High accelerated mass spectrometry

Ann McNichol is a Research Specialist at the National Ocean Sciences Accelerator Mass Spectrometry Facility at the Woods Hole Oceanographic Institution, which produces high-precision 14C measurements from small-volume samples. Dr. McNichol s research interests include the study and use of carbon, nitrogen, and oxygen isotope techniques to quantify bio-geochemical processes, the study of the fate of organic matter (both natu-... 

Ognibene, T. J., Bench, G., Vogel, J. S., Peaslee, G. F., and Murov, S. (2003). A high-through-put method for the conversion of CO2 obtained from biochemical samples to graphite in septa-sealed vials for quantification of 14C via accelerator mass spectrometry. Anal. Chem. 75 2192-2196. 

Ognibene, T. J., and Vogel, J. S. (2004). Highly sensitive 14C and 3H quantification of biochemical samples using accelerator mass spectrometry. In Synthesis and Applications of Isotopically Labelled Compounds (Dean, D. C., Filer, C. N., and McCarthy, K. E., Eds.). Wiley, Hoboken, NJ, pp. 293-295. 

A promising alternative to the conventional radio-analytical measurement of C-14 in hADME studies is Accelerated Mass Spectrometry (AMS), which can operate as a detector for C-14 with an increase of sensitivity by a factor of 1000 (Gamer 2000). This technique is complex and presently not used routinely. In addition, as an alternative, the last-generation, high-sensitivity liquid scintillation beta counters show an increase of sensitivity by a factor of 10-20. In those cases where the dosimetric calculations indicate that a traditional dose (2-4 MBq) would result in an... 

The Faraday cup was widely used in the beginning of mass spectrometry but all the characteristics of this detector mean that it is now generally used in the measurement of highly precise ratios of specific ion species as in isotopic ratio mass spectrometry (IRMS) or in accelerator mass spectrometry (AMS). To obtain a highly accurate ratio in such relative abundance measurements, the intensities of the two stable beams of specific ions are measured simultaneously with two Faraday cups. 

As a highly selective and very sensitive isotopic analytical technique, accelerator mass spectrometry (AMS) is able to determine radionuchdes ( °Be, C1, A1, Tc, Np, Pu... 

Lappin, G. et al., High-performance liquid chromatography accelerator mass spectrometry Correcting for losses during analysis by internal standardization, Anal. Biochem., 378(1), 93, 2008. 

Because use of mass spectrometry by chemists has increased greatly, most U.S. chemists have access to mass spectrometry facilities at their own institutions to confirm synthesis and support structure elucidations. Heavily used national centers provide more expensive instrumentation and more complex experiments. Most notably, a section of the National High Magnetic Field Laboratory at Florida State University provides state-of-the-art Fourier transform ion cyclotron resonance mass spectrometry. The NSF Arizona Accelerator Mass Spectrometry Laboratory is used primarily to provide radiocarbon measurements. NIH funds a number of national mass spectrometry centers to support biomedical research, including those at Boston University and the Pacific Northwest National Laboratory. 

Tomy GT, Stem GA (1999) Analysis of C14-C17 polychloro-n-alkanes in environmental matrices by accelerated solvent extraction-high-resolution gas chromatography/electron capture negative ion high-resolution mass spectrometry. Anal Chem 71 4860-4865... 

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