Study On Determination Of Different Forms Of Organotins In Food By Liquid Chromatography-Tandem Mass Spectrometry

Organotin compounds (OTCs) are characterised by the presence of one or more covalent bonds between atoms of carbon and tin (Sn-C) that have the general formula RnSnX4-n (n=1-4, R is an alkyl or aryl group). These compounds have shown considerable toxicity toward living organisms even at the fairly low content, and then their toxicity has aroused a particular attention of the social. At the early stage of research on the OTCs, the gas chromatograph and its coupled techniques were used widely, and the analytical target was focused on sediment, textile, leather, etc. But the study on the food is relatively limited. In the study, new analytical methods for the determination of varieties of OTCs in different food have been established, which was based on the pretreatment method of ultrasonic-assisted extraction (UAE) and dispersive solid-phase extraction (d-SPE) followed by the analysis with high performance liquid chromatography-tandem mass spectrometry. The main results are summarized as follows:1. A simple and accurate method was developed for the determination of triphenyltin and tributyltin in wine samples.10mL of wine simple was concentrated to about3.0mL under a gentle stream of nitrogen, and brought to volume of10mL with methanol, and then was filtered by0.22μm organic filter membrane. ZORBAX Eclipse plus C18column was used for the separation of organotin compounds, the mobile phase was methanol-0,1%methanoic acid (60:40, v:v), and the flow rate was0.3mL/min. The detection was operated in the positive ion mode using multiple reactions monitoring, and the two analytes was separated completely in3min. Under optimized conditions, good linearity was obtained when analytical concentrations were in the range of1～100ng/mL for TBT and TPhT, the linearity correlation coefficients (R2) was0.9992～0.9993. In the three spiked levels, the average recoveries of TPhT and TBT were ranged from77.5%to92.3%, with relative standard deviations (RSD) equal to or lower than10.08%. The proposed method was successfully applied to determine TPhT and TBT in the wine samples. 2. A reliable, simple and accurate analytical method was proposed for the simultaneous determination of three OTCs in seaweed.0.5g seaweed sample was taken into50mL centrifuge tube,20mL of the mixed solvent of dichloromethane-ethyl acetate (1:1, v:v) was added to extract for15min with ultrasonic-assisted extraction (UAE). Then the upper layer was transferred into20mL glass centrifuge tube, and concentrated to dryness under a gentle stream of nitrogen, then brought with the mixture solution of methanol and water (70:30, v:v) and filtered by0.22μm organic filter membrane. ZORBAX Eclipse plus C18column was used for the separation of OTCs, the mobile phase of HPLC was methanol-0.1%methanoic acid (55:45, v:v), the flow rate was0.3mL/min. The detection was operated in the positive ion mode using multiple reaction monitoring. It showed the good linearities when analytes concentration were in the range of1～100ng/mL, with the correlation coefficients (R2) in the range of0.9902～0.9918. For TMT TPhT and TBT, the detection limits were0.2,0.4and0.2ng/mL, respectively. In the two spiked levels, the average recoveries of TMT, TPhT and TBT were ranged from72.3%to98.0%, with relative standard derivation (RSD) less than8.1%. The results indicate this method is suitable for detecting TMT, TPhT and TBT in seaweed.3. A new method was established for the of determination trmethyltin (TMT), diphenyltin (DPhT), dibutyltin (DBT) and triphenyl tin (TPhT) and tributyltin (TBT) in fish by liquid chromatography-tandem mass spectrometry. ZORBAX Eclipse plus C18column was used for the separation of five OTCs, the mobile phase was methanol-formic acid/ammonium formate solution (pH=2.1), the flow rate was0.3mL/min. The gradient elution was applied as follows:0to4min, methanol-formic acid/ammonium formate solution (40:60, v:v);4to8.5min, gradually transformed to methanol-formic acid/ammonium formate solution (60:40, v:v);8.5to14min, methanol-formic acid/ammonium formate solution (60:40, v:v);14to17min, gradually transformed to methanol-formic acid/ammonium formate solution (40:60, v:v);17to20min, methanol-formic acid/ammonium formate solution (40:60, v:v). The detection was operated in the positive ion mode using multiple reaction monitoring. Good linearities was presented in the selected concentration range, the correlation coefficient is in the range of0.9943-0.9998, the detection limit of TMT, DPhT, DBT, TPhT and TBT was300ng/mL,140ng/mL,140ng/mL,1ng/mL and1ng/mL.