Spectrophotometric determination of molybdenum in vegetal tissues, soils and pharmaceutical compounds with mandelohydroxamic acid
Abstract
Molybdenum was determined spectrophotometrically as an ion associate, formed between the anionic complex [MoVIO2(MHA)Cl2]–(MHA = mandelohydroxamic acid) and the methyltrioctylammonium (MTOA) cation, extracted into toluene. The absorbance of the yellow toluene solution was measured at 375 nm. The apparent molar absorptivity is 1.62 × 104 l mol–1 cm–1. For the determination of 2.5 p.p.m. of MoVI the relative error is 0.5%. The detection limit is 0.05 µg ml–1 of MoVI. The extraction of the mixed ligand complex, MoO2(MHA)Cl2(MTOA) is discussed. The proposed method was applied to the determination of Mo in vegetal tissues, soils and pharmaceutical compounds.