Determination of alkylphosphonic acids by microcolumn liquid chromatography with gradient elution coupled on-line with flame photometric detection

Microcolumn liquid chromatography with gradient elution and on-line flame p hotometric detection has been used for the selective and rapid determinatio n of non-volatile alkylphosphonic acids, which are hydrolysis products of n erve agents, in aqueous samples. A make-up of water was used to maintain st able introduction of the eluent during a gradient run. The detection limits are strongly dependent on quenching, which is determined by the mass flow of methanol in the eluent. Large-volume injections of 100 mul of aqueous so lutions of short- and long-chain alkylphosphonic acids resulted in detectio n limits in the range 6-800 ng/ml. The repeatability of the retention times and analyte response - peak area or peak height were 0.7-0.9% and 4-11%, r espectively. The method was successfully applied to a local tap water sampl e and an aqueous soil extract. (C) 2001 Elsevier Science B.V. All rights re served.