A Handheld Microdischarge Spectroscopy System for High-Speed Chemical Analysis of Gaseous and Liquid Samples

This paper presents a handheld microsystem that uses discharge spectroscopy to analyze chemicals both in vapor and liquid phases. The system employs a battery-operated circuit and interface for generating the microdischarge and performing the analysis. It uses swappable liquid and gas discharge microchips, which interface to the common platform. A pump and inert carrier gases are not utilized. The system can generate one or a series of single shot microdischarges per chemical analysis. Synchronized emission spectroscopy is used to optimize sampling. The liquid discharge microchip has an active area of 1 mm x 1 mm and a discharge gap of 50 µ m. It employs a porous cathode which for introduction of the liquid into the microplasma. This results in a reliable system that can detect 2 ppm of Cr sample without preconcentration. The gas discharge microchip uses the discharge between two metal electrodes. It has a discharge gap of 50 µ m and and an active area of 500 µ m x 500 µ m. The sensor detects 13 ppm of acetone vapor in air.