On-line solid-phase extraction-ion-pair liquid chromatography-electrospraymass spectrometry for the trace determination of naphthalene monosulphonates in water

This paper presents an HPLC-MS method for the fully automated determination of a group of naphthalene monosulphonates in environmental water samples. The analytical procedure consisted of on-line ion-pair solid-phase extracti on using a PLRP-S precolumn and ion-pair LC separation with triethylamine a s ion-pair reagent in both cases. A mass spectrometric detector, coupled to LC through an electrospray interface and operated in negative ion mode, wa s used. Diagnostic ions usually corresponded to [SO3](-) and/or [M-SO2H](-) together with [M-H](-) and/or [M-2H+Na](-). The method was applied to the trace determination of several sulphonates present in tap water, seawater a nd water from the Ebro river. The analytes were determined at a concentrati on level between 0.05 and 1 mu g 1(-1) under selected ion monitoring acquis ition by preconcentrating just 15 mi of sample. Naphthalene-l-sulphonate an d naphthalene-2-sulphonate were identified and quantified in one of the sam ples of seawater. (C) 1999 Elsevier Science B.V. All rights reserved.