Analytical upgrade of a methodology based on UHPLC-MS/MS for the analysis of endocrine disrupting compounds in greywater

A multi-residue analytical methodology for the determination of 25 endocrine disrupting compounds (EDCs), encompassing various chemical classes (hormones, antimicrobials, preservatives, plasticizers, stimulants, alkylphenolic compounds, anticorrosives, and organophosphorus flame retardants), has been upgraded for the analysis of greywater. The methodology is based on solid phase extraction (SPE) followed by ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The optimized methodology achieved recoveries between 63% and 146% for all compounds, with MDLs ranging from 0.3 to 141 ng/L. Most of the compounds showed a pronounced signal suppression in the laundry greywater tested, and therefore, quantification was performed with a matrix-matched calibration curve to surpass the matrix effects observed (between -100% and 106%). Additionally, polyvinylidene fluoride (PVDF) membrane filters were selected among several filter types as the most suitable for greywater filtration. The upgraded methodology allowed the detection of 14, four and four EDCs in laundry, kitchen and shower/sink greywater, respectively. Caffeine was the only compound detected in all types of greywater, showing the highest concentrations (> 40,000 ng/L in kitchen greywater, and 2,360 ng/L in laundry greywater), followed by methylparaben and 1H-benzotriazole (1,607 and 776 ng/L, respectively, in laundry greywater). This analytical methodology constitutes an important tool for monitoring different families of contaminants in greywater, a poorly studied matrix, which is nowadays being considered as a future source of freshwater, contributing to overcoming problems of water scarcity. Water monitoring thus helps to guarantee water quality in water reuse practices and to understand EDC exposure patterns and their potential environmental impact.