Simultaneous multi-element analysis by continuum source atomic absorption spectrometry with a spatially and temporally isothermal graphite furnace

Abstract

The performances of three furnace systems were compared with respect to conditions for multi-element atomic absorption spectrometry (AAS), interference effects and carry-over contamination, when operated with a simultaneous multi-element atomic absorption continuum source spectrometer (SIMAAC). The three systems were a Perkin-Elmer HGA-500, an integrated contact cuvette furnace (spatially isothermal) and a two-step atomiser (spatially and temporally isothermal). High atomisation temperatures must be used in multi-element AAS if non-volatile elements are to be included. Therefore the facility of the two-step atomiser for selecting optimum temperatures regardless of the volatility of an element cannot be fully exploited. However, by using a consecutive two-stage constant-temperature atomisation procedure, optimum sensitivity could be achieved for volatile as well as refractory elements. The two furnace systems providing spatial isothermality were in general less susceptible to interference effects and, in addition, offered a significant reduction in carry-over contamination. This is of special importance in the SIMAAC system in order to utilise its facility of a dynamic calibration range of 5–6 orders of magnitude for each element.