Identification of Polar, Ionic, and Highly Water Soluble Organic Pollutants in Untreated Industrial Wastewaters

Abstract

This paper presents a generic protocol for the determination of polar, ionic, and highly water soluble organic pollutants on untreated industrial wastewaters involving the use of two different solid-phase extraction (SPE) methodologies followed by liquid chromatography−mass spectrometry (LC-MS). Untreated industrial wastewaters might contain natural and synthetic dissolved organic compounds with total organic carbon (TOC) values varying between 100 and 3000 mg/L. All polar, ionic and highly water soluble compounds comprising more than 95% of the organic content [Betowski, L. D.; Kendall, D. S.; Pace, C. M.; Donnelly, J. R. Environ. Sci. Technol. 1996, 30, 3558] and with major contribution to the total toxicity of the sample cannot be analyzed by conventional gas chromatography−mass spectrometry (GC-MS), and LC-MS is a good alternative. In this work two extraction procedures were used to obtain fractionated extracts of the nonionic polar compounds: a polymeric Isolute ENV+ SPE cartridge for the preconcentration of anionic analytes and a sequential solid-phase extraction (SSPE) method percolating the samples first in octadecylsilica cartridge in series with the polymeric Lichrolut EN cartridge. Average recoveries ranging from 72% to 103% were obtained for a variety of 23 different analytes. Determination of nonionic pollutants was accomplished by reverse-phase liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (LC-APCI-MS), while anionic compounds were analyzed by ion pair chromatography-electrospray-mass spectrometry (IP-ESI-MS) and LC-ESI-MS. This protocol was applied to a pilot survey of textile and tannery wastewaters leading to the identification and quantification of 33 organic pollutants including phenolic compounds, benzothiazoles, nonionic surfactants (nonylphenol- and alcohol polyethoxylates and poly(ethylene glycol)), anionic surfactants (alkylbenzenesulfonates), benzene- and naphthalene sulfonates, and related industrial compounds. In the case of textile wastewaters, poly(ethylene glycol) (PEG), decyl alcohol polyethoxylate (C10EO5), and 2-naphthalenesulfonate were found as major pollutants in concentrations up to 1.2, 3.5, and 2.4 mg/L, respectively. Main contaminants in tannery wastewaters were poly(ethylene glycol), 4-chloro-m-cresol, diethylphthalate, and polyethoxylate tridecyl alcohol (C13EO4) with levels of 2.3, 2.3, 2.0, and 1.1 mg/L, respectively.