Carbohydrate 13C Analysis
Sugars are analyzed for 13C using a Surveyor HPLC coupled to a Delta Plus isotope ratio mass spectrometer through a Finnigan LC Isolink interface (Thermo Electron Corp.). Sugars are separated on a CarboPac PA20 column (3 x 150 mm; Dionex Corporation, Sunnyvale, CA, USA) isocratically at 0.3 mL/min at 25ºC. The mobile phase for neutral sugars is 1mM NaOH; the mobile phase for acidic sugars is 1mM NaOH + 2 mM NaNO3. After separation, the column eluent is mixed with sodium peroxidisulfate (0.8 M) and phosphoric acid (1.7 M), separately pumped at 50 µL/min. Individual sugar peaks are then quantitatively oxidized to CO2 as the mobile phase flows through an oxidation reactor at 99.9ºC. Each CO2 peak is transferred from aqueous phase to He carrier gas (2 mL/min) in a separation unit. Following water removal using a two-stage Nafion™ drier, the CO2 peaks enter the IRMS through an open split.
References
Boschker, H.T.S, Moerjijk-Poortvliet, T.C.W., van Breugel, P., Houtekamer, M., and Moddelburg, J.J. 2008. A versatile method for stable carbon isotope analysis of carbohydrates by high-performance liquid chromatography/isotope ratio mass spectrometry. Rapid Communications In Mass Spectrometry 22:3902-3908.
e-mail: sif@ucdavis.edu | phone: 530-752-8100 | fax: 530-752-4361 UC Davis Stable Isotope Facility | Department of Plant Sciences One Shields Avenue, Mail Stop #1 | Davis, California, 95616 | USA |