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We have a total of four isotope ratio mass spectrometers and one GC-MS
#1 Micromass OPTIMA machine linked to elemental analyser inlet.
Used for background 15N and 13C determinations in organic matter and more rarely nowadays for 15N measurements in tracer studies of protein turnover. We bought this machine in 1991 when the lab was first established. At that stage we used the 10 manual inlet ports to run hydrogen and oxygen (CO2) that had been manually prepared offline (for hydrogen this was initially by zinc reduction and then by lithium aluminium hydride) for oxygen analysis we used the guanidine technique. We bought the elemental analyser in 1992 and expanded its capacity in 1995.
example publication : Perkins, S.E. and Speakman, J.R.(2001) Measuring natural abundance of C-13 in respired CO2: variability and implications for non-invasive dietary analysis. Functional Ecology 15:791-797.
#2: Micromass isoprime microG
We bought this machine in 2000 partly funded by a REI equipment grant from BBSRC and partly funded by industry sponsorship from the Watham Centre for Pet Nutrition. The machine is used for measurement of oxygen isotope enrichments from waters derived from blood as part of the DLW method using the small sample equilibration method.