A new chromium-reducible sulfur (CRS) method suitable for the quantification of reduced inorganic S (RIS) in acid-sulfate soils is presented. The new method utilises the reduction of RIS by an acidic Cr(II) solution within a sealed reaction chamber and diffusion of the produced H2S(g) into an alkaline Zn solution. It offers rapid sample processing times, without the need for large volumes of high-purity N2(g) or for specialized, expensive glassware. Examination of pyrite-talc mixtures containing up to 11.8% pyrite, revealed that the method achieves 95–98% recovery of RIS. A comparison between CRS measured by the new diffusion-based method and that measured by a standard purge-and-trap method for 25 pyritic soil samples shows a very strong (r2 = 0.996) linear relationship with a slope of 0.995. The ability of the new diffusion-based CRS method to achieve accurate and precise quantification of RIS in acid-sulfate soils is demonstrated.
Burton, ED, Sullivan, LA, Bush, RT, Johnston, SG & Keene, AF 2008, ‘A simple and inexpensive chromium-reducible sulfur method for acidsulfate soils’, Applied Geochemistry, vol. 23, no. 9, pp. 2759-2766.
Publisher's version of article available at http://dx.doi.org/10.1016/j.apgeochem.2008.07.007