SIRA, stable isotope ratio analysis

Detection of adulteration in fruit juices. SNIF/NMR (deuterium) and SIRA/MS (stable isotope ratio analysis/mass spectrometry). [67]... 

Stable isotope ratio analysis (SIRA, GC-IRMS [Gas Chromatography-Isotope Ratio Mass Spectrometry], and Site Specific Isotope Fractionation — Nuclear Magnetic Resonance [SNIF-NMR]) have proven useful in many adulteration situations. In nature, and exist at relative proportions of 1.11 98.89 [27]. The photosynthetic process selectively enriches the plant in dependent upon the type of photosynthetic process used by the plant. Plants using the Hatch-Slack pathway (e.g., com, sugar cane, millet, and lemon grass) give 8 C values the closest to the standard, i.e., 5 C values of ca. -10. The 5 C value is calculated as ... 

The isotopic distribution found in natural F F compounds serves as a signature that analysts can use to differentiate natural compounds from synthetic analogs. The metabolic pathways that plants use to create carbon compounds discriminate between C and C. The C/ C ratio of the carbon dioxide the plant uses as a reactant differs from the C/ C ratio of the compounds the plant produces. Stable carbon isotope ratio analysis (SIRA) measures the C/ C ratio and can authenticate the natural or synthetic origins of some F F materials. SIRA applied to isotopes of hydrogen, or D and H can also serve to authenticate natural F F materials. When combined with GC the on-line or D/ H SIRA analysis can authenticate each component in a complex mixture such as a cinnamon bark oil (19). 

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