The determination of pharmaceutical and personal care products in water and wastewater by gas chromatography-mass spectrometry

Abstract

Emerging contaminants (EC) are unregulated substances that have entered the environment for as long as they have been produced through human activities. Within the ECs family, pharmaceuticals and personal-care products (PPCPs) is a class of the most common pollutants employed in everyday urban activities. Current regulatory approaches are inadequate to address these contaminants and the presence of such chemicals in the aquatic environment and their potential deleterious effects has received an increasing attention from the public and scientific community. Influent and effluent wastewater from Daspoort Waste Water Treatment Works (WWTW), which treats wastewater from the central Pretoria area, were sampled and analysed from January to December 2015 for pharmaceuticals and personal care products by gas chromatography time of flight mass spectrometry (GC/TOF-MS). Thirteen pharmaceuticals were selected for focused study in wastewater which include; (acetaminophen, bisphenol A, carbamazepine, diclofenac, 17α-estradiol, 17β-estradiol, estriol, famciclovir, fenoprofen, ibuprofen, primidone, progesterone and testosterone) based on the criteria of their prescription volumes in both private and public health sector in South Africa. The development of a sensitive and reliable analytical method for the simultaneous determination of PPCPs in aquatic samples was carried out; using a combined solid-phase extraction (SPE) isolation and clean-up, followed by derivatization prior to GC/TOFMS determination. A seven points concentration levels linear calibration curve with correlation coefficient (R2) ranged from 0.9988 to 0.9999 was obtained. The limits of detection (LOD) and the limit of quantification (LOQ) ranged from 0.01-0.27 μg L-1 and 0.03-0.91 μg L-1 respectively for target PPCPs. Repeatability studies gave % RSD within 3.41 – 11.72 % for peak area. The % RSD values for reproducibility studies were 2.88 – 9.91% for peak area over the three concentrations (ibuprofen: 0.4, 2 and 8 μg L-1) evaluated during 5 days. These results indicated that the proposed method has excellent precision as evidenced by very stable peak area for the analytes. The recovery testing carried out, exhibited recoveries ranging from at least 82-115% and 81-115 % in tap water and Milli-Q water respectively, with % RSD less than 12%, showing that the overall PPCPs determination method including the extraction procedure was a repeatable method.. The method was applied to target PPCPs from Daspoort influent and effluent wastewater in Pretoria (South Africa). Natural hormones and antiviral drug were not detected in all the samples analysed by this method. Bisphenol A, acetaminophen, carbamazepine, ibuprofen and diclofenac were detected at low concentrations, ranging from 0.052-135.42 μg L-1 in wastewater. The level of bisphenol A, primidone, carbamazepine, ibuprofen and diclofenac in effluent wastewater were found to be lower in comparison to the influent. Several other non-target compounds, such as benzophenone, caffeine, methocarbamol, efavirenz, atrazine, dioxaphetyl butyrate, nevirapine, androsta-1,4-diene-3,17-dione, cis-tramadol, batyl alcohol, paredrine, 7-acetyl-6-ethyl-1,1,4,4-tetramethyltetralin, propylparaben, eugenol, cholesterol, stigmasterol, guaifenesin, benzyl benzoate, 4-tert-octylphenol, diethyltoluamide, dicyclomine, terbuthylazine, spiroxamine, bis(2-ethylhexyl) phthalate, bumetrizole , were also detected in the wastewater sample using the developed method.