A miniaturized glow discharge applied for optical emission detection in aqueous analytes

DC glow discharge atomic emission spectroscopy of aqueous analytes has been performed in a planar glass microstructure at close to atmospheric pressure using argon as a carrier gas. Sample introduction was achieved using a technique in which the liquid sample itself is employed as the cathode for the glow discharge. To attain sufficient transport of the sample into the discharge region to allow for emission spectroscopy, acidification of the liquid sample is required. Results demonstrate the detection of copper in solution is possible with the observation of five atomic emission lines of copper (at 325 nm, 327 nm, 511 nm, 515 nm and 522 nm). It is hoped that this detection method could be integrated with other micro-fluidic systems as part of a mu-TAS device as well as being useful as a portable, stand-alone detector. However, stability issues will need to be resolved to allow for further optimization and characterization of the device.