Re. Sturgeon et al., IMPACT OF BIAS VOLTAGE ON FURNACE ATOMIZATION PLASMA EMISSION-SPECTROMETRY PERFORMANCE, Spectrochimica acta, Part B: Atomic spectroscopy, 48(6-7), 1993, pp. 893-908
The effects of an applied d.c. bias potential on the analytical respon
se from a furnace atomization plasma emission spectrometry (FAPES) sou
rce operating with a 50 W He plasma were investigated. Enhancements in
absolute sensitivity and detection limits for B, Cd, Pb, Ni, Fe, S, P
t and Se ranged from 2-10-fold as compared to the usual ''free running
'' self-bias situation and response from all species was enhanced as t
he applied bias was made more negative. Reflected power increases up t
o 35 W exert little effect on the excitation conditions within the pla
sma. The excitation temperature of the He support gas as well as that
of Fe introduced as a thermometric species indicated that, while the t
emperature of the former varied by up to 700 K over the course of an a
tomization transient, that of Fe remained relatively stable. Bias cont
rol reduced the fluctuation in the He temperature to under 400 K.