Natural origin of ascorbic acid: validation by 13C-NMR and GC-C-IRMS

A new method for the extraction and purification of ascorbic acid from two tropical fruits (acerola and camu-camu) is presented. 13C nuclear magnetic resonance and isotopic ratio mass spectroscopy (13C/12C) were used to recognize ascorbic acid coming from either natural or industrial sources. A quantitative 13C NMR procedure was optimized to calculate isotopic relative abundances on each molecular site; data were treated by a multivariate method. Samples were also analysed by IRMS coupled with gas-chromatography/combustion and elemental analysis devices. The combined use of these techniques enabled us to validate the origins of ascorbic acid batches issuing from different sources.