PERFORMANCE OF A PALLADIUM FILM ELECTRODE FOR THE DETERMINATION OF THALLIUM AND LEAD IN NATURAL WATER SAMPLE BY DIFFERENTIAL PULSE ANODIC STRIPPING VOLTAMMETRY

The use of a palladium film electrode (PdFE) as an alternative electrode for the determination of thallium (Tl+) and lead (Pb2+) in water samples by anodic stripping voltammetry is proposed. Preliminary studies of the influence of the substrate were performed on the electrochemical behavior of PdFE prepared ex situ. Using a silver solid amalgam electrode as substrate (AgSAE), the effect of several parameters such as potential and deposition time, composition and pH of supporting electrolyte on the analytical response of PdFE for Tl+ by differential pulse anodic stripping voltammetry (DPASV) was initially investigated. Under best experimental conditions of deposition potential of −1.2 V and deposition time of 300s the analytical curve was linear in the Tl+ concentration from 3.0 to 100.0 µg L−1 with a relative standard deviation (RSD) <2.0%. The limit of detection (LOD) and limit of quantification (LOQ) were 0.89 µg L−1 and 2.96 µg L−1, respectively. The PdFE was successfully applied for the determination of Tl+ in water samples. Moreover, this electrode showed promising as a sensor for the simultaneous determination of Tl+ and Pb2+ and as a suitable alternative to the mercury electrode.

本研究提出采用钯膜电极（palladium film electrode, PdFE）作为替代电极，用于通过阳极溶出伏安法（anodic stripping voltammetry）测定水样中的铊（thallium, Tl+）与铅（lead, Pb2+）。针对非原位制备的PdFE的电化学行为，初步开展了基底影响的相关研究。以固体银汞齐电极（silver solid amalgam electrode, AgSAE）作为基底时，本研究首先探究了电位、沉积时间、支持电解质组成与pH等多项参数对PdFE采用差分脉冲阳极溶出伏安法（differential pulse anodic stripping voltammetry, DPASV）检测Tl+时的分析响应的影响。在沉积电位为-1.2 V、沉积时间300 s的最优实验条件下，Tl+浓度在3.0~100.0 µg L−1范围内时，分析曲线呈良好线性关系，相对标准偏差（relative standard deviation, RSD）小于2.0%。该方法的检出限（limit of detection, LOD）与定量限（limit of quantification, LOQ）分别为0.89 µg L−1和2.96 µg L−1。PdFE已成功应用于水样中Tl+的定量测定。此外，该电极作为可同时测定Tl+与Pb2+的传感器展现出良好应用前景，同时也可作为汞电极的合适替代方案。