Determination of iodide by detection of iodine using gas-diffusion flow injection and chemiluminescence

Abstract

This work describes development of a flow injection (FI) system for determination of iodide, based on the chemiluminescence (CL) reaction between iodine and luminol. Iodide in the sample zone is oxidized to iodine. Employment of a gas-diffusion (GD) unit allows for selective detection of the generated CL (425nm). Preliminary results showed for concentrations of less than 2mgL(-1), that signals were irreproducible and that the calibration was not linear. In order to solve these problems, a method of 'membrane conditioning' was investigated, in which iodide stream was continuously merged with oxidant to generate I(2) that conditioned the GD membrane and tubing. This minimized surface interacti..