Liquid chromatography , natural hyphenated separation techniques

As liquid chromatography plays a dominant role in chemical separations, advancements in the field of LC-NMR and the availability of commercial LC-NMR instrumentation in several formats has contributed to the widespread acceptance of hyphenated NMR techniques. The different methods for sampling and data acquisition, as well as selected applications will be discussed in this section. LC-NMR has found a wide range of applications including structure elucidation of natural products, studies of drug metabolism, transformation of environmental contaminants, structure determination of pharmaceutical impurities, and analysis of biofiuids such as urine and blood plasma. Readers interested in an in-depth treatment of this topic are referred to the recent book on this subject [25]. 

Efficient detection and rapid characterisation of natural products play an important role as an analytical support in the word of phytochemists. The identification of a metabolite at the earliest stage of separation is a strategic element for guiding an efficient and selective isolation procedure. In this respect, the role of hyphenated techniques such as high performance liquid chromatography coupled to mass spectrometry (LC/MS) or to nuclear magnetic resonance (LC/NMR) has became of great interest. 

Mass spectrometry, on its own, does not find much, if any, use in forensic science due to the nature of the samples that are analysed (sample matrices tend to very complex, e.g., blood). In this section, we shall look at the aspects of mass spectrometry as it relates to hyphenation with liquid chromatography. Hyphenation is the combining of the two techniques whereby HPLC is used to separate a mixture of components each analyte is introduced into the mass spectrometer as a single compound (i.e., no longer part of the matrix of the original sample). 

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