流动注射在线分离富集-火焰原子吸收光谱法测定钯
FAAS Determination of Palladium with FI-On-line Pre-enrichment
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摘要: 将聚氯乙烯-丁二酮肟复膜树脂作为固定相填充到自制的微型柱中,将流动注射在线分离富集与火焰原子吸收光度法联用,组成同时富集、顺序反向洗脱的环内双柱复线流路及检测系统,对废催化剂中微量钯进行测定.废催化剂样品经盐酸(5+95)溶液溶解后,过滤所得残渣溶于王水中.分析时将pH 2的试液以7.5 mL·min-1速率采样90 s,用乙二胺-20 g·L-1氢氧化钠(1+9)混合溶液作为洗脱液,从柱上将钯(Ⅱ)洗脱并引入原子吸收光谱仪的雾化器中进行测定,线性范围为1.25 mg·L-1以内,检出限(3S/N)为15 μg·L-1,应用此方法分析了地质标样及铂矿样等已知样品,测得结果与标准值或已知值相符,其相对标准偏差(n=7)均小于2.5%.Abstract: Preparation of a micro-column filled with model 717 ion-exchange resin,which was covered with a thin membrane of dimethylglyoxime dispersed in PVC,was described and used for the separation and pre-enrichment of Pd(Ⅱ).Based on a LZ-2000 FI-analyzer,manifold for enrichment of Pd(Ⅱ) on the microcolumn,elution of Pd(Ⅱ) from the column with a mixture of ethylenediamine and 20 g·L-1 NaOH solution (mixed in the ratio of 1+9 by volume),and introduction of the eluate into the atomizer of AAS instrument was designed,fabricated and its operation given in detail.Waste catalyst sample was treated with HCl (5+95) solution,and the insoluble residue was collected by filtration and dissolved in aqua regia.The solution,after adjusting its acidity to pH 2,was introduced into the FI-manifold for analysis.Rate and time of sample solution introduction were 7.5 mL·min-1 and 90 s.Linear relationship between values of absorbance and concentration of Pd(Ⅱ) was kept in the range within 1.25 mg·L-1.Detection limit (3S/N) of the method was found to be 15 μg·L-1.Precision and accuracy of the method were checked by analysis of 3 samples of geological standards and platinum ores,the results obtained were in consistency with the standard or known values,with values of RSD′s (n=7) less than 2.5%.