固相萃取/液相色谱-串联质谱法测定水中苯胺类化合物及基质干扰的消除

建立了固相萃取/液相色谱-串联质谱检测水中18种苯胺类化合物的分析方法,并优化了固相萃取和色谱条件。水样经混合型阳离子交换柱(MCX)或硅胶基体阳离子交换柱(SCX)富集后,用氨水甲醇溶液洗脱,用超纯水适当地稀释后,用液相色谱-串联质谱法测定。以ODS柱为分离柱,甲醇-0.005%(v/v)甲酸水溶液为流动相,梯度洗脱,多反应监测模式分析,内标法定量。18种苯胺类化合物的分析时间在15 min之内。采用MCX柱萃取时,16种苯胺化合物的方法检出限为0.002~0.035 μ g/L,地表水样品的加标回收率为72.5%~92.5%,相对标准偏差为1.4%~9.6%;采用SCX柱萃取时,17种苯胺类化合物的方法检出限为0.013~0.207 μ g/L,地表水样品的加标回收率为66.5%~102%,相对标准偏差为2.4%~13.6%。本实验还考察了消除基质干扰的5种方法,结果表明,调整色谱分离条件是最有效的方法,其次是选择合适的前处理方法。更换离子源、内标法定量和利用基质标准溶液校正也可在一定程度上消除或补偿基质干扰。

Determination of aniline derivatives in water by solid phase extraction/liquid chromatography-tandem mass spectrometry and elimination of matrix interference

A method was developed for the determination of 18 aniline derivatives (ADs) in water by liquid chromatography-tandem mass spectrometry (LC-MS/MS) coupled with solid phase extraction. The water sample was enriched by a mixed cation exchange column (MCX) and a silicon substrate cation exchange column (SCX). The column was eluted by ammonia methanol solution. The eluent was concentrated and then diluted with purified water to the appropriate multiple. The separation of ADs was performed on an ODS column, and the mobile phase of methanol-0.005% (v/v) formic acid aqueous solution was employed with gradient elution, then the analytes were detected by LC-MS/MS in multiple reaction monitoring mode, with internal standard method for quantitative analysis. The analysis of the 18 ADs was completed in 15 min and the calibration curves showed good linearity. When an MCX was employed for extraction, the method detection limits of the 16 ADs ranged from 0.002 to 0.035 μ g/L, the average recoveries and relative standard deviations of the 16 ADs in surface water were 72.5%-92.5% (n=6) and 1.4%-9.6% (n=6), respectively. When an SCX was employed for extraction, the method detection limits of the 17 ADs ranged from 0.013 to 0.207 μ g/L, and the average recoveries and relative standard deviations of the 17 ADs in surface water were 66.5%-102% (n=6) and 2.4%-13.6% (n=6), respectively. During the development of this method, five elimination methods of matrix interference were studied. The results showed that adjustment of chromatographic separation conditions is the most efficient method, and the selection of appropriate method for sample preparation is the second one. The replacement of ion source, internal standard method and calibration by matrix matched standard solution can eliminate and compensate matrix interference to some extent.