A simple extraction method for the simultaneous detection of tetramisole and diethylcarbamazine in milk, eggs, and porcine muscle using gradient liquid chromatography-tandem mass spectrometry

Analysis of residual quantities of contaminants in foods of animal origin is crucial for quality control of consumer products. This study was aimed to develop a simple and raid analytical method for detection of tetramisole and diethylcarbamazine using gradient liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS). Tetramisole, diethylcarbamazine, and guaifenesin (as an internal standard) were extracted from milk, eggs, and porcine muscle using acetonitrile followed by partitioning at -20 degrees C for 1 h. No extract purification was deemed necessary. The analytes were separated on C18 column using ammonium formate both in water and methanol. Good linearity was achieved over the tested concentration range with R-2 >= 0.974. Recovery at two fortification levels ranged between 67.47% and 97.38%. The intra- and inter-day precisions were 20%. The limit of quantification was 0.2 and 2 ng/g for tetramisole and diethylcarbamazine, respectively. An analytical survey of samples purchased from large markets showed that none of the samples contained any of the target analytes. To the best of our knowledge, this is the first report on the quantitative determination of tetramisole and diethylcarbamazine in animal food products. (C) 2015 Elsevier Ltd. All rights reserved.