丁二酮肟分光光度法测定锆及锆合金中镍

采用氢氟酸-硝酸体系溶解试样,硼酸饱和溶液中和试样溶解后体系中过量的氢氟酸,再以柠檬酸为络合剂,碘为氧化剂,丁二酮肟为显色剂,基于丁二酮肟与镍形成酒红色络合物,建立了锆及锆合金中镍含量的测定方法。重点考察了氢氟酸用量对测定的影响,结果表明,采用以下氢氟酸用量可保证试样溶解完全:当试样量不大于1.0g时,选用2.5mL氢氟酸;当试样量为2.0g时,选用5.0mL氢氟酸。对实验条件进行优化,结果表明,在优化的实验条件下,镍的质量分数在0.002%~0.15%范围内与其吸光度呈线性关系,相关系数为0.9999,方法的检出限为0.01μg/mL,测定下限为0.04μg/mL。考察了锆基体与共存元素对镍测定的影响,结果表明:锆基体与共存元素对镍的测定无影响。按照实验方法测定锆合金标准样品和4种锆及锆合金合成试样中镍,测定结果与电感耦合等离子体原子发射光谱法(ICP-AES)基本一致,且锆合金标准样品测定结果与认定值一致,所测结果的相对标准偏差(RSD,n=11)为2.9%~10.5%。

Determination of nickel in zirconium and zirconium alloy by dimethylglyoxime spectrophotometry

The sample was dissolved in hydrofluoric acid-nitric acid system. Excessive hydrofluoric acid in sample solution was neutralized with saturated boric acid solution. Based on the coloring reaction that dimethylglyoxim could react with nickel to form wine red complex, a determination method of nickel in zirconium and zirconium alloy was established with citric acid as complexing agent, iodine as oxidizing agent, and dimethylglyoxime as coloring agent. The effect of hydrofluoric acid dosage on the determination was emphatically investigated. The results showed that the following amount of hydrofluoric acid could ensure the complete dissolution of sample: 2.5mL of hydrofluoric acid was used when the sample mass was less than 1.0 g, and 5.0mL of hydrofluoric acid was used when the sample mass was 2.0g. The experimental conditions were optimized. Under the optimal experimental conditions, the mass fraction of nickel in range of 0.002%-0.15% was linear to its corresponding absorbance with the correlation coefficient of 0.9999. The detection limit of this method was 0.01μg/mL and the low limit of determination was 0.04μg/mL. The effect of zirconium matrix and coexisting elements on the determination of nickel was investigated. The results showed that the zirconium matrix and coexisting elements had no influence on the determination of nickel. The content of nickel in zirconium alloy certified reference material and four synthetic samples of zirconium and zirconium alloy were determined according to the experimental method. The results were basically consistent with those obtained by inductively coupled plasma atomic emission spectrometry (ICP-AES). The results of zirconium alloy certified reference material were consistent with the certified values. The relative standard deviation (RSD, n=11) of determination results were between 2.9% and 10.5%.