【摘要】 提出了在酸性条件下,以磷钼蓝反应为基础的薄层树脂相吸光光度法测定钼。此方法灵敏度较高(ε705=8.1×104L·mol-1·cm-1),比液相光度法提高10倍,精密度理想(钼浓度为20μg/25ml,n=6),RSD为2.8%。应用此法测定天然水中钼,线性范围为0～18μg·ml-1,回收率为97%～102%。更多还原

【Abstract】 0.5g of phosphate-form anion exchange resin is added to 25ml of test solution containing an appropriate amount of Mo（Ⅵ） and having an acidity of 0.2mol·L^-1 of HCl, that is 2.5ml of 2mol·L^-1 HCl in 25ml of solution. After mixing for 20min with a magnetic stirrer, heteropoly acid is formed between Mo（Ⅵ） ion and phosphate ion on the resin, which is further reduced to "molybdenum blue" with a reducing solution containing ascorbic acid, sodium potassium tartrate and sulfuric acid. The absorbance of the resin adsorbed with the "molybdenum blue" is then measured at 705nm ( λ _max of molybdenum blue) against resin blank prepared in the same way but containing no molybdenum（Ⅵ）. The resin-phase photometric method gives a molar absorptivity of ( ε ₇₀₅) 8.1×10⁴L·mol^-1·cm^-1, which is about 10 times higher than that in water phase [ ε ₇₀₅ （in H₂O solń）=7.8×10³L·mol^-1·cm^-1]. RSD （ n =6） tested at the concentration level of 20μg per 25ml achieve to a value of 2.8%. Recoveries obtained are in the range of 97%～102%.更多还原