Analytical Procedures

CF-IRMS (e.g. Sercon GSL prep unit linked with IRMS)

Sample material is ground to a fine powder and weighed into tin capsules. Liquid samples are dried on to filter papers and loaded into tin capsules. During operation, the tin capsule falls into a combustion tube as a pulse of O2 is injected. Combustion products are swept through a purification train by a He carrier gas. The resulting N2 or CO2 is carried to the mass spectrometer by a capillary interface. The signals from the mass spectrometer’s collectors are integrated by a computer.

GC-C-IRMS (Agilent GC linked with IRMS)

Samples are injected onto a GC column for separation. Helium carries the the mixture eluting from the GC to a combustion furnace containing platinum and copper, which converts materials to N2 or CO2. Water is removed with a nafion membrane dryer and the entire gas sample is bled in to the mass spectrometer via a capillary interface. The signals from the mass spectrometer’s collectors are integrated by a computer.