The method of standard addition has been widely used on various analyt
ical techniques. In this work atomic absorption spectrometry has been
tested. Analysis of nine elements: Na, K, Ca, Fe, Cr, Cu, Mg, Mn and Z
n in the clay sample yielded a concentration range within the expected
value. The precision of the measurement was found to be better than 2
% for most of the elements, although for low concentrations of Mg and
Na the precision was poor.