Differential pulse anodic voltammetric determination of lithium ions in pharmaceutical formulations using a carbon paste electrode modified with spinel-type manganese oxide

Abstract

The use of the differential pulse voltammetry for the determination of lithium ions in pharmaceutical samples using a carbon paste electrode modified with spinel-type manganese oxide has been examined. The best voltammetric response was reached for a modified electrode in borate buffer solution of pH 9.0 and submitted to a scan rate of 5 mV s −1 and a pulse amplitude of 50 mV. This electroanalytical procedure was able to determine lithium ions in the concentration range of 8.0×10 −5–1.0×10 −2 mol l −1 even in the presence of several alkali metals (1.0×10 −3 mol l −1) with a detection limit of 7.1×10 −7 mol l −1. Rapidity, precise and good selectivity were also found for the determination of lithium ions in pharmaceutical formulations.