| Summary: | 碩士 === 淡江大學 === 水資源及環境工程學系 === 89 === Mostly, the traditional extraction method (liquid-liquid extraction) was used as pretreatment in the determination of the organotin in seawater and sediments. The analytical method also consisted of derivation, clean-up, preconcentraion procedures, followed by gas chromatography(GC) detection. The whole processes were complex and time-consuming. In this study, the headspace solid phase microextraction (SPME) combined open-focus microwave-assisted extraction and gas chromatography- ion trap mass spectrometry (GC-ITMS) determination were presented. This new analytical method is solvent free and easy to operate, with the potential that we can use it to analyze a large number of samples within a short period of time (usually less than one hour.)
The SPME experiments were designed to use mix level orthogonal array to find six optimized operation factors. The dibutyltin(DBT) and tributyltin(TBT) were as the target compounds, and the optimized factors were that adsorption time, 50 min; sample pH, 4.1; maximum stirring speed, scale 3; adsorption temperature, 25℃; salt concentration, 2%; and desorption time, 2 min.The extracts were analysed by GC-ITMS. The result was similar to those in the documents related. The detection limits for mono-butyltin(MBT), DBT and TBT were 55.5 ng Sn/L, 26.4 ng Sn/L and 5.7 ng Sn/L, respectively.
The real seawater samples from Fisherman Wharf in Tamshui were analysed to do spiked experiment . The results were obtained that the extraction recovery rates of MBT, DBT, and TBT were all more than 90%. Also, the real seawater samples from five suspected heavily-polluted sea area were collected and we found that the concentrations of TBT were between 10.5 ng Sn/L and 85.4 ng Sn/L.
As for sediment extraction and analysis, the optimized microwave extraction conditions established in the previous related researches in our lab were used as microwave power, 60w; microwave time, 3min;extraction solvent, acetic acid (1+1). Than, the digested liquid was transfered to SPME procedure as above. Both spike experiment and the determination of CRM-462 samples were conducted. The recovery rates of DBT and TBT in the spike experiment were about 70% and 80%, respectively, and in CRM-462 samples were only 60% and 55%.
|
|---|
