In Microanalysis of Biological Materials

Samples such as hair, nails, blood, urine, and various tissues are analyzed by NAA for both essential and toxic trace elements (Bhandari et al. 1987, Lai et al. 1987). The analysis can be related to determine their effect on disease outcomes. These authors have reported that the diet and environment contribute largely towards the trace elements in the human body. It is has been demonstrated in other works that the selenium concentration in human nails is an accurate monitor of the dietary intake of selenium. As a consequence, the nail monitor has been extensively used to study the protective effect of dietary selenium against cancer and heart disease in numerous prospective case-control studies. In another study by Kanabrocki et al. (1979) on human thumbnails in USA, using thermal NAA technique, the average concentration of metals studied in clinically symptom-free adult female and male subjects were found to be zinc, 184 vs. 153 ppm chromium, 6.8 vs. 4.2 selenium, 0.9 vs. 0.6 gold, 2.6 vs. 0.4 mercury, 1.9 vs. 0.4 silver 0.7 vs. 0.3 cobalt, 0.07 vs. 0.04. In another study, the fluorine concentration in bone biopsy samples was 

NAA has proven to be a most suitable method for the quantitative determination of a wide variety of trace (0.01-100 pg g ) and ultratrace ( 0.01 pg g ) elements in biological materials (Cornells 1985). In his review article Cohn (1992) has illustrated the applications of this technique of NAA in nutritional research. 

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