Trace metal determination in tears by anodic stripping voltammetry in a capillary flow injection system

Abstract

The adaptation of a fused silica capillary system to flow injection is described. The incorporated electrochemical cell, consisting of a microelectrode arrangement, is demonstrated to be well suited for conductivity and voltammetric measurements. Microanalytical studies with injection volumes within the nanolitre range were performed. Analytical characteristics of the method, such as accuracy, precision, sensitivity and limit of detection, are discussed. By using capillary flow injection, tear samples were investigated with respect to conductivity and trace-metal concentration. The last was performed via anodic stripping voltammetry at mercury-coated platinum microdisc electrodes. Lead, cadmium and copper were found to be present at concentrations in the lower µg l^–1 range.