Bisphenol A (BPA) is one of the most widely produced compounds in the world and was listed as a substance of very high concern by the European Chemicals Agency in 2016. Because of its toxicity, many countries and regions, including China, have banned BPA addition in feeding-bottles. And the European Union (EU) has banned BPA use in other food contact materials and thermal paper. Restrictions on BPA have contributed to the widespread use of alternatives. As the toxicity of BPA alternatives continues to be revealed, the alternatives of BPA alternatives are being developing. As the most extensive alternative for BPA, bisphenol S (BPS) was proven to have estrogen-disrupting effects and developmental toxicity of the neuroendocrine system. Therefore, BPS alternatives are used in thermal paper. In this study, alternatives to both BPA and BPS are collectively referred to as bisphenols (BPs). As a pooling matrix of many indoor chemicals, dust is an important pathway for human exposure to BPs. BPA and its alternatives are routinely detected in dust. As BPS alternatives have been detected in recycled paper and sludge, it is also very important to detected in dust. However, common analytical methods for BPs have low sensitivity and contain few BPS alternatives. Therefore, a high-throughput, high-accuracy, and high-sensitivity method must be established for the determination of BPs in dust; this will lay the foundation for subsequent studies on the environmental behavior and exposure risk of BPs. In this study, an ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed for the simultaneous determination of 26 variations of BPs in dust. UPLC-MS/MS parameters of the variations were optimized to compare the separation effect and response intensity in different columns and mobile phases. The influence of the extraction solvent and solid phase extraction (SPE) on the extraction efficiency and purification effect of target compounds were optimized by using the isotopic internal standard method, and the 26 variations of BPs in dust was quantitatively analyzed. Finally, the dust samples were extracted by using 3 mL of acetonitrile and 3 mL of a 50% methanol aqueous solution in an ultrasound bath. The combined extract was further purified by using an Oasis HLB cartridge (60 mg/3 mL). The cartridge was then washed with a 40% methanol aqueous solution (0.5 mL) and eluted with methanol (2 mL). The target compounds were separated on a CORTECS® UPLC® C18 column (100 mm×2.1 mm, 1.6 μm), with methanol and 1 mmol/L ammonium fluoride solution as mobile phases and a flow rate of 0.3 mL/min. Electrospray ionization (ESI) was applied in the positive, negative, and multiple reaction monitoring (MRM) modes for the mass scan. Under optimized conditions, the linear ranges of the 26 targets behaved well linearly in their respective ranges with correlation coefficients (r2)>0.999. The limits of detection (LODs) and limits of quantification (LOQs) were assessed using signal-to-noise (S/N) ratios of 3 and 10, respectively. The LODs and LOQs of the method were 0.01-0.75 μg/kg and 0.02-2.50 μg/kg, respectively. The accuracy of the method was evaluated by conducting a recovery test at three spiked levels: LOQ, two times the LOQ, and 10 times the LOQ, with the average recoveries ranging from 83.7% to 114.9%. The precision of the method was evaluated by using the relative standard deviation (RSD). The intra-day RSDs and inter-day RSDs were 0.86%-9.79% (n=6) and 5.16%-19.5% (n=6), respectively. The established method was used to determine 11 dust samples. Fifteen BPs were detected at a detection rate of 9.1%-100.0%. The detection rate for BPA, BPS, bisphenol F (BPF), 4-hydroxy-4'-isopropoxydiphenylsulfone (BPSIP), and diphenyl sulfone (DPS) was 100.0%. BPSIP, 4-allyloxy-4'-hydroxydiphenyl sulfone (BPS-MAE), and bis-(3-allyl-4-hydroxyphenyl) sulfone (TGSA) were first detected in Chinese dust, whereas 4-benzyloxy-4'-hydroxydiphenyl sulfone (BPS-MPE), 4-hydroxybenzoic acid benzyl (PHBB), and DPS were first detected in dust samples worldwide. This method is simple, rapid, and sensitive, and is suitable for the qualitative screening and quantitative analysis of the 26 BPs in dust samples.
建立了一种超高效液相色谱-串联质谱(UPLC-MS/MS)同时测定灰尘中26种双酚类化合物(BPs)的多残留分析方法。实验通过优化26种BPs的色谱-质谱参数,比较了不同色谱柱和流动相的分离效果,同时考察了提取溶剂、固相萃取(SPE)等前处理条件对目标化合物的提取效率和净化效果的影响,再结合同位素内标法进行定量,实现了对灰尘中26种BPs的定量分析。灰尘样品依次用3 mL乙腈和3 mL 50%甲醇水溶液进行超声萃取,合并两次提取液,用6 mL超纯水稀释后通过Oasis HLB(60 mg/3 mL)固相萃取小柱,0.5 mL 40%甲醇水溶液淋洗,2 mL甲醇洗脱。以甲醇-1 mmol/L氟化铵水溶液为流动相,流速为0.3 mL/min,经CORTECS® UPLC® C18色谱柱(100 mm×2.1 mm, 1.6 μm)分离后,在电喷雾正、负离子多反应监测(MRM)模式下检测26种BPs。26种目标物在各自的范围内线性关系良好,相关系数(r2)>0.999,方法的检出限(LOD)为0.01~0.75 μg/kg,定量限(LOQ)为0.02~2.50 μg/kg。按LOQ、2倍LOQ和10倍LOQ 3个水平进行加标回收试验,回收率为83.7%~114.9%,日内相对标准偏差(RSD)为0.86%~9.79%(n=6),日间RSD为5.16%~19.5%(n=6)。对北京市生活区的11份灰尘样品进行检测,检出5种化合物。其中双酚A(BPA)、双酚S(BPS)、双酚F(BPF)、4-羟基-4'-异丙氧基二苯砜(BPSIP)和二苯砜(DPS)5种化合物的检出率为100.0%。该方法精密度好,灵敏度高,可对灰尘中26种BPs进行准确定性定量。
Keywords: bisphenols (BPs); dust; ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).