title: Spectrophotometric determination of bismuth with semi-xylenol orange and its application in metal analysis.
abstract: Semi-Xylenol Orange forms a 2 : 1 chelate with bismuth(III), which has a logarithmic value of 3.08 for its conditional formation constant and a molar absorptivity of 4.2 x 10(4) l.mole(-1).cm(-1). Beer's law is obeyed at 540 nm over the range 10-30 mug of Bi(III), with a standard deviation of 1.1 mug (n = 18). Lactic acid is used as an auxiliary complexing agent to prevent olation and oxolation. Interference from up to 1.3 mg of copper can be eliminated by the combined use of masking Cu(II) with thiourea, ascorbic acid and thiosemicarbazide and "post-masking" Bi(III) with sodium chloride. The proposed method has been successfully applied to the direct determination of 0.002% of Bi in lead metal, with a coefficient of variation varying from 3.7 to 6.9%.
authors.affiliation: Shanghai Research Institute of Materials, Shanghai, People's Republic of China.
authors.forename: Z
authors.initials: Z
authors.lastname: Nan
authors.forename: Y
authors.initials: Y
authors.lastname: Ren-Qing
authors.forename: Y
authors.initials: Y
authors.lastname: Xu-Zhang
authors.forename: L
authors.initials: L
authors.lastname: Zhi-Ren