Two fractions of both fulvic acids (FA) and humic acid (HA) were prepared by fractionation method of Pierce and Felbeck5 involving acid hydrolysis of soil rests. This step increases recovery of both FA and HA considerably what suggest us need for slight modification of IHSS method in some cases. The weight loss, change in organic carbon content and visible spectra are figures of merit discussed. After detailed characterization these humic substances (HS) will serve as the working standards for study of interactions between organomercurials and organic part of soil.
Authors:M. Hutta, M. Moskál'ová, M. Žemberyová, and M. Foltin
Performance of commercial Trace Mercury Analyser (TMA) originally devoted to total mercury content analyses in solid and liquid samples was tested in off-line combination with HPLC technique for speciation purposes. RPHPLC system optimized for baseline separation of mercury(II), methylmercury and phenylmercury rendered fractions with volumes directly acceptable by TMA. The main problems of this combination via off-line interfacing i.e. volatility of organomercurials and lost of fractions due to overflow from porous nickel and/or platinum transfer boats were solved by addition of wetting agent (cetyltrimethylammonium bromide) and stabilizing agent (dithizone) into the vessels prior to fractions collection. Calibration curves were measured for Hg(II) and methylmercury within range from 25 ppb to 500 ppb and were linear with correlation coefficients better than 0.9997. Detection limits achieved were around 0.3 ng for both mercury species. No matrix effects were observed during analyses of tap and surface water samples spiked at low ppb levels.
Authors:M. Foltin, S. Megová, T. Prochácková, and M. Štekláč
The chromatographic behaviour of Hg(II), methylmercury, phenylmercury and Cu(II) on three different sorbents, strong acidic sulfobutyl cation-exchanger, weak basic aminopropyl anion-exchanger and silicagel has been studied. A dithizone solution in cetyltrimethylammonium hydrogensulfate water micellar medium was found as a useful post-column derivatization reagent for UV-VIS detection. The detection limits 1.1 ng, 2.2 ng, 6.2 ng and 1.6 ng were found in silicagel chromatographic system and dithizone detection system for Hg(II), methylmercury, phenylmercury and respectively for Cu(II).