浊点萃取-石墨炉原子吸收光谱法测定痕量钯

Determination of trace amounts of palladium by graphite furnace atomic absorption spectrometry after cloud point extraction

建立了浊点萃取-石墨炉原子吸收光谱法(GFAAS)测定痕量金属钯的新方法,利用表面活性剂Triton X-114和络合剂2-(5-溴-2-吡啶偶氮)-5-二甲氨基苯胺(5-Br-PADMA)对钯进行浊点萃取。研究了溶液pH、试剂浓度、平衡温度和加热时间等因素对浊点萃取及测定灵敏度的影响。优化条件为:pH 5.50 HAc-NaAc缓冲,0.08 mL 5×10-4 mol/L 5-Br-PADMA,0.70 mL10g/L Triton X-114。在最佳条件下,方法的线性范围为0.1～10 ng/mL,钯的检出限为0.068 ng/mL,富集倍率为45倍。该方法可用于环境样品中痕量钯的富集和测定,结果令人满意。

A new cloud point extraction （CPE） separation of trace level of palladium as a prior step to its determination by graphite furnace atomic absorption spectrometry （GFAAS） has been developed. The CPE method was based on employing Triton X-114 as a surfactant and 2-（ 5-Bromo-2-pyridylazo ）-5-dimethylamino- amino-benzen （5-Br-PADMA） as a complexing reagent. The chemical variables affecting CPE were evaluated such as pH, concentration of reagent, equilibrium temperature and developing time. The optimum chemical conditions were pH 5.50 HAc-NaAc, 0. 08 mL of 5×10^-4 mol/L 5-Br-PADMA, 0. 70 mL of 10 g/L Triton X - 114. Under the optimum conditions, the linear ranger was 0. 1 -10 ng/mL, and the limit of detection was 0. 068 ng/mL for palladium with the enhancement factor of 45. The proposed method was applied to the determination of palladium in environmental samples with satisfactory result.