Phthalates as plasticizers and cold-resistant agents have been widely used in plastic products, but their carcinogenicity has also attracted increasing attention. Therefore, it is necessary to analyze and study the content of plasticizer. In this paper, gas chromatography (GC) is applied to the dimethyl phthalate (DMP), diethyl phthalate (DEP), and dibutyl phthalate (DBP) in polyvinyl chloride (PVC) materials. , Benzyl phthalate (BBP), bis (2ethylhexyl) phthalate (DEHP), diisononyl phthalate (DINP), di-n-octyl phthalate (DNOP) ), Diisodecyl phthalate (DIDP) and other 8 kinds of phthalate residues were measured. The method is simple, rapid and sensitive. Animal Traps,Coil Spring Trap,Kill Animal Trap,Mouse Trap Hebei Liebang Metal Products Co.,Ltd , https://www.liebangtraptool.com
1 Experimental part
1.1 Instruments and reagents Gas chromatograph GC5890F, equipped with hydrogen flame ionization detector (FID).
Dichloromethane: analytically pure. Phthalate Standard Substance
1.2 Chromatographic analysis conditions Special chromatographic column; temperature program: 80 ℃ 20 ℃ / min 200 ℃ 5 ℃ / min 220 ℃ (1min) 20 ℃ / min 300 ℃ (3min). Detector temperature: 340 ℃, inlet temperature: 320 ℃; gas pressure: N2 total pressure 260kPa, carrier gas N2 pressure 180kPa, H2 pressure 65kPa, air pressure 55kPa; septum purge flow rate: 5 ~ 10mL / min; split flow Pneumatic flow rate: 50 ~ 100mL / min; injection volume: 1μL.
1.3 Preparation of standard solution Dichloromethane is used to prepare phthalate into a mixed standard stock solution with a mass concentration of 5g / L. When used, it is diluted with dichloromethane to a series of mass concentrations (0.005, 0.01, 0.05, 0.1, 0.5g / L) standard working fluid. Another set of mixed solutions containing only DINP and DIDP, the mass concentration of which is 0.05, 0.1, 0.5, 1, 2g / L.
1.4 Sample preparation Cut the PVC material into 2 ~ 3mm long scraps, accurately weigh 1.000g, use dichloromethane as a solvent, use a Soxhlet extractor to extract the phthalate, and extract the extract after 2h Make up to 25 mL with dichloromethane. Analyzed by capillary gas chromatograph and gas chromatography-mass spectrometer, qualitative based on retention time and mass spectrometry, and quantified by gas chromatography external standard method, of which DINP and DIDP are semi-quantitative by peak group area integration method or quantified by respective characteristic ion peak area .
2 Results and discussion
2.1 Standard chromatogram According to the above analysis conditions, the mixed standard solution of 8 plasticizers with a mass concentration of 0.5g / L is analyzed, and the chromatograms of the 8 plasticizers obtained
2.2 Qualitative analysis Based on the comparison between the retention time of the chromatographic peak of the sample to be tested and the retention time of the calibration standard sample to determine the presence or absence of each component of the plasticizer. In order to ensure the accuracy of the identification of each component peak, the spiked component peak can be judged by the addition method.
2.3 Quantitative analysis Use external standard method to quantify the linear relationship between peak area and phthalate mass concentration. (slightly)
2.4 Determination of samples The actual samples were measured according to the method established in this article, and it was found that DINP and DIDP are generally present in PVC materials, and the content of other components is very small. Occasionally DMP or DEP are false positives. The following heating procedure can be adopted: 80 ℃ 10 ℃ / min200 ℃ 20 ℃ / min300 ℃ (3min) respectively measure the sample and the spiked sample, correct the standard, you can judge the true or false positive. For DINP and DIDP, peak group integration is used, and the method of increasing the sensitivity by 10 times is used for semi-quantitative analysis.