M8 PM Chiral Chemistry: Toxicology of Environmental Contaminants and Phase Transfer
Monday, 14 November 2005: 1:50 PM - 5:30 PM in 337-338

(WON-1117-844706) Enantiomeric composition of chiral pharmaceuticals in natural waters and wastewaters.

Wong, Charles¹, Nikolai, Lisa¹, MacLeod, Sherri¹, McClure, Evelyn¹, ¹ University of Alberta, Edmonton, AB, Canada

ABSTRACT- The occurrence and flux of stereoisomers of commonly used pharmaceuticals were determined in surface waters and wastewaters of the North Saskatchewan River and at Lac la Biche, Alberta, in order to understand the enantiomer composition of such chiral drugs in the aquatic environment. Chiral analysis has been extensively used in recent years to detect and gain insight into biologically-mediated processes affecting environmental pollutants. However, most of the work done to date has focused on legacy POPs (e.g., PCBs and organochlorine pesticides). Less emphasis has been placed on the plethora of current-use chemicals of emerging concern that are optically active, including pharmaceuticals. Surface water, wastewater, and sewage treatment plant effluent from a large city (North Saskatchewan River at Edmonton) and smaller population site (Lac la Biche) were extracted for target compounds using solid phase extraction, followed by chiral HPLC/MS/MS analysis under both positive (e.g., fluoxetine, paroxetine, omeprazole, temazepam) and negative (ibuprofen, ketoprofen, fenoprofen, metoprolol, propanolol) electrospray ionization. Enantiomer resolution ranged from 0.8 to 3.0 on a suite of chiral HPLC stationary phases (e.g., Chiralpak AD-RH, Chirobiotic V, Whelk-O 1). Achiral targets (e.g., clofibric acid, diclofenac, carbamazepine) were resolved from achiral targets, allowing for stereochemical information to be obtained at the same time as achiral quantitation. Detection limits were in the ng/L range, comparable to achiral HPLC/MS/MS analysis. Enantiomer fractions of target analytes were nonracemic and varied among surface waters and wastewaters, showing that insights on biological weathering of pollutants gained from legacy POPs are applicable to current-use chiral pharmaceuticals.

Key words: pharmaceuticals, enantiomers, HPLC/MS/MS, surface waters and wastewaters