Piezoelectrically Induced Selective Flame Signal Modulation

Abstract

The design and performance of two devices for selective spectral modulation in flame emission and atomic absorption spectrometry are reported. The similar techniques use periodic piezoelectrically induced deformation of one or two fluidic channels to the solution nebulizer. The mechanically simpler channel device generates a regular ac ripple on the solution flow into the flame. In certain situations, the influence of the solvent pulsing on the flame temperature permits the differentiation of flame background signals from signals of analytical interest; alternatively, advantage can be taken of mutually compensating flame processes which negate the influence of solvent modulation on the flame background. In the generally applicable dual channel technique, the nominal solution uptake rate is constant and the ac components in the flame spectra represent the differences in chemical composition between the analytical and the blank solutions. Effective background discrimination ratios for certain band systems exceed 103:1.