Spectrophotometric determination of chromium with xylenol orange and methylthymol blue.
A new simple and sensitive method for determining traces of chromium is described. Xylenol Orange and chromium(III) form a red complex at pH 3 on heating in boiling water for 20 min. The molar absorptivity is 19.0 x 10(3). No catalytic action of the bicarbonate ion, carbon dioxide, or chromium(II) generated by metallic zinc was observed. Methylthymol Blue is a less sensitive reagent for chromium, the molar absorptivity being 11.5 x 10(3).
Cheng
K L
KL
Department of Chemistry University of Missouri at Kansas City Kansas City, Missouri 64110 U.S.A.