title: Synthesis and analytical applications of 2,4-dinitro-6-chlorophenylazothymol.
abstract: The newly synthesized 2,4-dinitro-6-chlorophenylazothymol, a weak acid with pK(a) 8.33 +/- 0.04 at 27 degrees, is proposed as a sensitive spot reagent for magnesium, with an identification limit of 0.14 microg at pH 10.5-11.6. Silver and manganese(II) interfere but can be masked by means of cyanide and periodate respectively. There is little interference by anions. The reagent also serves as an acid-base indicator with a transition interval of pH 7-9, giving a sharp colour change at the equivalence point.
authors.affiliation: Geological Survey of India, Rajasthan Circle, Jaipur, India.
authors.forename: S K
authors.initials: SK
authors.lastname: Mukerji
authors.forename: H L
authors.initials: HL
authors.lastname: Sharma