Figure 3.
Difference plots (XRF – ICP-OES value) for Pb, As, and Hg in powdered samples measured with the XOS prototype and the Niton; left side shows all results, right includes only low mg/kg range; XRF(n=3, error bars +/− SD), dashed lines indicate +/− 50% of reference value; HMP (herbal medicine product), ES (ethnic spice), CP (cosmetic product)