An open-to-air type electrolyte cathode
discharge (ELCAD) has been developed with a new design. The
present configuration leads to a stable plasma even at low flow
rates (0.96 mL/min). Plasma fluctuations arising from the
variations in the gap between solid anode and liquid cathode
were eliminated by providing a V-groove to the liquid
glass-capillary. Cathode (ground) connection is given to the
solution at the V-groove itself. Interfaced to atomic emission
spectrometry (AES), its analytical performance is evaluated. The
optimized molarity of the solution is 0.2 M. The analytical
response curves for Ca, Cu, Cd, Pb, Hg, Fe, and Zn demonstrated
good linearity. The limit of detections of Ca, Cu, Cd, Pb, Hg,
Fe, and Zn are determined to be 17, 11, 5, 45, 15, 28, and 3 ng
mL-1. At an integration time of 0.3 s, the relative
standard deviation (RSD) values of the acid blank solutions are
found to be less than 10% for the elements Ca, Cu, Cd, Hg, Fe,
and Zn and 18% for Pb. The method is applied for the
determination of the elemental constituents in different matrix
materials such as tuna fish (IAEA-350), oyster tissue (NIST SRM
1566a), and coal fly ash (CFA SRM 1633b). The obtained results
are in good agreement with the certified values. The accuracy is
found to be between 7% and 0.6% for major to trace levels of
constituent elements and the precision between 11% and 0.6%. For
the injection of 100 μL of 200 ng mL-1 mercury
solution at the flow rate of 0.8 mL/min, the flow injection
studies resulted in the relative standard deviation (RSD) of 8%,
concentration detection limit of 10 ng/mL, and mass detection
limit of 1 ng for mercury.
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