Quantitative determination of bisphenol-A in river water by cool-on-column injection gas chromatography mass spectrometry

A sensitive and selective method is described for the simultaneous quantitation and confirmation of bisphenol-A (BPA) in river water to support a surface water analysis study. The method employs a cool-on-column injection, gas chromatographic separation and detection by electron impact mass spectrometry (COC-GC-MS). River water samples (40 mt) were fortified with a stable isotope internal standard, deuterium labeled analog of BPA (Ds-BPA). The sample was then extracted with toluene and the extract was concentrated (400X) prior to analysis by COC-GC-MS. The analysis involves detection of the M+ ion and the [M-CH3](+) ion (base peak) with quantitation based on the [M-CH3](+) ion response. The quantitation limit, with confirmation, for BPA for this method was determined to be 1 mu g BPA/L of river water. Confirmation of BPA was determined by monitoring the ratio of the M+ ion to the [M-CH3](+) ion. Calibration curves for standard concentrations of 1 mu g/L to 20 mu g/L resulted in correlation coefficients (r(2)) of 0.9981 to 0.9999. The extraction/concentration efficiency for this method was determined to be 81.5%. Relative recoveries of BPA from river water ranged from 84% to 113% with an overall average of 102% +/- 7% (1 to 20 mu g/L). This method was developed to support a surface water analysis study to determine the level of BPA in surface water at five sites which use BPA in a manufacturing process and was sponsored by the Bisphenol-A Task Group of The Society of the Plastics Industry, Inc.