固相萃取-超高效液相色谱-串联质谱法测定育苗水中矮壮素和助壮素残留量及其消解动态

建立了育苗水中矮壮素和助状素的固相萃取-超高效液相色谱-串联质谱法(SPE-UPLC-MS/MS)测定方法。样品直接采用弱阳离子固相萃取柱净化;在粒径5μm的亲水作用色谱柱上用SeQuant ZLC-HILIC MEKCK色谱柱进行分离;电喷雾正离子(ESI+)模式电离,多反应监测(MRM)模式检测。以保留时间和特征离子定性、外标法定量。结果表明矮壮素和助状素在0.2~10 ng/mL的空白添加浓度范围内线性良好(r2>0.999),在2.0、5.0、10ng/mL的添加水平范围内,平均回收率分别为89.1.0%~107.1%和102.3%~105.4%,相对标准偏差(RSD)分别为8.5%~29.5%和5.5%~23.0%,矮壮素和助壮素的检出限(LOD)为0.005ng/mL,测定低限(LOQ)为0.02ng/mL,水体中矮壮素和助状素的消解动态研究结果表明,矮壮素和助状素在水体中消解速度缓慢,施药42天后才能减少到96%以上。

Study on Chlormequat and Mepiquat Residues and their dissipation trends in seeding water by Accelerated Solvent Extraction-Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry

A method for determination of chlormequat and mepiquat in seeding water by accelerated solvent extraction-Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry（ASE-UPLC-MS/MS） was established.The sample was cleaned up by WCX solid phase extraction column;The target compounds were separated on SeQuant ZLC-HILIC MEKCK.The residues of chlormequat and mepiquat were obtained under the electrospray ionization in positive ion mode（ESI＋） and multiple reaction monitoring（MRM） mode;The matrix-matched external standards calibration curves were used for quantitative analysis,retain time and feature ion were used for qualitative determination.The linear range was 0.2~10μg/kg and the correlation coefficients（r2） was no less than 0.9990,The average recoveries of chlomequat and mepiquat from seeding water in the three spiked range of 2.0,5.0 and 10.0μg/kg were in the range of 89.1.0%~107.1% and 102.3%~105.4% respectively with relative standard deviations in the range of 8.5%~29.5% and 5.5%~23.0% respectively.The limits of detection and limits of quantitation for the target compounds were 0.2ng/mL and 0.001ng/mL respectively.With the established method,the dissipation rate of chlormequat and mepiquat in water was studied,showing that the target compounds will decrease to 96% or more at about 42days.