A laser extraction combustion technique for in situ delta C-13 analysis oforganic and inorganic materials

A CO2 laser extraction system is described for in situ delta(13)C analysis of organic and inorganic materials. Carbonaceous compounds volatilized by t he laser are quantitatively converted to CO2 gas by a combustion furnace mo unted after the sample chamber. Gases produced by the laser and combustion processes are swept by helium carrier gas and separated by a packed gas chr omatography column prior to their introduction to an isotope ratio monitori ng mass spectrometer. A sample of lentil bean was analyzed at a spatial res olution of 200 mu m and yielded delta(13)C values with precision of +/-0.3 parts per thousand. The accuracy of delta(13)C measurements was better than +/-0.5 parts per thousand from NBS 22 (mineral oil), USGS 24 (graphite), a nd IAEA CO-1 (calcium carbonate). Copyright (C) 1999 John Wiley & Sons, Ltd .