Numerous techniques are employed to isolate nitrogen-containing heterocyclic aroma compounds for chemical characterization and/or quantitation. These include: solvent extraction, adsorption and ion exchange chromatography, molecular and steam distillation, static and dynamic headspace sampling and solid phase micro-extraction. Gas chromatography-mass spectrometry is used most commonly to identify the isolated compounds. However, other analytical techniques used to characterize and/or quantify nitrogen heterocycles include multidimensional chromatography and gas chromatography-olfactometry, as well as gas chromatography with various types of nitrogen-specific detection or atomic emission detection. The most commonly employed of these techniques are described, and examples are cited of their use in analyzing food and beverage flavors for nitrogen heterocycles.
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