A water spectroscopy microsystem with integrated discharge source, dispersion optics, and sample delivery

This paper reports a microsystem integrating the fluidic, electrical and optical elements required for field-portable water-chemistry testing by electric discharge spectroscopy. The device utilizes a DC microdischarge as a spectroscopic source. The discharge is created by applying a DC voltage between a metal anode and uses the water sample as the cathode. Impurities are sputtered from the water sample into the microdischarge. A blazed grating is used as the dispersion element, along with an aperture fabricated on a glass substrate. The microsystem is assembled and used with a CCD sensing element to distinguish atomic spectra. Two versions of the microsystem have been implemented: planar and a capillary tube-based device. Detection of Cr and other chemicals in water samples has been successfully demonstrated with both devices.