浊点萃取-激光热透镜光谱法测定痕量钯

Determination of trace palladium by cloud point extraction coupled with thermal Lens spectrometry

以2-（5-溴-2-吡啶偶氮）-5-二甲氨基苯胺（5-Br-PADMA）为络合剂,用非离子型表面活性剂Triton X-114浊点萃取样品溶液中的痕量钯。探讨了溶液pH、络合剂用量、平衡温度及时间、表面活性剂用量等实验条件对体系浊点萃取效率及测定灵敏度的影响,并详细研究了多种阴、阳离子对测定的干扰情况。在最佳条件下,钯浓度在4～80 ng·mL^-1范围内与热透镜信号强度呈线性关系,方法的检出限为1．2 ng·mL^-1,该法用于自来水中痕量钯的测定,加标回收率为95．5～96．7%,相对标准偏差为0．87%～2．49%。

2-（5-bromo-2-pyridylazo）-5-di methylaminoaminobenzene（5-Br-PADMA） was selected as the complexing agent and oc-tylphenoxy-polyethoxyethanol（Triton X-114）was added as a nonionic surfactant. The main factors affecting the CPE efficiency such as pH, the concentrations of complexing agent and surfactant, equilibration temperature and centrifugation time were dis-cussed. Under optimum conditions,the analytical curve was linear for the concentration range of 4～80 ng·mL^-1 and the detection limit was 1. 2 ng·mL^-1 . The recovery of Pd was in the range of 95. 5～96. 7%. The relative standard deviation of 6 replicate deter-minations was 0. 87% ～2. 49%. The method was successfully applied to the extraction and determination of trace Pd in tap water.