Spatial imaging of the furnace atomization plasma emission spectrometry source

The spatial distribution of background species and analyte in a He FAPES source have been determined using a charge-coupled device (CCD) imaging system. Imaging of the He 667.82 nm support gas line reveals the presence of two distinct plasmas: an intense luminous zone located around the centre electrode and a diffuse plasma near the tube walls. In a graphite tube at room temperature, the plasma system exhibits a significant dependence on the d.c. bias of the centre electrode for a constant forward r.f. power of 50 W. Polyatomic background species exhibit similar overall distributions and response to changes in the centre electrode d.c. bias. The ingress of atmospheric nitrogen into the plasma can be indirectly detected at elevated tube wall temperatures. Images obtained for Ag atomized into 30 W and 50 W plasmas point out the role of the centre electrode as a primary condensation and secondary re-volatilization site. Condensation and re-evaporation is alleviated when Ag is atomized into a 70 W plasma as the result of plasma-induced heating of the centre electrode.NRC publication: Ye

Two-dimensional imaging of excited analyte species in electrothermal vaporizers

Applications of a charge-coupled device (CCD) imaging spectrometer as a detection system for the determination of two-dimensional images of transient atomization events in a furnace atomization plasma emission spectrometric (FAPES) source are reviewed. Spectrally, spatially and temporally resolved images of the emission from analyte species (Ag(I), Ca(I) and Ca(II)) and plasma support gas (He(I)) in a 50 W He rf plasma are presented and the advantages of using a CCD camera system for fundamental characterization of vaporization, atomization, and ionization processes in the FAPES source are discussed. The limitations associated with the current system \u2014 insensitivity and limited spectral resolution \u2014 are highlighted and means of overcoming them are suggested.NRC publication: Ye

Condensation of analyte vapor species in graphite furnace atomic absorption spectrometry

NRC publication: Ye