Abdel-Halim Said H, Hassanin Hanaa A, El-Shahat Mohamed F
Chemistry Dept., Faculty of Science, Ain Shams University, Cairo, Egypt.
Ann Chim. 2003 May-Jun;93(5-6):607-14.
Accurate determination of vanadium (V) in industrial waste water is of great importance in environmental, biological and toxicological studies. Most of kinetic spectrophotometric methods based on the catalytic effect of vanadium (V), when applied to real samples for determination of trace levels of vanadium (V) lack the satisfactory sensitivity and selectivity. This may be attributed to the serious interferences of various anions which are common pollutants in industrial waste water. The oxidation of gallic acid by ammonium persulphate, catalysed by vanadium (V) was chosen for our study. The effect of the serious interferences of various anions such as chloride, bromate, bromide, chromate, iodide, iodate, molybdate, carbonate and sulphate on the net absorbance given by 4 microg l(-1) of vanadium (V) solution were studied. The minimum concentrations of citric acid, EDTA, ascorbic acid and oxalic acid as leveling off agents required to level off interfering effects due to the aforementioned anions in the kinetic determination of vanadium (V) were 50, 70, 80 and 120 microg ml(-1), respectively. In the presence of optimum concentrations of effective leveling off agents, the dynamic range can be extended and sensitivity increased as compared with the proposed method without levelling off agents. The proposed method is a rapid, sensitive and selective method for the determination of ultra trace amounts of vanadium (V) in real samples with satisfactory results.
准确测定工业废水中的钒（V）在环境、生物和毒理学研究中具有重要意义。大多数基于钒（V）催化作用的动力学分光光度法，应用于实际样品中痕量钒（V）的测定时，缺乏令人满意的灵敏度和选择性。这可能归因于工业废水中常见污染物各种阴离子的严重干扰。我们选择了在钒（V）催化下过硫酸铵氧化没食子酸的反应进行研究。研究了氯离子、溴酸根、溴离子、铬酸根、碘离子、碘酸根、钼酸根、碳酸根和硫酸根等各种阴离子对4 μg l⁻¹钒（V）溶液净吸光度的严重干扰影响。在动力学测定钒（V）中，作为消除上述阴离子干扰影响所需的柠檬酸、乙二胺四乙酸、抗坏血酸和草酸等均化剂的最低浓度分别为50、70、80和120 μg ml⁻¹。在有效均化剂的最佳浓度存在下，与未使用均化剂的方法相比，动态范围可以扩大，灵敏度可以提高。该方法是一种快速、灵敏且选择性好的方法，用于测定实际样品中超痕量的钒（V），结果令人满意。
