Determination of five estrogens in wastewater using a comprehensive two-dimensional gas chromatograph

Abstract

Comprehensive two-dimensional gas chromatography (GC × GC) hyphenated with rapid quadrupole mass spectrometry was successfully used to develop a novel method for the determination of trace level estrogens in influent and effluent wastewater. Five estrogens used for the study were 17β-estradiol (βE2), 17α-estradiol (αE2), estrone (E1), 17α-ethynylestradiol (EE2) and estriol (E3). Two orthogonal columns and thermal modulation result in enhanced separation, while the rapid scanning quadrupole mass spectrometer gives high resolution peaks. Samples were extracted with Hydrophilic–Lipophilic Balance (HLB) cartridges and derivatized with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) prior to analysis. The method uses a single extraction step and ng L⁻¹ method detection limits were achieved using a relatively low sample volume of 500 mL. Elimination of additional cleanup steps make the method time effective. Furthermore, the method has less initial cost as the instrument is far less expensive than a tandem mass spectrometer. A parallel conventional gas chromatographic-mass spectrometric (GC/MS) study was carried out to compare the results. Detection limits were 2 to 4 times improved with the GC × GC over the GC/MS.