Simultaneous Multi-Element Electrothermal Atomic Absorption Determination Using a Low Resolution CCD Spectrometer and Continuum Light Source: The Concept and Methodology

Abstract

A low resolution CCD spectrometer with continuum light source and fast-heated graphite tube atomizer was employed for simultaneous multi element determination by electrothermal atomic absorption spectrometry (SMET AAS). The sample vaporization pulse was monitored by fast scanning of vapour spectra within the 190–410 nm wavelength range; absorption was measured at the CCD pixels corresponding to atomic resonance lines; function absorbance vs. concentration of atomic vapour was automatically linearized, and the modified signals integrated. The setup consisted of a D₂ or Xe arc lamp, a spectral instrument with a half-width of transmittance profile 120 pm, a linear CCD array attached to a PC and a tube atomizer furnished with a carbon fibre collector. In the experiments simultaneous determination of 18 elements was performed in the mixed solutions at the mg L^–1 to μg L^–1 level, within 4–4.5 orders of magnitude linear concentration range. About 1–2 min was needed for the measurement and calculation. Limits of detection (LOD) for individual elements were 1.5–2 orders of magnitude higher than those in the single element ET AAS, but similar or below those in flame AAS. Further reduction of LODs and correction of possible spectral and chemical interferences are associated with optimization of the light source and atomization programme and modification of the calculation algorithm.

Keywords: Electrothermal Atomic Absorption Spectrometry, Simultaneous Multi-element Determination, CCD Spectrometer, Fast-heated Graphite Tube Atomizer