QuEChERS结合气相色谱-串联质谱法测定室内灰尘中的37种液晶单体化合物

Determination of 37 Liquid Crystal Monomers in Indoor Dust by Us⁃ing QuEChERS Coupled with Gas ChromatographyTandem Mass Spectrometry

建立了一种简单易行且灵敏准确的测定室内灰尘中液晶单体化合物(Liquid crystal monomers,LCMs)的方法。灰尘样品中加入^(13)C-多氯联苯和^(13)C-多溴联苯醚作为内标,采用二氯甲烷进行提取,萃取液加入无水硫酸钠后采用混合吸附剂(N-丙基乙二胺和十八烷基键合硅胶)净化,随后采用气相色谱-串联质谱在动态多反应监测(dMRM)模式下测定,内标法定量。对仪器分析参数、提取溶剂和吸附剂进行了优化。结果显示在优化条件下,37种液晶单体在0.1~50 ng/mL范围内线性良好,方法检出限为0.02~1.56 ng/g;在两加标水平下的平均回收率为65.3%~137%,相对标准偏差(RSD)为0.90%~24%。通过对实际样本的检测,发现在北京所采集的室内灰尘中有22种LCMs的检出率在50%以上,表明室内环境已普遍存在LCMs污染。该方法操作简单,溶剂消耗少,灵敏度和稳定性良好,可用于大规模室内环境污染监测。

Liquid crystal monomers(LCMs)are a group of manmade chemicals used in display devic⁃es,while their wide use has caused environmental pollution and health risks.In this study,a sim⁃ple,sensitive and accurate analytical methodology was established for the determination of LCMs in indoor dust.For the sample pretreatment,dust samples were mixed with stable isotope substituted in⁃ternal standards(ISs),namely polychlorinated biphenyls(^(13)C-PCBs)and polybrominated biphenyl ethers(^(13)C-PBDEs),and then extracted by dichloromethane(DCM),and the supernatant was subse⁃quently transferred to another tube after centrifugation.With anhydrous sodium sulfate adding into the extracted solution,the solution was further purified by a mixture absorbent of primary secondary amine(PSA)and octadecyl-modified silica(C_(18)).Finally,37 LCMs were simultaneously tested on a gas chromatography-tandem mass spectrometry performed under dynamic multi-reaction monitoring mode(dMRM),and the internal standards were used for quantification.Instrumental parameters,the use of extraction solvents and absorbents were optimized.Under the best condition,the 37 LCMs exhibited good linearity in the range of 0.1-50 ng/mL,with a method detection limit of 0.02-1.56 ng/g.The average recoveries of the tested substances at two spiking levels was 65.3%-137%,with relative standard deviations(RSDs)of 0.90%-24%.Twenty real indoor dust samples collected in Bei⁃jing were tested.The contents of total LCMs in dust ranged from 38.9 to 125 ng/g,and the average contents of the individual LCMs were from 0.0447 to 25.1 ng/g.Twenty-two LCMs out of the 37 tar⁃get LCMs presented relatively high detection frequency(higher than 50%),which indicated the ubiq⁃uity of LCMs in indoor environment in Beijing.With the spread of smart electronic devices,it is fore⁃seeable that the pollution of LCMs in indoor environment will be rather serious.The analytical method developed in our study presented multiple advantages including simple operation,low solvent con⁃sumption,good sensitivity and stability,and it is suitable for large-scale indoor environmental pollu⁃tion monitoring.