Spectrophotometric Determination of Magnesium(ll) with 2-Carboxy-2"-hydroxy-3' , 5' -dimethylazobenzene-4- sulphonic Acid

Laxminarayan, Institute of Technology, Nagpur-440 010

Chemistry Department, Nagpur University, Nagpur-440 010

Manuscript received 18 October 1982, revised 24 August 1983, accepted 25 March 1984

2-Carboxy-2'-hydroxy-3',5'-dimethylazobenzene-4-sulphonic acid (CHDMAS) is recommended as a chelating agent for the spectrophotometric determination of magnesium (II). It forms a red coloured complex with magnesium(ll) which can be quantitatively determined at pH 11.0. The complex has absorption maximum at 510 nm and it obeys Beer's law over 0.5 \(\mu\)g to 16.0 \(\mu\)g Mg(ll) per ml. The reagent forms 1 : 1 complex with Mg(ll). The method is sensitive and fast.