190 Our systematic study in the area of carbofunctional organosilicon monomers and ion exchange and com plexing sorbents derived from them [1, 2] revealed compounds showing metallochromic properties. Such compounds are organosilicon derivatives of dithiocar bamic acid, biguanidine, and iminoguanidine [3], which are not only new organosilicon ionites and complexones but also of interest as test systems of new generation. Test methods developed on the basis of the test systems assume ever greater importance from year to year as express methods demanding no complex instrumentation for detection of elements and their semiquantitative and sometimes quantitative determi nation [4]. The general approach of all chemical test methods consists most frequently in the use of analyt ical reactions and reagents that ensure a visual effect (coloration of different intensity). In continuation of our studies, thiuram disulfide derivatives already used as chromogenic reagents attracted our attention. In particular, tetraethylthi uram disulfide is not only an efficient anti alcohol medicine (Antabuse) but is also used in analytical practice due to formation of colored complexes with a number of elements [5, 6]. For example, it forms with Cu(II) a yellow brown chelate complex known as Mercupral and used as a reagent for determination of silver and mercury [7].