The heterometric microdetermination of mercury of mercaptobenzthiazole

The heterometric determinations of murcury or mercaptobentlnazole are very sensitive reactions. An aqueous or a dilute alcoholic solution is used and the titration may lie carried out at pH 2–10. If meicaptobenzlhiazole is determined, two analytical end-points are obtained : the first gives an estimate, the second gives the precise end-point. In all cases, the insoluble Hg(MBT)₂ is obtained, The presence of larger amounts of strong acids is disadvantageous Large amounts of acetic acid cause distuibances in aqueous solution; dilute alcoholic .solution is therefore used The theoretical end-point is obtained by the intersection of two lines. In acid solution a horizontal maximum density line is obtained at the end ot the reaction, in alkahne solution a maximum point is obtained instead. 1–2 mg mercury or meicaptobenzthiazole may be determined in 20–30 ml solution with an error of 0–3% 'Ihe titration time is 10–20 mniutes