Preliminary investigations of a helium alternating current plasma for the determination of metals by atomic emission spectrometry

The construction and operation of an alternating current plasma are described. The plasma is generated across two copper electrodes utilizing helium as the plasma and nebulizer gas. The plasma operates at a frequency of 60 Hz. Aqueous solutions containing elements of interest are introduced into the plasma by two different devices: a glass frit nebulizer and a thermospray interface. Improved detection limits are associated with the latter. Analytical characteristics for 14 elements are reported including detection limits (3σ) for the metals investigated at the ppb level. Linear ranges of 2-4 orders of magnitude are observed. Signal precision, at the level of 10 times the detection limit, ranges from 1.9 to 10% relative standard deviation.