MICROCOLUMN PRECONCENTRATION AND GAS-CHROMATOGRAPHY MICROWAVE-INDUCED PLASMA-ATOMIC EMISSION-SPECTROMETRY (GC-MIP-AES) FOR MERCURY SPECIATION IN WATERS

A novel method for the direct determination of mercury species at the ng l(-1) level in natural waters is described. Methyl-, ethyl- and inorganic mercury are preconcentrated on a sulphhydryl cotton microcolumn incorporated in a flow injection system. Retained mercury species are then eluted with hydrochloric acid solution (3 mol/l) and subjected to phenylation before determination by gas chromatography-microwave induced plasma-atomic emission spectrometry. Limits of detection for mercury species are 10 ng l(-1) for methyl- and ethyl-mercury and 16 ng l(-1) for inorganic mercury based on processing 200 mi of sample. Application of the methodology to waters of the Manchester Ship Canal revealed elevated levels of methylmercury and inorganic mercury.