Microwaves absorption into food

The intensity of the absorption of microwave energy is a measure the abundance of that isotope. The potency of the NMR spectroscopy is not only its ability to quantify the concentration of an isotope, but to check the enviromnent into which an isotope is embedded. This is possible because the magnetic resonance and thus the absorption frequency prove to be sensitive to the spins of neighboring atoms and to structural features of the probe. Therefore, NMR spectroscopy is more a tool for scientific structural analyses than for daily food (colorant) inspection. For a detailed study of the NMR techniques used in food science we recommend books by Macomber and Pochapsky. - ... 

Vinas et al. (1993a), determined copper in biscuits and bread using a fast-program slurry electrothermal atomic absorption procedure and Miller-Ihli (1988) also used EAAS after slurry preparation for simultaneous multi-element AAS, as did Littlejohn et al. (1985) who introduced slurried food samples into the graphite furnace for analysis. Haswell and Barclay (1992), carried out on-line microwave digestion of slurry samples with direct flame atomic absorption spectrometric elemental detection. 

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