USE OF THE SIMPLIFIED GENERALIZED STANDARD ADDITIONS METHOD FOR CALIBRATION IN SOLID SAMPLING ELECTROTHERMAL VAPORIZATION INDUCTIVELY-COUPLED PLASMA-ATOMIC EMISSION-SPECTROMETRY

To find a useful calibration strategy for the direct analysis of solid samples by electrothermal vaporization inductively coupled plasma atomic emission spectrometry (ETV-ICP-AES), the simplified generalized standard additions method was investigated. This method leads, by varying both the mass of the solid sample and the amount of analyte (standard solution) added, to a response surface from which the analyte concentration can be deducted by multiple linear regression. The analytical results obtained for Cu, Pb and Cd determinations in a number of biological and environmental reference materials are in good agreement with the certified values. The number of data points required to yield precise results (typical RSD<10%) depends on the sample homogeneity.