Determination of the pyrethroid inseticide metabolite 3-phenoxybenzoic acid in wastewater using polar organic integrative samplers and LC-MS/MS analysis

Wastewater-based epidemiology (WBE) is a methodological approach that aims to obtain epidemiological in-formation through wastewater analysis, by identifying endogenous metabolism products. Pyrethroid insecticides are commonly used but just a few studies evaluated concentrations of pyrethroid metabolites in wastewater. A cost-effective and efficient sampling strategy for WBE studies is the use of polar organic chemical integrative samplers (POCIS). This study aimed to develop and evaluate a method for estimating the concentration of the pyrethroid insecticide 3-phenoxybenzoic acid (3-PBA) using POCIS sampling and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. The sampler sorbent was extracted with methanol, followed by a double solid phase extraction (SPE) clean-up. The extraction procedure had yields in the range of 95.7-100.4 %. There were 27 collection cycles, with POCIS samplers changed every 14 days. The analyte 3-PBA was measured in all collections. The concentration of 3-PBA in the POCIS sorbent was 208.6-2456.9 ng g-1. The sampling rate was 0.096 L/day and the resulting estimated concentration in wastewater was 24.3 to 335.2 ng/L. This is the first study evaluating POCIS sampling to measure a pyrethroid metabolite in water or wastewater samples.

Automated summary

Wastewater-based epidemiology (WBE) is a method that obtains epidemiological information by analyzing wastewater. This study developed a method to estimate the concentration of a pyrethroid insecticide metabolite using POCIS sampling and LC-MS/MS analysis. The concentration of the metabolite in POCIS sorbents was 208.6-2456.9 ng g-1, with an estimated concentration in wastewater of 24.3 to 335.2 ng/L.