超快速液相色谱-串联质谱法测定空气中微量小分子醛

Determination of trace low molecular mass aldehydes in air by ultra-fast liquid chromatography-tandem mass spectrometry

目的建立准确、灵敏的空气中微量乙醛、丙烯醛、甲基丙烯醛、丁烯醛的超快速液相色谱-串联质谱测定方法。方法采用酚试剂作为吸收液,考察了酚试剂的衍生化条件包括酚试剂浓度、pH、衍生化时间和温度对衍生效率的影响,研究了衍生物的稳定性、质谱裂解机制、方法的基质效应和采样效率。衍生物在Shim-pack XR-ODS II色谱柱(100 mm×2.0 mm, 2.2μm)上,以甲醇-水为流动相进行梯度洗脱,采用电喷雾电离源在多反应监测正离子模式下测定,外标法定量。结果乙醛、丙烯醛、甲基丙烯醛和丁烯醛在1.00~100μg/L(以醛计)的测定范围均具有良好的线性,相关系数(r2)≥0.9990,低、中、高3个添加浓度的加标回收率为90.6%~97.8%,精密度为1.9%~6.4%(n=6),平均采样效率为91.0%~97.1%,以采集10 L空气计,空气中乙醛、丙烯醛、甲基丙烯醛和丁烯醛的最低定量检测浓度均为0.5μg/m3。结论建立的方法简便、干扰少、特异性强,可用于测定作业场所空气中的微量乙醛、丙烯醛、甲基丙烯醛和丁烯醛。

OBJECTIVE To establish a rapid and accurate method for the determination of trace acetaldehyde, acrolein, methacrylaldehyde, crotonaldehyde in the air by ultra-fast liquid chromatography-tandem mass spectrometry(UFLC-MS/MS). METHODS The air sample was concentrated and derivatived by 3-methyl-2(3 H)-benzothiazolonhydrazone(MBTH), and the effect of derivative conditions including the concentration of MBTH,the pH, the derivative time and temperature was investigated. The stability of derivatives, the cracking mechanism of mass spectrometry, the matrix effect of the method and air sampling efficiency were studied. The chromatographic separation was carried out on a Shim-pack XR-ODS II column(100 mm×2.0 mm, 2.2 μm) by using water/methanol solution as the mobile phase with the gradient elution. Detection was performed in positive multi-reaction monitoring(MRM) mode for quantification by using external standard method. RESULTS The four analytes showed good linear relationship within the range of 1.00-100 μg/L(calculated by aldehyde) with a correlation coefficient r≥0.9990. The limits of quantitation(LOQs) of the method(concentrated with 10 L air) were 0.5 μg/m3 in air, for acetaldehyde, acrolein, methacrylaldehyde, crotonaldehyde. The recoveries of the method were 90.6%-97.8% at the three spiked levels, and the relative standard deviations(RSDs) were between 1.9%-6.4%(n=6), the average sampling efficiency was between 91.0%-97.1%. CONCLUSION The developed method is simple, less interference and specificity, and is suitable for the simultaneous rapid determination of trace acetaldehyde, acrolein, methacrylaldehyde, crotonaldehyde in air of work place.