Simultaneous determination of 19 triazine pesticides and degradation products in processed cereal samples from Chinese total diet study by isotope dilution-high performance liquid chromatography-linear ion trap mass spectrometry

A selective and sensitive isotope dilution-high performance liquid chromatography-linear ion trap mass spectrometry (Isotope Dilution-HPLC-LIT-MS3) method was developed for the simultaneous determination of 19 triazine pesticides and their degradation products in processed cereal samples from Chinese total diet study (TDS). The method integrated the addition of isotope internal standards, liquid-liquid extraction (LLE), clean-up with MCX solid-phase extraction (SPE) cartridges and HPLC-LIT-MS3 analysis with selected reaction monitoring (SRM) mode. Matrix-matched calibration curves showed good linearity (R-2 >= 0.9940) verified by applying the Mandel's fitting test (p > 0.087) performed at the 95% confidence level. Decision limits (CC alpha s) and detection capabilities (CC beta 5) of the 19 triazine pesticides and their degradation products fell in the ranges of 0.0020-0.4200 mu g kg(-1) and 0.0024-0.4500 mu g kg(-1), respectively. Recoveries ranged from 70.1% to 112.8%, with the relative standard deviations (RSDs) ranging from 1.5% to 13.5%. Furthermore, the proposed method was applied to analyzing the proposed cereal samples from the fourth Chinese TDS. Eleven triazines were detected in six cereal samples with the concentrations ranging from 0.013 to 0.987 mu g kg(-1). This method can also be used for the further determination of the triazines in other food group composites, and ultimately served as a methodological foundation for assessing the triazines in the average Chinese diet in the general population. (C) 2013 Elsevier B.V. All rights reserved.