Method for rapidly detecting monomer residual quantity in styrene polymer based on gas chromatography

Abstract

The invention discloses a method for rapidly detecting monomer residual quantity in styrene polymer based on gas chromatography, which belongs to the technical field of high polymer material analysis, and comprises the following steps: dissolving a styrene polymer sample in an organic solvent, adding an internal standard substance, uniformly mixing, and filtering to obtain a to-be-detected sample solution; a capillary chromatographic column is adopted, nitrogen is used as carrier gas, separation is performed in a programmed heating mode, and a hydrogen flame ionization detector is used for detection; an internal standard method is adopted for quantitative analysis, and the residual quantity of styrene in the styrene polymer is calculated according to the peak area ratio of styrene to an internal standard substance. The pretreatment process of the sample is simple, and only dissolving and filtering are needed, so that the pretreatment time is greatly shortened; an internal standard method is adopted for quantitative analysis, experimental errors are effectively eliminated, and precision and accuracy of the method are improved; the gas chromatography conditions are optimized, the sensitivity of the method is improved, and the detection requirement of low-content styrene residues can be met.

Description

Technical Field

[0001] This invention belongs to the field of polymer material analysis technology, and in particular relates to a method for rapid detection of monomer residues in styrene polymers based on gas chromatography. Background Technology

[0002] Styrene polymers (such as polystyrene, SBR, SBS, ABS, SEBS, SMA, SMI, etc.) are important polymer materials widely used in packaging, electronics, automobiles, building materials, and other fields. During their synthesis, small amounts of unreacted styrene monomers remain. Styrene is a toxic and hazardous substance, and its residue directly affects the performance and safety of styrene-based polymer materials (styrene is a suspected carcinogen). Currently, methods for detecting styrene residues mainly include gas chromatography and liquid chromatography. Among them, gas chromatography has advantages such as high sensitivity, good separation effect, and simple operation, making it a commonly used method for detecting styrene residues. However, existing gas chromatography methods for detecting styrene residues have the following shortcomings: 1. Complex sample pretreatment (such as dissolution-precipitation method, headspace method), which is time-consuming; 2. Insufficient detection sensitivity, making it difficult to meet the detection needs of low-content styrene residues. Summary of the Invention

[0003] To overcome the above problems, the present invention provides a method for rapid detection of monomer residues in styrene polymers based on gas chromatography, which is simple to operate, highly sensitive, precise and accurate.

[0004] The technical solution adopted in this invention is:

[0005] A rapid method for determining monomer residues in styrene polymers based on gas chromatography includes the following steps:

[0006] Step 1: Sample pretreatment: Dissolve the styrene polymer sample in an organic solvent, add the internal standard, mix well, and filter to obtain the sample solution to be tested;

[0007] Step 2: Gas chromatography analysis: A capillary column was used with nitrogen as the carrier gas, and separation was performed using a programmed temperature rise method. Detection was performed using a flame ionization detector (FID).

[0008] Step 3: Quantitative analysis: Quantitative analysis is performed using the internal standard method. Based on the peak area ratio of styrene and the internal standard, the residual amount of styrene in the styrene polymer is calculated.

[0009] In step one, the organic solvent is tetrahydrofuran or acetone.

[0010] In step one, the internal standard is n-dodecane.

[0011] In step two, the programmed temperature rise method is to start at 50°C, hold for 2 minutes, then raise the temperature to 250°C at a rate of 10°C / min, and hold for 5 minutes.

[0012] The advantages of this invention are as follows:

[0013] 1. The sample pretreatment process is simple, requiring only dissolution and filtration, which greatly shortens the pretreatment time;

[0014] 2. The use of the internal standard method for quantitative analysis effectively eliminates experimental errors and improves the precision and accuracy of the method;

[0015] 3. The gas chromatography conditions were optimized, improving the sensitivity of the method and enabling it to meet the detection requirements for low-content styrene residues. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a gas chromatogram of styrene and the internal standard n-dodecane according to the present invention;

[0018] Figure 2 This is the linear relationship graph of the standard curve of the present invention (x is the concentration of styrene, ranging from 0.1ppm to 100ppm; y is the peak area ratio of styrene to the internal standard n-dodecane). Detailed Implementation

[0019] Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0020] I. Instruments and Reagents:

[0021] Instruments: Gas chromatograph (equipped with FID detector), analytical balance (accuracy 0.1 mg), ultrasonic cleaner.

[0022] Reagents: Styrene standard (purity ≥99.9%), n-dodecane (internal standard), acetone (chromatographic grade).

[0023] II. Operating Procedures:

[0024] Preparation of standard solutions: Accurately weigh styrene standard and dilute it with acetone to prepare a series of standard solutions of 0.1, 1, 10, 50, and 100 ppm. Add 10 ppm of n-dodecane internal standard to each solution and mix well.

[0025] Sample pretreatment:

[0026] 1. Take 0.2g of polymer sample, add 10mL of acetone, and dissolve by sonication.

[0027] 2. Add 100 μL of internal standard solution (n-dodecane, 10 ppm) and mix well.

[0028] 3. Filter the solution through a 0.22 μm organic filter membrane to obtain the sample solution to be tested.

[0029] III. Gas Chromatography Conditions:

[0030] Injector temperature: 250℃.

[0031] Detector temperature: 280℃.

[0032] Column temperature program: Initial temperature 50℃, hold for 2 min, increase to 250℃ at a rate of 10℃ / min, hold for 5 min.

[0033] Carrier gas: nitrogen, flow rate 1.0 mL / min.

[0034] Injection volume: 1 μL.

[0035] Detector: FID.

[0036] Inject the sample under the chromatographic conditions described above, and record the retention time and peak area of ​​styrene and the internal standard.

[0037] IV. Data Processing:

[0038] Standard curve equation: y = 1.2503x + 0.008(R) 2 =0.9996), where y is the ratio of the peak area of ​​styrene to that of the internal standard, and x is the concentration of styrene (ppm).

[0039] The sample solution was analyzed by gas chromatography, and the peak areas of styrene and the internal standard were recorded. Based on the standard curve, the residual amount of styrene in the styrene polymer sample was calculated.

[0040] Example 1: The residual styrene content in a batch of ABS resin samples was 0.26 ppm, which deviated from the traditional headspace method (0.24 ppm) by less than 5%.

[0041] Example 2: The method of the present invention was used to detect the styrene residue in a batch of polystyrene (PS) samples. The results showed that the styrene residue was 0.5 ppm, the relative standard deviation (RSD) was 1.2%, and the spiked recovery rate was 98.7%-102.3%.

[0042] The results show that the method of the present invention is simple to operate, highly sensitive, precise and accurate, and can meet the detection requirements of styrene residue in styrene polymers.

[0043] The embodiments described above are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A rapid method for determining the residual amount of monomers in styrene polymers based on gas chromatography, characterized in that: Includes the following steps: Step 1: Sample pretreatment: Dissolve the styrene polymer sample in an organic solvent, add the internal standard, mix well, and filter to obtain the sample solution to be tested; Step 2: Gas chromatography analysis: A capillary column was used with nitrogen as the carrier gas, and separation was performed using a programmed temperature ramp method. Detection was performed using a flame ionization detector. Step 3: Quantitative analysis: Quantitative analysis is performed using the internal standard method. Based on the peak area ratio of styrene and the internal standard, the residual amount of styrene in the styrene polymer is calculated.

2. The method for rapid determination of monomer residues in styrene polymers based on gas chromatography according to claim 1, characterized in that: The organic solvent in step one is tetrahydrofuran or acetone.

3. The method for rapid determination of monomer residues in styrene polymers based on gas chromatography according to claim 1, characterized in that: The internal standard in step one is n-dodecane.

4. The method for rapid determination of monomer residues in styrene polymers based on gas chromatography according to claim 1, characterized in that: In step two, the programmed temperature rise method is to start at 50°C, hold for 2 minutes, then raise the temperature to 250°C at a rate of 10°C / min, and hold for 5 minutes.

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