“…The micro-analytical capabilities of TXRF spectrometry can play a vital role in clinical studies by determining elemental profiles and their anomalies for individual patients. Only 40–70 mg of a cleaned nail clipping was needed 55 to study profiles of As, Br, Ca, Cr, Cu, Fe, K, Mn, Ni, P, Ti, S, Se, V and Zn in patients with colon cancer. In comparison with the data from a control group, the nails of men with colon cancer had significantly lower concentrations of Ca ( p < 0.05) and Zn ( p < 0.05) and higher concentrations of As ( p < 0.05), Cr ( p < 0.05), Cu ( p < 0.001), Fe ( p < 0.001) and Se ( p < 0.001).…”