Nan Z, Ren-Qing Y, Xu-Zhang Y, Zhi-Ren L
Shanghai Research Institute of Materials, Shanghai, People's Republic of China.
Talanta. 1989 Jul;36(7):733-7. doi: 10.1016/0039-9140(89)80141-9.
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%.
半二甲酚橙与铋（III）形成2:1的螯合物，其条件形成常数的对数值为3.08，摩尔吸光系数为4.2×10⁴ l·mol⁻¹·cm⁻¹。在540nm波长下，10 - 30μg的Bi（III）符合比尔定律，标准偏差为1.1μg（n = 18）。乳酸用作辅助络合剂以防止聚合和氧化。通过使用硫脲、抗坏血酸和氨基硫脲掩蔽Cu（II）以及用氯化钠“后掩蔽”Bi（III），可以消除高达1.3mg铜的干扰。所提出的方法已成功应用于直接测定铅金属中0.002%的铋，变异系数在3.7%至6.9%之间。
