Ultramicroanalysis of dental plaque films by total reflection X-ray fluorescence

Microgram quantities of dental plaque were taken near amalgam fillings, gold crowns and intact teeth. Such extremely small samples can be analysed by total reflection X-ray fluorescence (TXRF), a fairly new variant of energy dispersive X-ray fluorescence (EDXRF). More than sixty samples were examined directly without chemical pretreatment. Fifteen elements of interest were detected simultaneously within a wide range of mass fraction and with detection limits of several mg/kg. A significant correlation of the Hg-accumulation in plaque and the amalgam fillings was established. Near these fillings Hg mass fractions can reach a level of 300 mg/kg. The results for other elements, e.g. Au, are less significant.