BIOLOGICAL SAMPLE PREPARATION AND CA-41 AMS MEASUREMENT AT LLNL

Calcium metabolism in biology may be better understood by the use of Ca-41 tracer, although requiring detection by accelerator mass spectrometry (AMS). Methodologies for preparation of urine samples and subsequent AMS measurement were investigated. Novel attempts at preparing CaH2 were unsuccessful, but CaF2 of sufficient purity could be produced by precipitation of calcium from urine as oxalate, followed by separation of calcium by cation exchange chromatography and washing the CaF2 precipitate. The presence of some remaining impurities could be compensated for by selecting the appropriate accelerated ion charge state for AMS. The use of projectile X-rays for isobar discrimination was explored as an alternative to the conventional dE/dx detector.