A Fast and Simple Voltammetric Method Using a Lead Film Electrode for Determination of Ultra-Trace Concentration of Titanium in Environmental Water Samples

Abstract

A fast, simple and highly sensitive adsorptive stripping voltammetric procedure for determination of trace quantity of Ti(IV) in natural water samples containing high concentrations of surfactants and humic substances was developed. The procedure was based on simultaneous lead film formation and adsorptive accumulation of the Ti(IV)-cupferron complex onto the in situ plated lead film electrode. Measurement conditions such as the concentration of cupferron, pH of the supporting electrolyte, conditions of lead film formation, accumulation potential and time were optimized. The interferences from dissolved surfactants and biosurfactant were eliminated by adding Amberlite XAD-7 resin to the voltammetric cell. Under optimum conditions the linear calibration plot for Ti(IV) was obtained in the range from 5.0 × 10−9 mol L−1 to 1.5 × 10−7 mol L−1 for the accumulation time of 60 s. The detection limit for the accumulation time of 60 s was about 1.7 × 10−9 mol L−1. The calibration graph obeyed the equation y = 0.487x + 0.843, where y and x were the peak current (μA) and Ti(IV) concentration (nmol L−1), respectively. The linear correlation coefficient was r = 0.996. The proposed method was successfully applied to determine titanium in the matrix-rich water sample and was validated in the course of Ti(IV) recovery determination from spiked natural water samples.