Quantification of trace elements in normal human brain by inductively coupled plasma atomic emission spectrometry

Eight normal human brain autopsy samples were analyzed for Na, K, P, Ca, Mg, Si, Cr, Cu, Ni, Zn, Fe, Al, Cd, Pb and As in 12 regions of brain (frontal cerebrum, temporal cerebrum, parietal cerebrum, somatosensory cortex, occipital cerebrum, cerebellum, mid-brain, pons, hypothalamus, thalamus, hippocampus and medulla oblongata) using inductively coupled plasma atomic emission spectrometry (ICPAES). The distribution of these 15 elements varied significantly from region to region of the brain. Potassium was most abundant in nearly all regions of the brain, followed by sodium and phosphorus (mg/g). The concentration of Al was found to be comparatively high and varied in different areas of the brain (58-196 microg/g). Moderate levels of Pb, Cd and As were observed in different regions. Ratios of Al to Fe were found to be high in temporal cerebrum (8.07) and hippocampus (9.05) and these two regions are significantly involved in Alzheimer's disease. The concentration of Na in mole percentage showed an inverse correlation with that of K, Ca, Mg, Fe and Cr. Direct correlation was observed in the concentration of all analyzed elements, which indicated for the first time the direct dependency of concentration of trace elements in one brain region to other regions. The mole ratios between different elements in different brain regions and total amounts of the elements in an average weight of 1.4 kg human brain were also computed. The present study provides new and in-depth data which may be used as base line data for normal human brains.