Determination of sulfonic acids and alkylsulfates by ion chromatography in water

A fast ion chromatographic method with suppressed conductivity detection has been developed for the simultaneous determination of methane-, ethane-, 1-propane-, 1-butane-, 1-pentane-, 1-hexane-, 1-heptane-, 1-octane-, 1-nonane-, 1-decane-, 1-dodecane-, dodecylbenzene-, p-toluene-, benzenesulfonic acids, octylsulfate and dodecylsulfate in water samples. Due to the high number of analytes and their heterogeneity, the effect of the mobile phase parameters (NaOH, CH3OH and CH3CN concentration) on the retention factors has been studied in detail, so achieving, for the first time, the separation among 15 of these analytes by a gradient elution. Detection limits included within 0.06-0.16 μM have been obtained. Interferences from Cl-, NO3- and SO42-, possible anions present in water samples, have been considered and a SPE procedure has been developed for analytes enrichment and matrix removal in a seawater sample. This is the first application of an ion-exchange chromatographic method to a seawater sample for this kind of analytes.