Simultaneous determination of MCPA-isooctyl and its metabolite MCPA in maize by ultra-performance liquid chromatography-tandem mass spectrometry
An ultra-high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS)method was developed for the simultaneous determination of MCPA-isooctyl and its metabolite MCPA residues in maize(fresh maize,maize kernel and maize stover).The samples were acidified with hydrochloric acid,extracted with acetonitrile,cleaned-up by NH2-SPE column,analyzed by UPLC-MS/MS in multiple reaction monitoring(MRM)mode,and quantified by external standard method.The results showed that the average recoveries of MCPA-isooctyl and MCPA were in the range of 82%~107%at the spiked levels of 0.01~0.5 mg/kg with the relative standard deviations(RSDs)of 0.81%~8.9%.The limits of detection(LOD)of the method were 0.38~1.42 μg/kg and the limits of quantification(LOQ)were 1.28~4.76 μg/kg.The method is reliable and sensitive,and meets the requirements of pesticide residue analysis,and it can achieve the simultaneous detection of MCPA-isooctyl and its metabolite MCPA in corn.