[Preliminary test with chlorindazone DS for zinc in Sintox residue]

A method ("pretest") for visualization of gunshot residues of Sintox-ammunition is described, resulting in a coloured and additionally in a fluorescent so called "distribution-image". The handling of the method is the same as for the detection of Sinoxid residues, where tartaric acid as transfer substance and rhodizonate as detection reagent on filter paper are used. As reagent for the specific detection of zinc, non-commercial chlorindazone DS is used, which can be synthesized in a two-step reaction from commercially available precursors. The method allows to detect Sintox-residues even after a primary test for Sinoxid-residues was carried out with sodium rhodizonate. Unfortunately zinc and its compounds are widely found in many industrial and commercial products. Since this is a certain disadvantage of the method, "good laboratory practice", careful selection of auxiliary means (zinc free gloves) and consideration of possible sources of zinc-contamination are aspects of principal importance to obtain reliable results.