A laser extraction/combustion technique for in situ δ ¹³C analysis of organic 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 the laser are quantitatively converted to CO2 gas by a combustion furnace mounted after the sample chamber. Gases produced by the laser and combustion processes are swept by helium carrier gas and separated by a packed gas chromatography column prior to their introduction to an isotope ratio monitoring mass spectrometer. A sample of lentil bean was analyzed at a spatial resolution 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), and IAEA CO-1 (calcium carbonate). Copyright (C) 1999 John Wiley & Sons, Ltd. [References: 9