Characterization of the analytical capabilities of an atmospheric micro‐plasma device for the detection of nonmetals

A low power micro-plasma device was designed, constructed and evaluated for nonmetal detection, particularly for the direct measurement of phosphorus and sulfur. The device employed an open discharge chamber to generate an argon plasma discharge at atmospheric pressure of about 2 watts power and 150 nL volume for elemental excitation and molecular fragmentation. The emission light from the miroplasma source was collected and coupled to a palm-sized spectrometer through an optical fiber for spectral measurement. The characteristics of the low power micro-nano-plasma discharge, such as relationship of voltage–current, were studied to optimize discharge parameters. Two spectral lines of 253.6 nm and 469.4 nm were used for detection of phosphorus and sulfur, respectively. The stability of the low power micro-plasma device was quantitatively evaluated, and the analytical figures of merit for nonmetal detection were reported. The detection limits are 68 ppbv for phosphorus, and 1.0 ppmv for sulfur, respectively. The sensitivities of the device for nonmetal detection are comparable with those of conventional methods. However, our device provides significant advantages of small size, low power, low cost, and fieldable detection.