HPLC-hyphenated techniques

Chromatography, detailed in previous chapters, is one of the most widely employed analytical methods. Chromatography serves to separate species into ideally individual constituents. However, as the technique has evolved and separation performance has increased, scientists are discovering that what they once thought may have been individually resolved isolated components from within mixtures, may now be combinations of coeluting species. ID chromatography cannot be used to identify species as retention times are not unique. This fact, together with the need to evaluate complex sample matrices, has driven the demand for techniques to be developed that are complementary. As we seek to gain more information regarding the constitution of sample matrices and subsequent quantitation, methods of analysis necessarily become more sophisticated. The increase in separation performance and analysis has followed two paths. There is currently growth in the development of multidimensional methods of analysis namely, coupled chromatographic systems. In particular, multidimensional gas chromatographic methods of analysis have been heavily investigated, but more recently there has ben growing interest in multidimensional separations in liquid chromatography. The second path has been in the development of coupled and complementary methods of analysis; that is, chromatography, which is employed for its ability to bring about separation, and other analytical methods of analysis for detection and identification of species. This has developed into what is now referred to as hyphenated methods of analysis.