超高效液相色谱-串联质谱法测定水稻基质中阿维菌素残留量

建立了超高效液相色谱-串联质谱法(UPLC-MS/MS)测定水稻基质中阿维菌素残留量,考察了基质效应,并对实际样品进行了检测.稻田土、稻壳、糙米和稻杆经乙腈振荡提取,稻田水经乙酸乙酯液液分配提取后,用C18固相萃取小柱或弗罗里硅土柱净化,采用UPLC-MS/MS正离子扫描测定残留的阿维菌素.稻田土、稻田水和糙米的3种添加浓度(1.0,10.0和100 μg/kg或μg/L)的平均回收率为84％～107％,相对标准偏差为4.7％～13.6％.稻壳和稻杆的2档添加浓度(10.0和100 μg/kg)的平均回收率为90％和103％,相对标准偏差为8.4％～12.9％.本方法在稻田水、糙米和稻田土中的检出限为0.3μg/kg在稻壳和稻杆中检出限为3.0 μg/kg,低于欧盟和日本在稻米中制定的阿维菌素最大残留限量值.阿维菌素在2.0～100 μg/L范围内线性关系良好( r＞ 0.999).

Determination of Abamectin Residue in Paddy Rice by Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry

A new method for the confirmation and quantification of abamectin residues in paddy rice was established based on ultra performance liquid chromatography-tandem mass spectrometry.The matrix effects for the method were studied.Paddy soil,paddy hull,brown rice and rice straw were extracted with acetonitrile by an oscillator,and cleaned up by C18 SPE cartridge or florisil column.Paddy water was extracted with ethyl acetate by liquid-liquid partition,and cleaned up by C18 SPE cartridge.The detection was performed by tandem mass spectrometry with electrospray ionization in positive mode(ESI+).Average recoveries of paddy soil,paddy water and brown rice at three spiked levels(1.0,10.0 and 100 μg/kg,or μg/L) were found in the range of 84%-107% with RSD<13.6%.Average recoveries of paddy hull and rice straw at two spiked levels(10.0 and 100 μg/kg) were found in the range of 90%-103% with RSD<12.9%.Limits of detection(LODs)of abamectin in paddy soil,paddy water and brown rice were 0.3 μg/kg,which were lower than the maximum residue limit(MRL) established by the Japanese and the European legislation in rice(10 μg/kg).Limits of detection(LODs) of abamectin in paddy hull and rice straw were 3.0 μg/kg.A good linear relationship was obtained in the range of 2.0-100 μg/L with the correlation coefficient(r) over 0.999.