Two-dimensional liquid chromatography - mass spectrometry as an effective tool for assessing a wide range of pharmaceuticals and biomarkers in wastewater-based epidemiology studies.

The biomarkers used in wastewater-based epidemiology studies have a wide range of physicochemical properties, making simultaneous analysis extremely challenging or even impossible. So far, the majority of analytical procedures employed in this field have focused on specific classes or a limited number of analytes. The heart-cutting two-dimensional liquid chromatography tandem mass spectrometry technique (2D-LC-MS/MS) has enabled the incorporation of compounds with significantly different polarities in a single analytical method. In this study, a 2D-LC-MS/MS method has been developed and optimized for the simultaneous analysis of various biomarkers in wastewater, providing relevant information about lifestyle habits (the usage of alcohol, tobacco, and caffeine), health and well-being (pharmaceuticals), and a population size biomarker (5-HIAA) that is useful for correct calculation of human population during wastewater-based epidemiology studies. A single-laboratory validation procedure showed satisfactory analytical performance, with the mean trueness for most compounds falling in the range of 80÷110 % and the mean repeatability being less than 20 %. The applicability of the method was evaluated by testing 28 wastewater samples collected at different wastewater treatment plants in Latvia. The obtained results revealed the occurrence of 44 out of 62 selected biomarkers, with the lowest quantified concentration at 1.1 ng L-1 in the case of xylometazoline and up to 148 μg L-1 in the case of metformin and 156 μg L-1 for caffeine.