Development of a Robust and Sensitive Method for Analyzing Butyltins, Phenyltins and Octyltins in Seafood

Abstract

A new method has been developed and validated for determination of ten organotin compounds (OTCs), including butyltins, octyltins, phenyltins, and tricyclohexyltin, in seafood that preserved the moiety of individual OTCs. The optimized method started with extraction of OTCs by acidified methanol solution and then cleaned up with Florisil solid-phase extraction (SPE). The OTCs in extract were finally derivatized with sodium tetraethylborate. The instrumental determination was carried out by a gas chromatograph coupled to an inductively coupled plasma mass spectrometer (GC-ICP/MS). Besides, gas chromatograph tandem mass spectrometry was also studied and evaluated for OTCs’ sensitivities. The method was validated with various seafood samples, including fishes, crustaceans and mollusks, according to Eurachem guidelines. An adequate linear relationship was obtained in the studied concentration range (0.125–12.5 μg Sn kg−1) in samples; the average spiked recovery values were in the range of 70–120% for the three levels of concentration studied in samples: 1.0, 1.5, and 2.0 μg Sn kg−1. Precision values, expressed as relative standard deviation, were lower than 10% at aforementioned spiking levels. The detection limits and quantification limits were below or equal to 0.25 and 1.0 μg Sn kg−1, respectively. Besides, certified reference material was used to assess the accuracy of the developed method. The developed method was successfully applied for the OTC determination in real samples.