A low-cost non instrumental method for semiquantitative determination of mercury in fish

A non instrumental method for the semiquantitative determination of mercury in fish is described. The sample is acid digested and the mercury vapor re leased after chemical reduction with SnCl2. The mercury vapor is then colle cted on a detecting paper covered with an emulsion of Cu2I2, 3% carboxymeth ylcellulose and MgCl2 as moistener agent. The colored Cu-2[HgI4] complex is formed and the color intensity is proportional to the mercury concentratio n in the original sample. Parameters such as sample mass/digestion solution volume ratio, emulsion composition, paper covering technique, carrier gas flow were investigated. Comparative studies using CVAAS and digital color a nalysis after scanning the papers confirmed the applicability of the method to real samples.