Residue Analysis of the Pharmaceutical Diclofenac in Different Water Types Using ELISA and GC−MS

Abstract

A highly sensitive and specific indirect competitive enzyme-linked immunosorbent assay (ELISA) for the determination of diclofenac in water samples was developed. With pure water, the limit of detection (LOD, S/N = 3) and IC50 were found to be 6 ng/L and 60 ng/L, respectively. The analytical working range was about 20-400 ng/L. Highest cross-reactivity (CR) of 26 tested pharmaceuticals, metabolites, and pesticides was found for 5-hydroxydiclofenac (100%). Other estimated values were well below 4% and, therefore, are negligible. The assay was applied for the determination of diclofenac in tap and surface water samples as well as wastewater collected at 20 sewage treatment plants (STPs) in Austria and Germany. Humic substances were identified as main interference in surface water. Wastewater samples which were only submitted to filtration and dilution yielded about 25% higher diclofenac concentrations using the ELISA compared to GC-MS. However, the ELISA turned out to be a simple, inexpensive, and accurate method for the determination of diclofenac both in influent and effluent wastewater after rather simple sample preparation, i.e., filtration, acidification, and readjustment to neutral pH-value, and at least 10-fold dilution with pure water.

Photochemical characteristics of diclofenac and its photodegradation of inclusion complexes with β-cyclodextrins

“…3 Within the aquatic environment, in river and surface waters, diclofenac is one of the most frequently detected pharmaceuticals. 4 Diclofenac is considerably stable under normal environmental conditions and the most probable decomposition pathway for its onsite elimination is photodecomposition. [5][6][7][8] Investigation of the photolysis of labile environmental pharmaceutical contaminants is important in environmental chemistry because it presents basic data on their fates and persistence in natural environments exposed to sunlight action.…”

Quality of Human Urine Used as Fertilizer: Case of an Ecological Sanitation System in Ouagadougou Peri-Urban Areas-Burkina Faso

“…These values are superior to the detection limit of 0.5 ng/l, for analyzing environmental samples [19]. In the absence of regulation on the occurrence of steroid hormones in effluents, it is difficult to compare our results to others.…”

“…The wavelengths used for measurements were between 283.8 nm and 357.9 nm. Steroid hormones (pregnandiol, estrone) were analysed in each centrifugated urine sample, using ELISA method as described by Deng et al [19].…”

An indirect competitive enzyme-linked immunosorbent assay for determination of norfloxacin in waters using a specific polyclonal antibody

“…The blocking buffer should be carefully selected because it is used to prevent non-specific absorbance [29]. Two blocking reagents (OVA and casein) prepared with PBS at a concentration of 1% and a Kem-En-Tec synthetic blocking buffer were tested for their blocking capacity.…”