The influence of the variable sample volume and constant added standard on the determination of copper, nickel and chromium by atomic absorption spectrometry

Bader indicated as the most convenient approaches for the determination of an element by atomic absorption spectrometry the (1) continuous variation of standard at constant total volume, and (2) continuous variation of the unknown analyte at constant total volume. Considering the relevance of the ease of atomization, Bader's statement were put to the test in the determination of copper, nickel, and chromiun in nodular iron by use of analysis of variance (ANOVA). The results presented here lead to the conclusion that Bader's modes (1) and (2) are not equivalent for all cases.