Iodnitrotetrazolium chloride-A new analytical reagent for determination of chromium

The extraction of chromium (VI) with iodnitrotetrazolium chloride (INT) was studied spectrophotometrically. The basic spectrophotometric characteristics of the ion associated formed were determined. Using different methods it was found that the ratio between chromium and INT was 1:1. The molar absorptivity of the associate is (250) = (3.70 +/- 0.08) x 10(4) 1.mole(-1).cm(-1). Performing the reaction in acid medium (0.1-1.1M hydrochloric acid) allowed the determination of chromium in the presence of large amounts of W(VI), Mo(VI), Fe(III) and V(V). Hence INT is suggested as a sensitive and selective reagent for extractive-spectrophotometric determination of microquantities of chromium(VI).