AN EXTRACTIVE SPECTROPHOTOMETRIC METHOD OF DETERMINATION OF MOLYBDENUM(VI) USING ROXY-2-(4-METHOXYPHENYL)-6-METHYL-4H-CHROMEN-4-ONE

roxy-2-(4-methoxyphenyl)-6-methyl-4H-chromen-4-one (HL) behaved as a s ensitive spectrophotometric reagent for molybdenum(VI). The metal ion formed a yellow complex with the reagent in acetic acid medium. The co mplex was extractable into 1,2-dichloroethane and the absorbance value s remained unchanged for more than one week. Spectral data showed the formation of 1:2 species with lambda(max) value at 411 nm. Beer's law was obeyed over the concentration range of 0-2.3 ppm. The molar absorp tivity and Sandell's sensitivity were calculated to be 5.61 x 10(4) dm 3 mol-1 cm-1 and 0.0017 mug Mo cm-2 respectively, at 411 nm. The effec t of as many as 41 cations and 28 anions and complexing agents was stu died. Out of these only Sn(II), Ce(IV), citrate, oxalate, disodium dih ydrogen ethylenediaminetetraacetate, and hydrogen peroxide interfered seriously. For ten replicate determinations of 1 mug Mo cm-3 the stand ard deviation was 0.008 with a relative mean error of +/-0.09%. The me thod is simple, selective, precise and rapid. It has been applied sati sfactorily to the determination of molybdenum in steels, waters and fl ue dust samples.