Applicability of the direct injection liquid chromatographic tandem mass spectrometric analytical approach to the sub-ngL-1 determination of perfluoro-alkyl acids in waste, surface, ground and drinking water samples

Lorenzo Ciofi; Lapo Renai; Daniele Rossini; Claudia Ancillotti; Alida Falai; Donatella Fibbi; Maria Concetta Bruzzoniti; José Juan Santana-Rodriguez; Serena Orlandini; Massimo Del Bubba

doi:10.1016/j.talanta.2017.08.052

Applicability of the direct injection liquid chromatographic tandem mass spectrometric analytical approach to the sub-ngL^-1 determination of perfluoro-alkyl acids in waste, surface, ground and drinking water samples

Talanta. 2018 Jan 1:176:412-421. doi: 10.1016/j.talanta.2017.08.052. Epub 2017 Aug 17.

Affiliations

¹ Department of Chemistry - University of Florence, Via della Lastruccia 3, Sesto Fiorentino, 50019 Florence, Italy.
² Publiacqua S.p.A., Via di Villamagna 90/c, 50126 Florence, Italy.
³ GIDA S.p.A., Via Baciacavallo 36, 59100 Prato, Italy.
⁴ Department of Chemistry - University of Turin, Via Pietro Giuria 7, 10125 Turin, Italy.
⁵ Department of Chemistry - University of Las Palmas de Gran Canaria, 35017 Las Palmas de Gran Canaria, Spain.
⁶ Department of Chemistry - University of Florence, Via della Lastruccia 3, Sesto Fiorentino, 50019 Florence, Italy. Electronic address: delbubba@unifi.it.

PMID: 28917770
DOI: 10.1016/j.talanta.2017.08.052

Abstract

The applicability of a direct injection UHPLC-MS/MS method for the analysis of several perfluoroalkyl acids (PFAAs) in a wide range of water matrices was investigated. The method is based on the direct injection of 100µL of centrifuged water sample, without any other sample treatment. Very good method detection limits (0.014-0.44ngL^-1) and excellent intra and inter-day precision (RSD% values in the range 1.8-4.4% and 2.7-5.7%, respectively) were achieved, with a total analysis time of 20min per sample. A high number of samples - i.e. 8 drinking waters (DW), 12 ground waters (GW), 13 surface waters (SW), 8 influents and 11 effluents of wastewater treatment plants (WWTP_IN and WWTP_OUT) were processed and the extent of matrix effect (ME) was calculated, highlighting the strong prevalence of |ME| < 20%. The occurrence of |ME| > 50% was occasionally observed only for perfluorooctanesulphonic and perfluorodecanoic acids. Linear discriminant analysis highlighted the great contribution of the sample origin (i.e. DW, GW, SW, WWTP_IN and WWTP_OUT) to the ME. Partial least square regression (PLS) and leave-one-out cross-validation were performed in order to interpret and predict the signal suppression or enhancement phenomena as a function of physicochemical parameters of water samples (i.e. conductivity, hardness and chemical oxygen demand) and background chromatographic area. The PLS approach resulted only in an approximate screening, due to the low prediction power of the PLS models. However, for most analytes in most samples, the fitted and cross-validated values were such as to correctly distinguish between | ME | higher than 20% or below this limit. PFAAs in the aforementioned water samples were quantified by means of the standard addition method, highlighting their occurrence mainly in WWTP influents and effluents, at concentrations as high as one hundred of µgL^-1.

Keywords: Direct injection UHPLC-MS/MS; Drinking water; Environmental water; Matrix effect chemometrics; Perfluoroalkyl acids; Wastewater.

MeSH terms

Chromatography, High Pressure Liquid / methods*
Drinking Water / analysis
Environmental Monitoring
Fatty Acids / analysis*
Fluorocarbons / analysis*
Fresh Water / analysis
Limit of Detection
Sulfonic Acids / analysis*
Tandem Mass Spectrometry / methods*
Wastewater / analysis
Water Pollutants, Chemical / analysis*

Substances

Drinking Water
Fatty Acids
Fluorocarbons
Sulfonic Acids
Waste Water
Water Pollutants, Chemical