OPTIMIZATION OF SUPERCRITICAL FLUID EXTRACTION/HEADSPACE SOLID-PHASE MICROEXTRACTION AND GAS CHROMATOGRAPHY-MASS SPECTROMETRY METHOD FOR DETERMINATING ORGANOTIN COMPOUNDS IN CLAM SAMPLES

For the food safety of sea products, the variables of headspace solid-phase microextraction (HS-SPME) and supercritical fluid extraction (SFE) were optimized for the determination of organotin compounds in clam samples by method of off-line SFE/HS-SPME and gas chromatographic analysis with mass spectrometry (GC-MS). The best result was obtained while the spiked clam sample was extracted at 45C and 30 MPa with carbon dioxide modified with 5% (mol) methanol at 1.2 L/min (as carbon dioxide in ambient pressure) for 15 min, and SFE extract was ethylated with 2% (w/v) sodium tetraethylborate (NaBEt4) in pH 4 buffer solution and simultaneously adsorbed by HS-SPME with polydimethylsiloxane-divinylbenzene (PDMS/DVB) fiber at 50C for 30 min, followed by GC-MS. The whole sampling and analyzing process was within 1 h, and only less than 10 mL of solvent were used. The results were comparable with those obtained by traditional method which use of methanol (contain 0.03% tropolone), and the procedure also seems to be less time-and labor-consuming. The pollution of OTCs in seafood indicated a potential danger for the health of the local people who cared for these foods.