No abstract

We determined stable carbon, nitrogen, and oxygen isotopic compositions (δ13C, δ15N, and δ18O) of fibers to discriminate between plant, animal, and synthetic fibers. The δ13C and δ15N values of synthetic fibers are significantly lower than animal fibers. Cashmere and alpaca have relatively lower δ18O values than other animal fibers. Moreover, there are significant differences between acrylic and cashmere (e.g., in δ15N values). These results suggest that the stable carbon, nitrogen, and oxygen isotope analysis would be useful in discrimination of natural and synthetic fibers.

We examined the 13C/12C and 18O/16O stable isotope ratios (δ13C, δ18O) of ascorbic acid from acerola and of synthetic origin. Although the obtained δ13C values were partially overlapping for the two species, δ18O values were higher for ascorbic acid from acerola, than values obtained for synthetic ascorbic acid. From this study, it was demonstrated that carbon and oxygen isotopic composition analysis can discriminate ascorbic acid from acerola from that of synthetic origin.