Stability of inorganic mercury and methylmercury on yeast-silica gel microcolumns: field sampling capabilities

The stability of methylmercury and inorganic mercury retained on yeast-sili ca gel microcolumns was established and compared with the stability of thes e species in solution. Yeast-silica gel columns with the retained analytes were stored for two months at three different temperatures: -20 degreesC, 4 degreesC and room temperature. At regular time intervals, both mercury spe cies were eluted and quantified by cold vapor atomic absorption spectrometr y (CVAAS). Methylmercury was found stable in the columns over the two-month period at the three different temperatures tested while the concentration of inorganic mercury decreased after one week's storage even at -20 degrees C. These results are of great interest since the use of these microcolumns allows the preconcentration and storage of mercury species until analysis, thus saving laboratory space and avoiding the problems associated with main taining species integrity in aqueous solution.