Use of the median in the direct determination of cadmium in solid samples by electrothermal atomic absorption spectrometry

Abstract

The low precision of metal determinations by direct analysis of solid samples using electrothermal atomic absorption spectrometry can occasionally be ascribed to the presence of outliers. Their effect, however, can be lessened by using the median instead of the arithmetic mean, which improves on the precision of determinations. Thus, the direct determination of cadmium (10–100 µg g^–1) in solid samples of PVC by interpolation on a calibration graph run for the aqueous solution was achieved with a relative standard deviation of approximately 5% compared with approximately 10% by use of the arithmetic mean.