Identification and quantitation of diethylstilbestrol in aquatic products using gas chromatography coupled with triple quadrupole tandem mass spectrometry

We developed a highly sensitive and specific method for determining DES residue in fish meat using gas chromatography coupled with tandem mass spectrometry (GC-MS-MS) with a triple quadrupole analyzer (QqQ). The samples were extracted using ethyl acetate, cleaned using florisil, and derivatized using a mixture of 99% N, O-bis(trimethylsilyl) trifluoroacetamide (BSTFA) and 1% trimethylchlorosilane (TMCS). The results showed that the GC-MS-MS system presented great advantages for the identification and quantitation of DES in fish meat. The limit of detection (LOD) and limit of quantification (LOQ) values were 0.0142 mu g kg(-1) and 0.0475 mu g kg(-1), respectively. The recoveries from the spiked fish samples spiked at four levels were in the range of 86.1% to 106%. The precision of the method was evaluated using the relative standard deviation (RSD) and ranged from 1.39% to 9.62%. The linear range was from 1.00 to 100 mu g L-1 with good linearity (r = 0.9998). It can be concluded that the method is reliable for identifying and detecting DES residue at trace levels in aquatic products.