Atmospheric pressure capacitively coupled plasma atomizer for atomic absorption and source for atomic emission spectroscopy

摘要

A novel atmospheric pressure capacitively coupled ratio frequency plasma discharge method and apparatus. The apparatus is suitable for atomic absorption and atomic emission analysis of discrete sample volumes (1-50 mu l). The plasma can be operated at very low Radio Frequency (RF) input powers (10-600 W) which allow for optimal conditions for atom resonance line absorption measurements. Sample vaporization for analysis in the plasma is done by an electrically heated tantalum strip vaporizer. The vaporization and dissociation-atomization steps are separately controlled. Analyte absorption takes place in the plasma discharge which is characterized by a long path length (10-50 cm) and low support gas flow rate (0.05 to 6 L/m) both of which provide for a relatively long residence time. The device exhibits linear calibration plots and provides sensitivities in the range of from 3.5-40 pg.