PMID- 27978474 OWN - NLM STAT- MEDLINE DCOM- 20170313 LR - 20191210 IS - 1873-376X (Electronic) IS - 1570-0232 (Linking) VI - 1040 DP - 2017 Jan 1 TI - Simultaneous determination and identity confirmation of thiodicarb and its degradation product methomyl in animal-derived foodstuffs using high-performance liquid chromatography with fluorescence detection and tandem mass spectrometry. PG - 97-104 LID - S1570-0232(16)30897-2 [pii] LID - 10.1016/j.jchromb.2016.12.013 [doi] AB - A high-performance liquid chromatography-fluorescence detection method was developed for the simultaneous determination of thiodicarb and its degradation product methomyl in animal-derived food products, including chicken muscle, beef, pork, table eggs, and milk. Thiodicarb is known to degrade during analysis; therefore, a thorough investigation was carried out, revealing that thiodicarb degrades to methomyl immediately after spiking into a matrix of animal-derived food products. Consequently, thiodicarb was determined as the sum of the parent compound and methomyl. Samples were extracted with acetonitrile and sodium salts, and purified using solid-phase extraction (SPE). The limits of detection (LODs) and quantification (LOQs) were 0.0013 and 0.004mg/kg, respectively, for both analytes in various matrices. Seven-point external calibration curves were obtained, and they showed excellent linearity with determination coefficients (R(2))>/=0.999 for all tested matrices. The method was validated at three fortification levels (LOQ, LOQx2, and LOQx10) in triplicate with average recoveries ranging from 84.24 to 112.8% (for methomyl) and relative standard deviations (RSDs)