Identification, quantification and distribution of substituted phenols in the dissolved and suspended phases of water samples by gas chromatography tandem mass spectrometry: Derivatization, mass fragmentation and acquisition studies

In this paper, due to our new working strategy approach, the identification and quantification of 26 substituted phenols (SPs), including chlorophenols (CPs), methyl and nitro phenols (MPs, NPs, respectively), the technical mixture of 4-nonylphenol, triclosan and bisphenol-A were described. Selected species were determined both in the dissolved and suspended phases of samples as their trimethylsilyl-ether derivatives, developing a step by step, cautiously tuned, gas chromatographic tandem mass spectrometric (GC-MS/MS) method applying multiple reaction monitoring (MRM) acquisition. This procedure proved to be suitable for the quantitation of candidate species in the range of 0.29 ng/L (4-chloro-3,5-dimethylphenol) to 14 ng/L (2-methylphenol) levels. As a novelty to the field, the characteristic presence of SPs in tap waters as well as their distribution between the dissolved and suspended phases (henceforth; dissolved substituted phenols (DSPs) and suspended substituted phenols (SSPs) of Danube River and wastewater samples were confirmed. It means that SSPs - obtained by filtering water samples on glass fiber papers, prior to their solid phase extraction (SPE), these insoluble, however integral and unfortunately in the overwhelming cases of analyses discarded part of water pollutants - were identified and quantified, simultaneously. For this purpose our new, time, labor, cost effective and quantitative, ultrasound assisted extraction process for the analysis of SSPs was introduced and validated. Reproducibility, reliability and practical applicability of our working strategy were proved by the proportionality of the DSP and SSP contents, determined simultaneously from different sample volumes, characterized with the relative standard deviation percentages (RSD%) of analyses. The analytical performance characterization of our protocol was completed also by the classical recovery process. We added to 1 L Danube River waters 150 and 400 ng/L, while to 100 mL effluent wastewater samples 500 and 1000 ng/L SP standards; in all cases performing three parallel spiking tests of each average recoveries proved to be 86% (Danube River) and 84% (effluent wastewater), respectively. Partition of SPs between the dissolved and suspended phases of Danube River and influent and effluent wastewaters, meaning, the total amount of SPs (DSPs + SSPs) that the ecosystem is faced of, was defined for the first time. Distribution of found SPs revealed that their considerable part, in thorough correlation with their solubilities, is present in suspended phases; in average, 82% in wastewater and 57% in Danube River samples. (C) 2014 Elsevier B.V. All rights reserved.