ANALYSIS OF TRACE-ELEMENTS IN THE CENTRAL NERVE TISSUES WITH INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY

To investigate the roles of various elements in neurological disorders , multi-element analysis of limited quantities of samples in the centr al nervous system is required. Inductively coupled plasma-mass spectro metry (ICP-MS) analysis suits this requirement, but spectral and non-s pectral interferences are inevitable. We studied correction methods fo r the non-spectral interferences by analyzing signals of 21 elements i n various concentrations of HNO3 as well as 5 major elements (Na, K, P , Ca, and Cl). Using internal standards, the interferences caused by t he major elements were corrected, but the interferences caused by HNO3 were impossible to correct for the elements with high ionization pote ntials. Thus, me decided to use a standard addition method to correct these interferences. The spectral interferences on Mn and Fe rising fr om HNO3 or major elements were compared with the signals of samples. A lthough the interferences on Mn mere negligible, those on Pe were cons iderable and careful blank subtraction were needed. We measured concen trations of elements in the spinal cord of 4 controls and a patient wi th amyotrophic lateral sclerosis (ALS) using the standard addition met hod. The concentrations of Mn, Se, Fe, and Zn in the controls mere nea rly the same as previously reported values, whereas Mn concentrations in the ALS patient mere higher.