Development of direct-current, atmospheric-pressure, glow discharges generated in contact with flowing electrolyte solutions for elemental analysis by optical emission spectrometry

The improvement of the analytical performance of direct current atmospheric pressure glow discharge generated in contact with the small-sized liquid cathode after the addition of non-ionic surfactants to electrolyte solutions

“…From the very beginning, developed low power direct current (dc) APGD, operated between a metallic anode and an electrolyte solution that overflowed an inlet tube or a capillary, was characterized by a very simple design of the discharge cell and low operating costs [1][2][3][4][5][6][7]. Indeed, the electric power used to sustain the discharge is relatively low, i.e., within 20-80 W, and mostly dissipated at the liquid-discharge interface to evaporate water and sputter dissolved metal ions from analyzed solutions [8][9][10][11][12]. Despite a small size and a compact geometry of the discharge, excitation phenomena occurring in its near-cathode zone result in a simple atomic emission line spectra for a quite large number of metals, less common spectral overlaps of these lines and a relatively low level of the background intensity in their vicinity [1,2,11].…”

“…Despite a small size and a compact geometry of the discharge, excitation phenomena occurring in its near-cathode zone result in a simple atomic emission line spectra for a quite large number of metals, less common spectral overlaps of these lines and a relatively low level of the background intensity in their vicinity [1,2,11]. All this makes that dc-APGD generated in contact with the liquid cathode is a very convenient excitation source for the direct analysis of sample solutions by OES on the concentration of different metals present in them at the level of major and minor components or impurities [3][4][5]7,[10][11][12][13].…”

“…Changes in the design of electrolyte solution delivery capillaries made in last several years led to the improvement of the optical thinness of the discharge and its stability [4,[10][11][12][13][16][17][18][19][20][21]. A better reproducibility of the discharge gap results in a much better analytical performance of such modified discharge systems.…”

Characterization of rapidly-prototyped, battery-operated, argon-hydrogen microplasma on a hybrid chip for elemental analysis of microsamples by portable optical emission spectrometry

“…In addition to their small dimension as a key characteristic, microplasmas can be classified in a number of ways [1][2][3][4][5][6][7][8][9][10][11]. To name but a few, according to their operating pressure (e.g., atmospheric-pressure or low-pressure); according to the type of electrical power used to sustain them [8][9][10][11]; as gas-liquid microplasmas (e.g., those that use an electrolyte solution as part of an electrode [12][13][14][15][16]); according to their geometric shape (e.g., planar [10], microhollow [17]); and, according to their method of fabrication (e.g., micromachined or rapidly-prototyped microplasmas on planar, postage-stamp size 2D-chips or 3D-printed microplasmas on 3D-chips [18][19][20][21][22][23][24][25]). Thus far, microplasmas of the type classified above received attention in the literature, such as, in review articles [1][2][3][4][5][6][7], in books [26,27] and in a growing list of papers describing their use in chemical analysis [7][8][9][10]…”

“…We addressed this operational difficulty by introducing dried solution residues into microplasmas using a specially designed, electrothermal vaporization microsample introduction system [18,19,28,29]. Others employed an electrolyte solution as one of the electrodes for their gas-liquid microplasmas [12][13][14][15][16].…”