Some analytical characteristics of a three electrode d.c. argon plasma source for optical emission spectrometry

An investigation of a commercially available three electrode d.c. plasma source burning in an inverted Y configuration was carried out. It is shown that (i) for atoms the position of maximum line intensity in the plasma is determined by the norm temperature of the spectral line, (ii) the source is stable over long periods of time, (iii) high concentrations of alkali metals in the sample can disturb the plasma resulting in an enhancement of both atomic and ionic spectral lines, (iv) detection limits are generally less than one order of magnitude higher than those obtained with an inductively coupled plasma (ICP), and (v) precision of analysis is better than 2% expressed as relative standard deviation.