RP3 Design, Sampling, Measurement and Design
Thursday, 17 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(KAW-1117-866414) Liquid phase microextraction with in situ derivatization and GC-MS for measurement bisphenol A in river water samples.

Kawaguchi, Migaku¹, Ito, Rie¹, Endo, Naoyuki¹, Saito, Koichi¹, Nakazawa, Hiroyuki¹, ¹ Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Hoshi University, Tokyo, Japan

ABSTRACT- A novel method, based on liquid phase microextraction (LPME) with in situ derivatization and gas chromatography-mass spectrometry (GC-MS) is described for the determination of trace amounts of bisphenol A (BPA) in river water samples. Ten milliliters of river water sample was placed in a headspace vial containing surrogate standard. Then, 1 M potassium carbonate solution (1 ml) for pH adjustment, acetic acid anhydride (100 l) as the derivatization reagent, and a stir bar were added. The stirring was performed for 1 min. Then, the ultrasonication was performed for 3 min. A 10 l microsyringe was used for LPME. Before extraction, the syringe was rinsed with acetone followed by toluene 10 times to avoid carryover and air bubble formation. Four microliters of toluene was withdrawn into the syringe. The syringe needle tip was held 5 mm below the surface of a sample solution. LPME was performed at room temperature for 90 min while stirring at 1000 rpm. After the extraction, 2 l of extract was carefully withdrawn into the syringe. The extract was then injected into the GC-MS system. The detection limit and quantitation limit of BPA in river water samples is 2 and 10 ng l^-1 (ppt), respectively. Calibration for BPA was shown to be linear with a correlation coefficient of >0.999. The average recoveries of BPA in river water samples are higher than 95 % (RSD: < 10 %) with correction using an added surrogate standard, bisphenol A-¹³C₁₂. This simple analytical method may be applicable to the high sensitive determination of trace amounts of BPA in various liquid samples.

Key words: LPME, BPA, GC-MS, in situ derivatization