An atmospheric pressure glow discharge optical emission source for the direct sampling of liquid media

Characteristics of Atmospheric Pressure Air Glow Discharge with Aqueous Electrolyte Cathode

“…As shown in Fig 2, the most intensive bands in emission spectrum are the bands of the N 2 second positive system (C 3 u →B 3 g transition). The OH band (A 2 →X 2 , 0-0) normally used for the temperature measurements (11) is also present, but the use of this band is not convenient. First, the OH band intensity is noticeably lower than the intensity of the N 2 bands.…”

“…Unfortunately, systematic experimental data on the gas temperature as well as on the gas phase composition are absent. Only one reference (11) reported the values of 4550-4275 K extracted from the OH band intensity for N 2 as the plasma forming gas. Thus, the main goal of this study is to obtain the systematic experimental data on the gas temperature, composition of exited species in the gas phase and electric field strength for the plasma-electrolyte system.…”

Spectrochemical Analysis by Using Discharge Devices with Solution Electrodes

“…For example, magnesium and mercury detection limits are only ∼20% different with the LS-APGD device, whereas the same elements differ by >3 orders of magnitude with the miniature SCGD. 25,29 The sampling mechanism in the LS-APGD apparatus is most likely somewhat different from that of the systems discussed earlier. In the ELCAD system, there is an element-dependent vaporization efficiency, 31 whereas in the LS-APGD system, the entire solution is vaporized.…”

“…Injection-to-injection variations of <10% RSD are reported for concentrations in the hundreds of parts per million. 29,30 Concentration detection limits of 1-2 ppm and mass detection limits of 5-10 ng have been obtained for several metals. For example, magnesium and mercury detection limits are only ∼20% different with the LS-APGD device, whereas the same elements differ by >3 orders of magnitude with the miniature SCGD.…”

“…At the low end of this range, a sheath gas streaming concentrically around the cathode is used to reduce solution flow fluctuations; discrete injections are used to avoid electrode contamination. 29 The LS-APGD device is intended to be a chromatographic detector, so such injections (typically 5 µL) are appropriate. Injection-to-injection variations of <10% RSD are reported for concentrations in the hundreds of parts per million.…”