The in-situ excitation on internal electrode of DBD-OES system for cadmium sensitive detection

Abstract

The utilization of microplasma excitation sources in miniature systems offers reliable tools for the portable detection of heavy metal contamination. Dielectric barrier discharge (DBD)-based optical emission spectrometry has emerged as a significant technique for the detection of metal ions recently. Here, a sensitive miniature DBD-OES system for cadmium enrichment and detection is developed. A piece of ceramic tube with abundant hydroxyl (-OH) and alumina (AlO) functional groups is used for cadmium pre-concentration and serve as a part of the internal electrode of the DBD. When microplasma generates, the cadmium on the surface of the internal electrodes is desorbed and in-situ excited, and the characteristic emission line of cadmium appears. The mechanism of cadmium excitation on ceramic tube, the characteristics of the microplasma excitation and the enrichment on the internal electrode are discussed. Under the working conditions, the emission intensity of cadmium shows linear relationship within the range of 0.5–8 μg L−1, and the limit of detection (LOD) is 0.3 μg L−1. Finally, a series of water samples are determined to validate the applicability of the present system.