液相色谱-串联质谱法测定水环境中的十氯酮

建立了分析测定水环境中十氯酮的液相色谱-串联质谱法。水样经液液萃取、净化后，采用Eclipse plus C18柱（100 mm×2.1 mm，3.5 μm）分离，乙腈和水为流动相进行梯度洗脱，在电喷雾负离子多反应监测模式下进行检测，同位素内标法定量。结果表明：采用液相色谱-质谱联用技术，证实了十氯酮在甲醇中以半缩醛的形式存在，而在丙酮/乙腈中以偕二醇的形式存在。由于十氯酮极性较强，在净化时难以洗脱，并且不耐酸，所以不能与其他有机氯农药一起分析。十氯酮在5~100 μg/L范围有良好的线性关系，相关系数r²=0.999，检出限及定量限分别为0.70 ng/L和2.8 ng/L；在5、40和100 ng/L 3个浓度添加水平的平均回收率为95.1%~98.9%，相对标准偏差为3.85%~4.72%。本方法具有良好的灵敏度、回收率和重现性，适用于水环境中十氯酮的测定。

Determination of kepone in water by liquid chromatography-tandem mass spectrometry

An analytical procedure for the determination of kepone in water was described. Water samples were extracted by liquid-liquid extraction, and then cleaned-up. Chromatographic separation was performed on an Eclipse plus C18 column (100 mm×2.1 mm, 3.5 μm) with gradient elution using acetonitrile and water at a flow rate of 0.3 mL/min. The target compounds were determined in multiple reaction monitoring (MRM) mode via negative electrospray ionization (ESI^-) and quantified by isotopic-dilution technique. Results showed that kepone existed as diol form and hemiacetal in acetone/acetonitrile and methanol respectively, the structures of which were confirmed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Due to the polar nature of kepone, it was difficult to be eluted during clean-up procedure and it may be decomposed during sulfuric acid washing. Therefore, it could not be analyzed together with the other organochlorine pesticides. The calibration curve showed good linearity in the range of 5-100 μg/L with correlation coefficient (r²) of 0.999. The limit of detection was 0.70 ng/L and the limit of quantification was 2.8 ng/L in water. The average recoveries when spiked at 5, 40 and 100 ng/L in water were 95.1%-98.9%, and the relative standard deviations (RSDs) were 3.85%-4.72%. The method can be used to the determination of kepone in water due to its high sensitivity, good recovery and reproducibility.