS Library Search Software qualitative software;

[0030] In step 3, the GC-IMS Library Search Software was used to perform qualitative analysis of the substances based on DT (drift time), RI (retention index), and RT (retention time) in the NIST14 database. After removing dimers and polymers, the GC-IMS qualitative results were obtained by classifying the compounds according to their types.

[0031] Step 4: The signal intensity of each compound in the odor compound fingerprint is used as the basis for comparing the odor substances of different brands of resins.

[0032] In step 4, the qualitative analysis results based on the volatile compound signal peaks are combined with the constructed fingerprint to achieve a visual analysis of the differences in odor compounds between samples;

[0033] The intensity of each signal peak in the fingerprint spectrum in step 4 is expressed as follows: the intensity of the odorous substance with the highest content in the resin odor compound is set as 100, and the intensity of other compounds is the ratio to 100.

[0034] Example 1

[0035] Step 1: HS-GC-IMS analysis

[0036] 2 g of polyolefin resins of different brands were respectively taken for headspace-gas chromatography-ion mobility spectrometry analysis.

[0037] Headspace conditions: Weigh 2 g of polyolefin resin sample into a headspace vial, incubate at 60°C, 500 rpm for 30 min, take 500 μL of headspace gas, and perform automatic headspace sampling.

[0038] Ion mobility spectrometry detection conditions: the inlet temperature was 85°C. The carrier gas was high-purity nitrogen with a purity of ≥99.999%. The flow rate program was as follows: 2 mL / min for 2 min, 20 mL / min for 8 min, 100 mL / min for 10 min, and 150 mL / min for 40 min, with a total run time of 60 min.

[0039] The chromatographic column was a FS-SE-54-CB-1 capillary column with a length of 15 m, an inner diameter of 0.53 mm, a film thickness of 1 μm, a column temperature of 40 °C, an operating temperature of the ion migration tube of 45 °C, and a nitrogen flow rate of 150 mL / min.

[0040] Data were collected in positive ion mode, using C4-C9 ketones as external standards.

[0041] Step 2: HS-GC-IMS detection obtains the volatile compound data in the sample, and the signal peaks of the volatile compounds of each brand of resin are extracted using LAV software, and a fingerprint of the volatile compounds of the polyolefin resin is constructed.

[0042] Step 3: Perform qualitative analysis on the signal peaks extracted by LAV in step 2 using GC-IMS Library Search Software. Qualitative analysis of the substances is performed based on DT (drift time), RI (retention index), and RT (retention time) in the NIST14 database. After removing dimers and polymers, the GC-IMS qualitative results are obtained by classifying the compounds according to their types.

[0043] Step 4: Based on the fingerprint of volatile compounds of polyolefin resin constructed in step 2 and the qualitative results, compare and analyze the odor compounds between different samples.

[0044] Based on the fingerprints and compound signal intensities after qualitative analysis described in step 4, the odor compounds of different brands of resins were compared and analyzed.

[0045] The qualitative results are shown in Table 1. A total of 75 volatile compounds were identified in the three resin brands, of which 50 odor compounds could be qualitatively characterized. The compounds included ketones, alcohols, aldehydes, acids, esters, benzene rings, alkenes, and alkanes.

[0046] Table 1 GC-IMS qualitative results of volatile compounds in three grades of polyolefin resins

[0047]

[0048]

[0049]

[0050]

[0051] Figure 1 The odor compound fingerprints of three different brands of polyolefin resins were obtained by testing. Combined with the strength of the response signals of each compound in the samples in Table 2, it can be concluded that there are 34 compounds detected in all three resin samples, including 20 qualitative odor compounds, namely ethanol, 2-acetone, 1-butanol, acetic acid, butyraldehyde, isopropanol, 2-methylpropanal, ethyl acetate, butyl acetate, 3-methylbutyric acid, cyclohexanone, propyl butyrate, 1-hexanol, butyl propionate, 2-methyl-1-butanol, butyl acetate, hydroxyacetone, ethylene glycol dimethyl ether, 2-methylpropionic acid, and propionaldehyde; there are 14 unqualified compounds, namely 4, 10, 13, 52, 32, 85, 15, 87, 97, 88, 31, 33, 40, and 71.

[0052] 2-Methylbutyric acid, ethyl butyrate, 2-methylbutyric acid, heptanoic acid, isovaleric acid, ethyl butyrate, 96, and 3-methylbutyric acid were detected in both H8020(after) and H8020(ago) resins, but not in 5000S resin. The two resins, H8020(after) and H8020(ago), are highly similar.

[0053] Depend on Figure 1 It can be seen that the brand 5000S resin is quite different from the other two resins, sarin, 1-propanol, 2-butanone, benzaldehyde, 34, 38, benzaldehyde, ethyl hexanoate, propyl butyrate, isoprene, 2-heptanone, 2-methylbutyric acid, 3-methyl-1-butanol, hexanenitrile, cyclohexanone, 84, valeraldehyde, butyraldehyde, 2-hexanol, 1-propanol, isobutyl acetate, 3-butenenitrile, valeraldehyde, 60, hexamethyldisiloxane, 80, butyl propionate, isopentanol, trans-2-hexenal, n-hexanol, 68, Pentan-1-ol, 2-methylpropionic acid, methyl isobutyl ketone, 2-hexanone, 75, ethyl 2-methylbutyrate, 3-methyl-1-pentanol, isopropyl 2-methylbutyrate, methyl 2-methylbutyrate, methyl isobutyl ketone, N-nitrosodiethylamine, 81, pentan-1-ol, 39, n-hexanol, trans-2-hexenal, and 3-methyl-1-pentanol have larger contribution values ​​in brand 5000S resin, and smaller detection signals in other brands of resins, and can be regarded as characteristic odor compounds of 5000S resin.

[0054] Table 2 Signal intensity of odor compounds of three different grades of resins

[0055]

[0056]

[0057]

[0058]

[0059]

[0060]

[0061] In summary, the application of headspace-gas chromatography-ion mobility spectrometry to the detection of odorous compounds in polyolefin resin materials offers the advantages of high sensitivity, high resolution, no pretreatment required, simple operation, short analysis time, and low detection cost. It can rapidly detect odorous compounds in polyolefin resin additive materials. The fingerprints generated by the LAV software can be compared and analyzed to visualize the differences in odorous compounds between samples. Establishing a method for studying odorous compounds in polyolefin resins based on headspace-gas chromatography-ion mobility spectrometry can provide data support and theoretical guidance for the development of new, low-odor, clean polyolefin resin materials.

Claims

1. A method for studying odor compounds in polyolefin resins based on headspace-gas chromatography-ion mobility spectrometry technology, characterized in that: Please follow the steps below to implement it: Step 1: subjecting the polyolefin resin to headspace-gas chromatography-ion mobility spectrometry detection; Step 2: Use the software LAV to extract the signal peaks of volatile compounds of different brands of resins and construct fingerprints; Step 3: Perform qualitative analysis on the signal peaks in the area selected in step 2 using the GC-IMS Library Search Software qualitative software; Step 4: The signal intensity of each compound in the odor compound fingerprint is used as the basis for comparing the odor substances of different brands of resins.

2. The method for studying polyolefin resin odor compounds based on headspace-gas chromatography-ion mobility spectrometry technology according to claim 1, characterized in that: The operation of headspace sampling in the headspace-gas chromatography-ion mobility spectrometry detection in step 1 is: Weigh 2 g of polyolefin resin sample into a headspace vial, incubate at 60°C, 500 rpm for 30 min, take 500 μL of headspace gas, and perform automatic headspace sampling.

3. The method for studying polyolefin resin odor compounds based on headspace-gas chromatography-ion mobility spectrometry technology according to claim 1, characterized in that: The ion mobility spectrometry detection conditions in the headspace-gas chromatography-ion mobility spectrometry detection in step 1 are: the inlet temperature is 85°C, the carrier gas is high-purity nitrogen with a purity of ≥99.999%, the flow rate program is as follows: 2 mL / min for 2 min, 20 mL / min for 8 min, 100 mL / min for 10 min, 150 mL / min for 40 min, and the total run time is 60 min.

4. The method for studying odor compounds in polyolefin resins based on headspace-gas chromatography-ion mobility spectrometry technology according to claim 1, characterized in that: The gas chromatography detection conditions in the headspace-gas chromatography-ion mobility spectrometry detection in the step 1 are: chromatographic column FS-SE-54-CB-1 capillary column, column length 15m, inner diameter 0.53mm, film thickness 1μm, column temperature 40°C, ion migration tube operating temperature 45°C, nitrogen flow rate 150mL / min, data acquisition in positive ion mode, using orthoketone C4~C9 as external standard reference.

5. The method for studying polyolefin resin odor compounds based on headspace-gas chromatography-ion mobility spectrometry technology according to claim 1, characterized in that: In step 2, the resin HS-GC-IMS test results are analyzed in the LAV software, and the signal peaks of volatile compounds in the sample are selected to construct a fingerprint spectrum of the polyolefin resin odor compounds.

6. The method for studying odor compounds in polyolefin resins based on headspace-gas chromatography-ion mobility spectrometry technology according to claim 1, characterized in that: The step 3 is to use the drift time, retention index, and retention time in the NIST14 database built into the GC-IMS Library Search Software instrument supporting software to perform qualitative analysis on the substance, and obtain the qualitative analysis results of the volatile compound signal peak.

7. The method for studying odor compounds in polyolefin resins based on headspace-gas chromatography-ion mobility spectrometry technology according to claim 1, characterized in that: In step 4, the qualitative analysis results based on the volatile compound signal peaks are combined with the constructed fingerprint to achieve a visual analysis of the differences in odor compounds between samples.

8. The method for studying polyolefin resin odor compounds based on headspace-gas chromatography-ion mobility spectrometry technology according to claim 1, characterized in that: The intensity of each signal peak in the fingerprint spectrum in step 4 is expressed as follows: the intensity of the odor substance with the highest content in the resin odor compound is set as 100, and the intensity of other compounds is expressed as a ratio to 100.

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