Photochemical reduction of thallium(III) with hydrogen peroxide.

A convenient method for determination of thallium(III) is based on photochemical reduction with hydrogen peroxide in the presence of bromide as catalyst, followed by oxidation of thallium(I) with potassium bromate.

Spectrophotometric determination of some antiamoebic and anthelmintic drugs with metol and chromium(VI).

A sensitive spectrophotometric method is reported for the determination of tinidazole (TZ), metronidazole (MZ), benzoyl metronidazole (BMZ) or niclosamide (NS) either in pure form or in formulations. This method is based on reduction with zinc dust and hydrochloric acid followed by reaction with metol and potassium dichromate at pH 3.0 +/- 0.2 to give a coloured product having maximum absorbance at 720 nm (for TZ, MZ and BMZ) or 530 nm (for NS).