Combination of PbFE as an electrochemical sensor and cupferron as a complexing agent for the rapid determination of Mo(VI)

Abstract

AbstractAn analytical procedure regarding the trace determination of molybdenum in natural water samples by adsorptive stripping voltammetry (AdSV) using the in situ plated lead film electrode (PbFE) was described. The method is based on adsorptive accumulation of the Mo(VI)-cupferron complex at the PbFE surface. The optimum analytical conditions include the supporting electrolyte containing 0.2-mol L−1 acetic buffer pH = 5.3, 1.45 × 10−4-mol L−1 Pb(II), and 2.0 × 10−4-mol L−1cupferron. A linear response of Mo(VI) in the concentration range of 3.0 × 10−8 to 1.0 × 10−6 mol L−1 (r = 0.997) was obtained with detection limit of 9.0 × 10−9 mol L−1 using accumulation time of 50 s. The selectivity of the method was determined by investigating how the presence of foreign ions affects the determination of molybdenum. The interferences of surface-active substances and humic substances on the molybdenum voltammetric signal were precisely examined and effectively minimized by preliminary mixing with Amberlite XAD-7 resin. The application of the proposed procedure to the analysis of natural water samples was validated by the determination of molybdenum in certificate reference materials SPS-SW1 surface water, Bystrzyca river, tap, and mineral water.