Determination of steroids and coprostanol in surface water, effluent and mussel using gas chromatography-mass spectrometry

A method was developed for the determination of coprostanol and steroids, including estradiol-17 beta, estrone and testosterone in surface water, effluent and mussels. The method is based on the derivatization of steroids containing hydroxyl groups with pentafluorobenzyl bromide (PFB-Br), followed by gas chromatography-mass spectrometric (GC-MS) determination. Estradiol-17 beta and estrone were successfully derivatized by this method, whereas coprostanol (a sterol compound) and testosterone showed no spectra of the derivatized form, and were therefore determined as free compounds. Surface water and effluent were extracted by liquid-liquid extraction using dichloromethane, while mussels were extracted using a microwave extraction system. The method detection limits of estradiol-17 beta, estrone, testosterone and coprostanol were 2 ng L-1 for surface water and effluent, and 3ng g(-1) for mussel. Recoveries in spiked reagent water and mussel for the same chemicals ranged from 56 to 87% and 21 to 48%, respectively. Using this method, Estradiol-17 beta, estrone and coprostanol were detected in surface water, taken from the St. Lawrence River, at concentrations ranging from 2 to 67 ng L-1. Only coprostanol was found in effluent and mussel samples at concentrations of 14667 ng L-1 and 32252 ng g(-1), respectively.