MDGC-C/P-IRMS

Sewenig S, Bullinger D, Hener U, Mosandl A (2005) Comprehensive authentication of (E)-a(/ )-ionone from raspberries, using constant flow MDGC-C/P-IRMS and enantio-MDGC/... 

FIGURE 2.7 Scheme of an MDGC-C/P-IRMS device. (From Sewenig, S. et al., J. Agric. Food Chem., 53, 838, 2005. With permission.)... 

Most flavourings are complex mixtures of many compounds. As IRMS makes only sense with pure analytes, a strict purification of individual substances is indispensable. Therefore GC-IRMS has been further developed and optimised to multi-compound isotope ratio analysis by its coupling IRMS to capillary (c) and multidimensional (MD) gas chromatography (see 6.2.2.2.2). This methodology demands a strict intrinsic control and standardisation [340] apart from the international standards (see Table 6.3) also secondary standards like the polyethylene foil IAEA-CH7 or the NBS22 oil are available from the IAEA in Vieima. However, as these substances are also not suitable for the direct standardisation of data from a coupled GC system for flavour isotope analysis, certificated tertiary laboratory standards for hydrogen have been developed by parallel analysis of flavour compounds by TC/EA-IRMS and MDGC-P-IRMS [210]. 

B. Weckerle, R. Bastl-Borrmann, E. Richling, K. Hor, C. Ruff, P. Schreier (2001). Cactus pear (Opuntia ficus indica) flavour constituents - chiral evaluation (MDGC-MS) and isotope ratio (HRGC-IRMS) analysis. Flav. Fragr. 1.16. 360-363... 

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