QUANTITATIVE TRACE ELEMENT ANALYSIS OF MICROSAMPLES

COMMERCIALLY AVAILABLE GLOW-DISCHARGE MASS SPECTROMETRY (GDMS) AND HIGH-PERFORMANCE SECONDARY ION MASS SPECTROMETRY (SIMS) INSTRUMENTATION WILL BE EVALUATED FOR QUANTITATIVE TRACE ELEMENT ANALYSIS OF VERY SMALL BIOLOGICAL SAMPLES. SUBMILLIGRAM OR MICROLITER QUANTITIES OF BOVINE SERUM, BOVINE LIVER, AND RICE FLOUR, CERTIFIED BY THE NATIONAL BUREAU OF STANDARDS, WILL BE ANALYZED FOR THE ELEMENTS NA, K, CA, MN, FE, CO, CU, ZN, AND SE, AMONG OTHERS, AS A MEANS OF SIMULATING SMALL QUANTITIES OF TYPICAL BIOLOGICAL UNKNOWNS. QUANTITATION STUDIES WILL BE PERFORMED, USING INTERNAL STANDARD, STANDARD ADDITIONS, AND ISOTOPE DILUTION METHODS TO ASSESS ACCURACY AND PRECISION AS A FUNCTION OF SAMPLE SIZE AND ANALYTICAL PROTOCOL. THERE ARE MANY POTENTIAL HEALTH-RELATED APPLICATIONS FOR QUANTITATIVE MICROTRACE ELEMENT ANALYSIS IN NEONATOLOGY, NUTRITION STUDIES, OPHTHAMOLOGY, TOXICOLOGY, AND BASIC PHYSIOLOGICAL RESEARCH. CONVENTIONAL TECHNIQUES SUCH AS OPTICAL EMISSION, ABSORPTION SPECTROSCOPY, AND ELECTRON MICROPROBE ANALYSIS ARE INADEQUATE FOR THESE PROGLEMS. GDMSAND HIGH-PERFORMANCE SIMS ARE IDEAL CANDIDATE TECHNOLOGIES BECAUSE OF THEIR VERY LOW GRAM DETECTABILITIES (<1 PG AND <1 FG, RESPECTIVELY). SUBSTANTIAL MODIFICATIONS TO EXISTINGINSTRUMENTATION OR PROCEDURES IN PHASE II WILL PROBABLY BE REQUIRED TO ACHIEVE QUANTITATIVE TRACE ELEMENT ANALYSIS IN MICROSPECIMENS COMPARABLE TO CONVENTIONAL ANALYSIS OF LARGER SAMPLES.