Microsampling Isotope Ratio Mass Spectrometer Development
EMSL Project ID
28393
Abstract
We are using a combination of laser ablation, catalytic reactor technology, and systems engineering to develop a novel device that converts the O and H in solid organic samples to CO and H2, respectively, and introduces them into an existing isotope ratio mass spectrometer to determine H/D and 12C/13C ratios. The quantity of sample required for analysis will be reduced by greater than a factor of 50 compared to existing instruments, providing the ability to determine isotope ratios in microgram or smaller samples. Applications will include sections of biofilms, atmospheric aerosol particles, and segments of hair.The solid sample is converted by laser ablation into small particles (~300 nm) which can be efficiently and quantitatively transported into a gas stream for further processing. The particles are quantitatively converted into CO and H2 by pyrolysis in a catalytic tube reactor coated with carbon and catalyst to maintain reducing conditions and allow for elevated temperature (>1200 C) conversion. The gas is then introduced into a micro-capillary gas chromatograph to separate the two gases. Finally, detection occurs in an isotope ratio mass spectrometer. Currently, we have demonstrated the ability to ablate the sample into particles, and quantitatively convert gaseous samples into H2 and CO at the appropriate gas flow rates. During this year of the project we will demonstrate ablation under carrier gas flow rates compatible with the rest of the system, couple all the pieces together and demonstrate acceptable precision and accuracy in the isotope ratios measured by the IRMS instrument using this new sample introduction system.
Project Details
Project type
Exploratory Research
Start Date
2008-01-23
End Date
2009-01-25
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Hu J, RA Dagle, BR Johnson, HW Kreuzer, DJ Gaspar, BQ Roberts, and ML Alexander. 2008. "Development of Micro Pyrolyzer for Enhanced Isotope Measurement." Ind. Eng. Chem. Res. 2008, 47, 8625–8630.