The effect of heterogeneity on the accuracy of analytical results was experimentally investigated for some biologically important elements in hair, viz. S, Cl, K and Ca. Measurements were carried out by energy‐dispersive x‐ray fluorescence spectrometry using annular 55Fe radioisotope source excitation. The differences between the concentration values from direct hair analysis, using bunches of hair strands for the measurements, and those from ground and pelletized hair samples were compared. On average, the discrepancy in the measured concentrations was ca. 5% for Ca, whereas for S, Cl and K it was higher at ca. 10–15%. Good agreement was found between the experimental values and the theoretical predictions of other workers.
ASJC Scopus subject areas