Premium
Rapid quality control analysis of 13 C‐enriched substrate synthesis by isotope ratio mass spectrometry
Author(s) -
Morrison Douglas J.,
Dodson Brian,
Preston Tom,
Weaver Lawrence T.
Publication year - 2001
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.341
Subject(s) - chemistry , isotope ratio mass spectrometry , lactose , mass spectrometry , urea , chromatography , substrate (aquarium) , organic chemistry , oceanography , geology
There is a growing interest in the use of 13 C‐enriched substrates to investigate metabolic processes in humans. The non‐invasive nature of 13 C breath tests makes them attractive to clinicians, particularly because they can be safely used in children. The availability of suitable 13 C‐enriched substrates can limit the application of this biotechnology. We have used isotope ratio mass spectrometry to assay the chemical purity and isotopic enrichment of substrates that were synthesised to study gut transit and colonic fermentation. Lactose ureide and lactose [ 13 C]ureide were synthesised by acid‐catalysed condensation of lactose and urea or 13 C urea, respectively. Glucose ureide and glucose [ 13 C]ureide were synthesised by similar methods but required an additional purification step to remove urea of crystallisation. Substrates were analysed by standard analytical techniques and combustion isotope ratio mass spectrometry for carbon and nitrogen content and 13 C‐enrichment. Monitoring the C/N ratio proved to be a sensitive assay of chemical purity. Analysis of the percentage composition of C and N (and hence O + H) suggested that lactose ureide crystallises as the dihydrate. It was synthesised with ∼99% chemical purity and with the theoretical enrichment. Glucose ureide was synthesised with ∼98% chemical purity but with lower than theoretical enrichment. Copyright © 2001 John Wiley & Sons, Ltd.