ANALYSES OF ORGANIC AND INORGANIC MERCURY BY ATOMIC FLUORESCENCE SPECTROMETRY USING A SEMIAUTOMATIC ANALYTICAL SYSTEM

The present work describes an improved method for the determination of total and organic mercury by decreasing analysis time (use of a dual circuit), sample size, and handling procedures and eliminating the need for a clean room condition while maintaining the detection limit below the parts per trillion (pptr) level. Total mercury was analyzed after reduction by a one-stage gold amalgamation before transfer to an atomic fluorescence spectrometer. The detection limit was 0.07 ng L(-1) for aqueous samples and 1 ng g(-1) for biological tissue. Analysis time was 5 min. Organic mercury was first derivatized using sodium tetraethylborate and then trapped onto a graphitized carbon trap before transfer to an isothermally controlled GC column coupled to a cold vapor atomic fluorescence spectrometer. The detection limit for methylmercury was 0.05 ng L(-1) for aqueous samples and 1.4 ng g(-1) for biological tissue. Samples were analyzed in 10 min. The outlined analytical protocol permits a semiautomation of both inorganic and organic mercury analyses.