The prevalently used LC–MS/MS methods for the simultaneous determination of synthetic phenol antioxidants (SPAs) and relevant metabolites suffer from a serious drawback of low sensitivity for 2,6-di-tert-butyl-4-hydroxytoluene (BHT) and a common issue of background contamination, which hampers the simple and accurate detection of these substances at trace levels in environmental samples. In this study, we developed an improved LC–MS/MS method for the simultaneous determination of eight SPAs and four relevant metabolites, including BHT. By use of atmospheric pressure chemical ionization (APCI), the sensitivity of BHT in the LC–MS/MS was enhanced approximately 260 times versus results obtained by using electrospray ionization (ESI), which allowed the analysis of BHT up to 1.1 ng/g in indoor dust and 0.06 ng/g in human plasma. Similarly, the sensitivity of 2,4,6-tri-tert-butylphenol and 2,6-di-tert-butyl-4-sec-butylphenol was also enhanced with APCI, which avoided their separate analysis by GC–MS. By installation of a C₁₈ column after the eluent mixer and before the injector as a trap column, the target analytes leached out from the LC system were eluted at a much later retention time than those in the samples, which resulted in complete elimination of the instrumental background contamination. These improvements enable the method to be well applied to the real samples.

中文翻译：

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改进的LC-MS / MS方法利用常压化学电离和捕集柱同时测定合成的苯酚抗氧化剂和相关代谢物

在普遍使用的LC-MS / MS方法合成的酚抗氧化剂（SPA）和相关代谢物的同时测定从低灵敏度的一个严重的缺点遭受2,6-二叔丁基-4-羟基甲苯（BHT）和背景污染的常见问题，这妨碍了在环境样品中以痕量水平对这些物质进行简单而准确的检测。在这项研究中，我们开发了一种改进的LC-MS / MS方法，用于同时测定8种SPA和4种相关代谢物，包括BHT。通过使用大气压化学电离（APCI），与使用电喷雾电离（ESI）所获得的结果相比，LC-MS / MS中BHT的灵敏度提高了约260倍，这使得BHT的分析速度高达1.1 ng / g在室内灰尘中的含量为0.06 ng / g，在人体血浆中的含量为0.06 ng / g。同样，2,4,6-三-的灵敏度叔丁基苯酚和2,6-二-叔丁基-4-仲丁基APCI还增强了丁基丁基苯酚，避免了用GC-MS对其进行单独分析。通过在洗脱液混合器之后和进样器之前将C ₁₈色谱柱安装为捕集柱，从LC系统中滤出的目标分析物的洗脱时间比样品中的保留时间晚得多，从而完全消除了样品中的残留物。仪器背景污染。这些改进使该方法可以很好地应用于实际样品。