Evaluation of a gas chromatography-mass spectrometry method for the analysis of personal care products (PCPs) in wastewater.

Personal care products (PCPs) constitute a diverse group of chemicals that have recently been recognized as emerging contaminants of the aquatic environment, where they are continually introduced primarily by both untreated and treated sewage. They include compounds belonging to different chemical classes: surfactants in detergents (alkyl benzenes), fragrances in cosmetics (nitro and polycyclic musks), antioxidants and preservatives (phenols), plasticizers (phthalates). A multi-analytical method is required to determine these compounds and their bioactive metabolites in wastewater: even if LC/MS and LC/MS/MS are the most common analytical techniques for these soluble compounds, GC/MS and GC/MS/MS are sometimes used to identify and quantify volatile compounds and metabolites, in particular when resolution is mandatory to separate isomers or congeners. In the paper a GC/MS method is presented for the simultaneous analysis of PCPs belonging to different chemical classes in wastewaters: preconcentration and clean-up of the soluble components were performed using solid-phase extraction (SPE) prior to GC-MS determination. Due to the complexity of the aquatic environment where PCPs are introduced as complex mixtures, the chromatograms obtained from wastewater samples are complex signals whose interpretation can be difficult and time-consuming. Therefore, a signal processing procedure can be helpful to extract chemical information on the sample — number of components, abundance distribution — and separation — separation performance, retention pattern. Different extraction procedures were tested and compared, i.e., cartridge composition, solvent type and volume used to elute analytes from the cartridge in order to develop appropriate sample preparation and GC separation conditions to separate as many as possible components of the sample. The developed method may be the basis of wastewater monitoring for temporal and spatial changes of both target and non-target compounds. It will be also applied to monitoring the fate of PCPs in the wastewater treatment plant (WWTP) effluent to evaluate removal efficiency of PCPs in innovative treatment, i.e., constructed wetlands using natural processes involving wetland vegetation, filling media and their associated microbial colonias.