A very simple, ultra-sensitive and highly selective non-extractive spectrophotometric method for the determination of trace amounts of molybdenum(VI) using 2-hydroxyacetophenonebenzoylhydrazone (HAPBH) has been developed. 2-hydroxyacetophenonebenzoylhydrazone reacts in acidic (0.03-1 M H2SO4) and 30% 1, 4-dioxane media with molybdenum(VI) to give a redishyellow chelate which has an absorption maxima at 443 nm. The average molar absorption coefficient and Sandell’s sensitivity were found to be 2.59×104 L mol-1 cm-1 and 15 ng cm-2 of MoVI, respectively. Linear calibration graphs were obtained for 0.1-30 mgL-1. The stoichiometric composition of the chelate is 1:2 (Mo:HAPBH). The absorbance intensity of the metal chelate reaches to a constant value within few seconds and remains unchanged for more than 48 hours. Large excess of over 60 cations, anions and complexing agents (like tartrate, oxalate, chloride, phosphate, EDTA, ascorbic acid, bromide, citrate, etc.) do not interfere in the molybdenum determination. The developed method was successfully used for assaying several standard reference materials (alloys and steels), environmental waters (inland and surface), biological samples (human blood and urine), soil samples, solutions containing both molybdenum(V) and molybdenum(VI) and complex synthetic mixtures. The method has high precision and accuracy (s = 0.01 for 0.5 mgL-1).
M. Jamaluddin Ahmed, K. Jakir Hossen, Tasnima Zannat. (2005) Simple Spectrophotometric Method for the Determination of Molybdenum in Industrial, Environmental, Biological and Soil Samples Using, 2 -Hydroxyacetophenonebenzoylhydrazone, Pakistan Journal of Analytical & Environmental Chemistry, Volume 6, Issue 2 .