A COMPARISON OF THE TECHNIQUES OF SECONDARY-ION MASS-SPECTROMETRY ANDRESONANCE IONIZATION MASS-SPECTROMETRY FOR THE ANALYSIS OF POTENTIALLY TOXIC ELEMENT ACCUMULATION IN NEURAL TISSUE

A comparison is made of the techniques of secondary ion mass spectrome try (SIMS) and resonance ionization mass spectrometry (RIMS) for the d etection of the neuro-toxic element aluminium in cortical tissue, Expe riments were performed using a reflectron-type time-of-flight mass spe ctrometer (TOFMS) in conjunction with an Ar+ source for target sputter ing and a pulsed tuneable dye laser system for resonance ionization. I t is shown how isobaric interference of species such as CNH and C2H3 i n the case of aluminium greatly affect the quantitative accuracy and t he detection limit of aluminium in biological samples when analysed us ing SIMS, In contrast the use of RIMS virtually eliminates this proble m, so allowing easier quantification and much lower detection limits t o be achieved, Detection limits of similar to 3 ppm for aluminium in b rain tissue homogenates were achieved using RIMS, with a spatial resol ution of less than 100 mu m. (C) 1997 by John Whey & Sons, Ltd.