Study On The New Analytical Method Of Different Species Of Organotin Compounds In Food

Organotin compounds(OTCs) are widely used in industry, agriculture, chemical industry and other fields as a kind of wood preservatives, antifouling paints, polyvinyl chloride(PVC) stabilizers, industrial catalysts and agricultural biocides. OTCs might cause the different degree pollution in food and deliberately be a risk to human health. Accordingly, it is great significant to establish the new analytical method of different species of organotin compounds in food. In this thesis, the different forms of orgaontins were extracted by novel extraction methods, such as microwave-assisted extraction, low-temperature pressurized liquid extraction, low-temperature precipitation procedure and dispersive-solid phase extraction. The determination of organotins in the final extracts was carried out by high performance liquid chromatography-inductively coupled plasma mass spectrometry(HPLCICP-MS), high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS) or gas chromatography-mass spectrometry(GC-MS).The methods also give technical support to monitoring food quality. The main results are as follows:1. A new low-temperaturepressurized liquid extraction(LTPLE) method was developed for extracting organotin compounds in water from Poyang Lake areas. Five organotin compounds including dimethyltin dichloride(DMT), dibutyltin dichloride(DBT), tributyltin chloride(TBT), diphenyltin dichloride(DPhT) and triphenyltin chloride(TPhT) were simultaneously extracted with dichloromethane using the LTPLE device, after being concentrated, the extracts were determined by HPLC-ICP-MS. The experimental parameters such as extraction solvent and the proportion of the aqueous phase and organic phase were optimized. In order to evaluate the accuracy of the developed method, the spiking experiments and HPLC-MS-MS were introduced. The limits of detection(LODs) of the five organotins were ranged from 0.029 to 0.049 μg/L, and the limits of quantification(LOQs) of the five organotins were ranged from 0.097 to 0.16μg/L, respectively. The proposed method was successfully applied to the simultaneous analysis of the organotins in water.2. A new analytical procedure for the simultaneous determination of five organotin compounds in several matrix wine samples was developed for the first time. The organotin compounds were extracted by microwave-assisted extraction(MAE) with n-hexane. Extraction conditions such as volume of n-hexane required, extraction temperature and extraction time were investigated and optimized by an orthogonal array experimental design. The determination of organotin compounds in the final extracts was carried out by HPLC-ICP-MS. The proposed procedure showed limits of detection between 0.029-0.049 μg/L. The linearity was in the range of 0.50-100 μg/L. The precision expressed as relative standard deviations(RSD) were below 9.43%. The developed method was successfully applied to determine different matrix wine samples, and some analytes were detected at the level of 0.053-1.14 μg/L.3. Triorganotin compounds which widely exist in seafood are huge risks to people’s health. Due to the trace amount in seafood, the detection of triorganotin compounds still faces large challenges in the complex matrix. In this study, a simple and rapid method has been successfully developed to extract trace amounts of triorganotin compounds in seafood by microwave-assisted extraction coupled with nanoparticles based magnetic clean-up. Based on this extraction method, four triorganotin compounds including triethyltin chloride, tributyltin chloride, triphenyltin chloride andazocyclotin were determinated by HPLC-ICP-MS. The various extraction conditions including temperature, time and volume of solvent were optimized to improve the extraction efficiency. Magnetic nanoparticles coated with octanoic acid were used to clean up the extracts. Under optimized conditions, the average recoveries(six replicates) of four triorganotins(spiked at 0.01, 0.02, 0.05 μg/g) were between 73.8% and 105.4%, and RSDs were less than 10.4%. The proposed procedure was successfully applied to analysis different seafood samples, and the compounds studied were detected in some seafood at 2.93-11.26 ng/g levels.4. A simple, low-cost method for the simultaneous determination of four organotins(DBT, DPhT, TBT and TPhT) in plant oil samples by GC-MS has been established. The method uses dispersive-solid phase extraction(d-SPE) clean-up after a low-temperature precipitation procedure, in situ derivatization with NaBEt4 and liquid-liquid extraction(LLE). The relevant experiment variables influencing the whole results were optimized respectively, the good accuracy and precision were attained under the optimal conditions. The average recoveries obtained for analytes were in the range of 83.5-104.3% with the relative standard deviation(RSD) of 2.87-7.91%, and the limits of detection for each organotin were ranged between 0.31 and 0.49 μg/L. Finally, the four organotins in different oil samples were detected using this method, which demonstrated the feasibility of our developed method in this study.5. A sensitive, selective and environmental friendly method for the determination of organotins in edible vegetable oil samples based on low-temperature precipitation process and HPLC-ICP-MS was developed and optimized. Four organotins including DBT, TBT, DPhT and TPhT were extracted with methanol simultaneously and purified by matrix solid-phase dispersion(MSPD) using graphitized carbon black. The experimental parameters such as extraction solvent and clean-up material were optimized. In order to evaluate the accuracy of the new method, the recovery was investigated. The procedures of extracting and purifying samples for the analysis were simple and easy to perform batch operations, also showed good efficiency with RSD. LODs of the four organotins were ranged from 0.28 to 0.59 μg/L, and LOQs of the four organotins were ranged from 0.93 to 1.8 μg/L, respectively. The proposed method was successfully applied to the simultaneous analysis of the four organotins in edible vegetable oil. Some analytes were detected at the level of 2.5-28.8 μg/kg.6. A method for the determination of DBT, TBT, DPhT and TPhT in edible vegetable oil samples based on low-temperature precipitation process and HPLC-MS-MS was established and optimized. 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 of 0.9967-0.9997. Under optimized conditions, the average recoveries of 74.2%-99.5% were obtained by three adding levels, and the relative standard deviations were 3.44%-8.26%. A satisfactory result was obtained in the determination of organotins in different kinds of edible vegetable oils.7. The different detection methods were evaluated in this chapter, including HPLC-ICP-MS, HPLC-MS/MS and GC-MS. The results demonstrated that there no significant differences among three detection techniques. HPLC-ICP-MS offers excellent sensitivity, wide linear dynamic range, high-speed analysis and no derivatization process, which was choosed to detect DBT, TBT, DPhT and TPhT in the different kinds of plant oils.