Optimizing gas chromatographic-mass spectrometric analysis of selected pharmaceuticals and endocrine-disrupting substances in water using factorial experimental design.
An analytical method based on gas chromatography-mass spectrometry (GC-MS) has been developed to simultaneously determine selected acidic and neutral pharmaceuticals and endocrine-disrupting substances in surface and tap water. Solid-phase extraction (SPE) with Oasis HLB cartridges is followed by derivatization of the target analytes in the eluted extract. Derivatization was systematically optimized by employing a factorial experimental design. More specifically a central composite design was applied to search for the optimal conditions of the derivatization process and it was demonstrated that N-methyl-N-tert-butyl-dimethysilyl-trifluoroacetamide (MTBSTFA) had a better overall performance compared to N,O-bis(trimethylsilyl) trifluoroacetamide (BSTFA). The influence of solvent ratios and elution volumes while using SPE were also studied using a factorial design. The method was developed successfully for most of the selected compounds [i.e. ibuprofen, salicylic acid, gemfibrozil, naproxen, triclosan, propranolol, diclofenac, carbamazepine, 4-octylphenol (OP), 4-nonylphenol (NP), nonylphenol-monoethoxylate (NP1EO), nonylphenoxyacetic acid (NP1EC), estrone (E1), and 17alpha-ethinyloestradiol (EE2)]. Relative recoveries for spiked river and tap water ranged from 47 to 130% and 60-109%, respectively. Typical limits of detection were less than 5 ng/L in tap water and less than 10 ng/L in river water. Twelve target compounds were detected in river and tap water samples using the developed method. This method is currently used in bench-scale drinking water treatment studies.
Yu
Zirui
Z
NSERC Chair in Water Treatment, Department of Civil and Environmental Engineering, University of Waterloo, 200 University Avenue W., Waterloo, Ontario N2L 3G1, Canada. z2yu@uwaterloo.ca
Peldszus
Sigrid
S
Huck
Peter M
PM
D052244:Endocrine Disruptors / Q000032:analysis* / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D015394:Molecular Structure; D004364:Pharmaceutical Preparations / Q000032:analysis / Q000737:chemistry*; D015203:Reproducibility of Results; D012107:Research Design; D052616:Solid Phase Extraction; D012997:Solvents / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry
D052244:Endocrine Disruptors; D004364:Pharmaceutical Preparations; D012997:Solvents; D014874:Water Pollutants, Chemical