Difficult mixture analysis problems can usually be simplified when chromatographic separating techniques are employed to isolate individual mixture components. Many different discrimination methods based on observation of physical or chemical properties have been developed to detect substances Separated by gas chromatography. These detectors facilitate quantitative analysis when mixture component identities are known but provide little structural information for identification of unknown mixture components. On the other hand, mass spectrometry and infrared spectroscopy can provide a wealth of structural information. Mass spectra and infrared spectra are representative of eluent structure in a complementary manner. Mass spectrometry is often used to obtain molecular weight information and can be used to distinguish homologues. Infrared spectra reveal molecular functionalities and are particularly useful for isomer discrimination.
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