Determination of a Variety of Organotin Compounds in Edible Vegetable Oil by Liquid Chromatography-Tandem Mass Spectrometry

Most organotin compounds, which have been widely used in food packaging materials and production process show serious toxicity effects on human health. A high content of fat brought large matrix interference to the analysis and detection of edible vegetable oil. Methanol was selected as the extraction solvent, and the edible vegetable oil in low temperature was easily solidified. A simple and low-cost method based on high performance Liquid Chromatography-Tandem Mass Spectrometry for the simultaneous determination of four organotins in edible vegetable oil samples was developed. Four organotins including dibutyltin dichloride, tributyltin chloride, diphenyltin dichloride and triphenyltin chloride were simultaneously extracted with methanol using the low-temperature precipitation process. After being concentrated, the extracts were purified by matrix solid-phase dispersion using graphitized carbon black. Ethanol, methanol, and acetonitrile were investigated to extract organotins from edible vegetable oil samples. The recoveries of the four organotins extracted by liquid-liquid extraction and freezing extraction were also compared. The proposed method is comparable to, or even an improvement on the current national standard and related research. The adsorption abilities of some materials including primary secondary amine, alumina N, florisil, and graphitized carbon black were also studied. In order to evaluate the accuracy of the new method, the recovery was investigated. The ranges in the recoveries for the four organotins present at three levels ranged from 74.2% to 99.5%. Current work is comparable or better than those of national standards and the reported methods. The results show that the sample preparation method enables the simultaneous determination of the four organotins in peanut oil, soybean oil, corn oil, rape oil and edible blended oil samples.