Separation and Spectrophotometric Determination of Trace Molybdenum(VI) with 5-Octyloxymethyl-8-quinolinol in Large Amounts of Diverse Ions

Abstract

Molybdenum(VI) can be completely extracted with 2.0×10^-2mol dm^-3 5-octyloxymethyl-8-quinolinol (HO₈Q) into chloroform from 3.0mol dm^-3 nitric acid solution to give a yellowish complex absorbing at 380nm with the molar extinction coefficient of 1.14×10⁴mol^-1 dm³ cm^-1. The extracted molybdenum(VI)-HO₈Q complex is formulated as MoO₂(O₈Q)₂. A 5-octyloxymethyl-8-quinolinol was able to simply and selectively separate and spectrophotometrically determine molybdenum(VI) in the presence of large amounts of such metal ions as iron(III), nickel(II), cobalt(II), zinc(II), cadmium(II), lead(II), niobium(IV), gallium(III), thallium(I) and copper(II). These ions did not interfere with the determination of molybdenum(VI) with HO₈Q. The present method was satisfactorily applied to the spectrophotometric determination of molybdenum in an NBS standard steel sample. The extraction behavior of molybdenum(V) with HO₈Q was also described.