Determination of Trace Tl(I) by Differential Pulse Anodic Stripping Voltammetry Using a Novel Modified Carbon Paste Electrode

In this study, novel modifiers composed of multi walled carbon nanotubes (MWCNTs) and a series of noncyclic crown-type polyethers were prepared. The ligand loaded MWCNTs along with a room temperature ionic liquid (RTIL) 1-butyl-3-methylimidazolium hexafluoro phosphate ([bmim][PF ₆ ]) were used for modification of a simple and low-cost carbon paste electrode (CPE). The modified CPE was employed for the determination of thallium(I) in aqueous medium using differential pulse anodic stripping voltammetry (DPASV) method. The effect of different experimental conditions such as supporting electrolyte, solution pH, accumulation potential, accumulation time, and modifier dosage were investigated and optimized. By DPASV, a linear dynamic range of 0.3–70 μ g l ⁻¹ was achieved. The detection limit (3S _b ) was found to be 0.08 μ g l ⁻¹ , below the maximum allowable limit (2 μ g l ⁻¹ ) of the U.S. Environmental Protection Agency (USEPA). The present assay was also showed acceptable reproducibility with a relative standard deviation (RSD) value of 3.8% at 25.0 μ g l ⁻¹ level ( n = 7). The applicability of this electrode was successfully explored by measuring of thallium(I) in some natural waters without interference from sample matrix.