Hyphenated analytical techniques

Coupling of analytical techniques (detectors) to high-performance liquid chromatographic (HPLC) systems has increased in the last tree decades. Initially, gas chromatography was coupled to mass spectrometry (MS), then to infrai ed (IR) spectroscopy. Following the main interest was to hyphenate analytical techniques to HPLC. 

Coupled (hyphenated) analytical techniques of a separation method and a method of analytical determination, e.g. GC-MS, see Fig. 3.13, by which higher-dimensional signal functions are obtained. Strictly speaking, the dimension is 2(n + 1) in the case that n mass spectra are recorded. 

J. Rosenfeld (Ed.), Sample Preparation for Hyphenated Analytical Techniques, Blackwell, Oxford,... 

Lespes G, Gigault J. Hyphenated analytical techniques for multidimensional characterisation of submicron particles a review. Anal. Chim. Acta 2011 692 26-41. 

Hyphenated analytical techniques such as LC-MS, which combines liquid chromatography and mass spectrometry, are well-developed laboratory tools that are widely used in the pharmaceutical industry. Eor some compounds, mass spectrometry alone is insufficient for complete structural elucidation of unknown compounds nuclear magnetic resonance spectroscopy (NMR) can help elucidate the structure of these compounds (see Chapter 20). Traditionally, NMR experiments are performed on more or less pure samples, in which the signals of a single component dominate. Therefore, the structural analysis of individual components of complex mixtures is normally time-consuming and less cost-effective. The... 

The first part of this section (Section 20.2.1) will provide the reader with historical overview of NMR and with a brief description of the most typical experiments used in NMR for the structural elucidation of organic compounds. The second part of this section (Section 20.2.2) will focus mainly on the improvements carried out in the NMR as a hyphenated analytical technique for the elucidation of organic compounds and an understanding of the need to develop LC-NMR for the analysis of complex mixtures. 

The process for identification of a trace level organic impurity in a pharmaceutical product can be viewed in a systematic way. One commonly used paradigm is based on MS and the hyphenated analytical techniques... 

Figure 6 Example of MDGC with multiple heartcuts (each heartcut required a separate injection) and separate analysis of each heartcut. result for heartcut event 14 is shown. (Reproduced with permission from Gordon BM, Uhrig MS, Borgerding MF, etal. (1988) Analysis of flue cured tobacco essential oil by hyphenated analytical techniques. Journal of Chromatographic Science 26 174-180 Preston Industries, Inc.)...

During the last two decades, hyphenated analytical techniques have become fairly commonplace. Multimode separation and detection strategies are required in such... 

Hu, L., Ye, M., Jiang, X., Feng, S., Zou, H. (2007) Advances in Hyphenated Analytical Techniques for Shotgun Proteome and Peptidome Analysis - a Review. Anal. Chim. Acta 598 193-204. 

Recent advances in hyphenated analytical techniques, where a separation device is coupled online with detectors generating spectral information, have remarkably widened the analysis field of complex biological matrices. During the last few years covered by this chapter, a number of papers describing the application of TLC, GC-MS, HPLC-UV, HPLC-UV/MS, CE-MS, and NMR to the qualitative and quantitative analysis of tropane alkaloids in toxicological, physiological, forensic, phytochemical, and chemotaxonomical studies have been published. 

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