title: Mixed micellar medium for the spectrophotometric determination of molybdenum in molybdenum/tungsten mixtures.
abstract: Effects of cetyltrimethylammonium bromide (CTAB) and/or nonylphenoxypolyethoxyethanol (OP) on the absorption spectra of the complexes of molybdenum and tungsten with bromopyrogallol red (BPR) were studied. Based on these effects, a mixture of CTAB and OP was thus selected as a medium for the selective and sensitive determination of Mo in Mo/W binary mixtures. Under the optimum conditions, Beer's law was obeyed over the range 0.06-0.8 mug ml(-1) Mo with molar absorptivity being 1.3x10(5) l mol(-1) cm(-1) and detection limit 0.025 mug ml(-1). For 1.0 mug Mo, at least 20 mug W did not interfere in the determination of Mo with average recovery and relative standard deviation being 99.5% and <2%, respectively. The method developed maintained the features of simplicity and rapidity and, moreover, its selectivity and sensitivity enhanced greatly due to the use of CTAB/OP mixed micellar medium. When coupled with a compatible concentration method, the proposed method could be used for the determination of trace Mo in natural waters.
authors.affiliation: Department of Chemistry, Shandong University, Jinan 250100, People's Republic of China.
authors.forename: X
authors.initials: X
authors.lastname: Huang
authors.forename: W
authors.initials: W
authors.lastname: Zhang
authors.forename: G
authors.initials: G
authors.lastname: Xu
authors.forename: S
authors.initials: S
authors.lastname: Han
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.forename: C
authors.initials: C
authors.lastname: Li