3-Hydroxy-2-Methyl-1,4-Naphthoquinone Monoxime : A New Sensitive Reagent for the Determination of lron(II) and Cobalt(II)

Department of Chemistry, University of Delhi, Delhi-110 007

Manuscript received 23 April 1981, revised 8 July 1982, accepted 28 January 1983

3-Hydroxy-2-methyl-1,4-naphthoquinone monoxime is suggested for the estimation of 21.5-114.0 µg iron(Il) and 3.5-41.5 µg cobalt(II) over the pH range 4.8-7.0 and 5.0-7.5, respectively. The iron(ll) and cobalt(ll) complexes possess maximum absorption at 460 nm and 430 nm, respectively with the molar absorptivlties of 1.28 x 10⁴ and 3.24 x 10⁴ I.cm^-1. mole^-1. The determinations have been carried out in 50% ethanol. The limits of tolerance of foreign ions have been studied.