Determination of acetamiprid, imidacloprid, and spirotetramat and their relevant metabolites in pistachio using modified QuEChERS combined with liquid chromatography-tandem mass spectrometry

A QuEChERS based methodology was developed for the simultaneous identification and quantification of acetamiprid, imidacloprid, and spirotetramat and their relevant metabolites in pistachio by liquid chromato-graphy-tandem mass spectrometry for the first time. First, sample extraction was done with MeCN:citrate buffer: NaHCO3 followed by phase separation with the addition of MgSO4: NaCl. The supernatant was then cleaned by a primary-secondary amine (PSA), GCB, and MgSO4. The proposed method provides a linearity in the range of 5-200 mu g L-1, and the linear regression coefficients were higher than 0.99. LOD and LOQ were obtained to be 2 and 5 mu g kg(-1) for the studied insecticides, respectively, with the exception of imidacloprid-olefin (5 and 10 mu g kg(-1)). Acceptable recoveries (91-110%) were obtained for all the analytes with good intra-and interprecisions (0.4 >= RSD >= 11.0). The method was then used for the pistachio samples collected from a field trial to estimate the maximum residue limits (MRLs) in next step.