Further Reading

Bonmati R, Chapelet-Letourneux G and Guiochon G (1984) Separation Science and Technology 19 (2&3): 133-155.

Jacob L and Guiochon G (1971) Chromatography Review 14: 77.

Kovats E and Heilbronner E (1956) Chimia 10: 288. Rijnders GW (1966) In: Giddings JC and Keller RA (eds) Advances in Chromatography, p. 215. New York: Dekker.

Roz B, Bonmati R, Hgenbach G et al. (1971) Chromatog-raphia 4: 6.

Valentin P and Guiochon G (1975) Separation Science 10:

245, 271, 289. Valentin P, Hgenbach G, Roz B and Guiochon G (1976) Journal of Chromatographic Science 14: 367.

Why are multidimensional methods implemented for chromatographic analysis? The usual answer lies in the need for enhanced separation of closely eluting compounds - compounds with similar retention factor, k. Historically, chromatography has searched for better means to resolve compounds; as methods improve, we can separate compounds of closer chemical nature. Traditionally, chromatographers have improved column selectivity to provide a larger magnitude in differences of distribution constant, K (where K = kp cc tR; therefore larger retention time differences results from increased K differences), or increased efficiency of the chromatographic process with narrower chromatographic bands giving better resolution. The former is achieved by using a stationary phase or separation mechanism with greater discrimination between the solutes to be separated, and the latter by employing narrower-bore columns, smaller particle packing sizes or other physical means to reduce peak dispersion. Very soon in the historical development of GC, it was recognized that one stationary phase would probably not resolve many compounds (hence the plethora of stationary phases that were produced), but also that a given mixture can contain a range of different classes of compounds that may best be separated on different phases. Thus, improved separation may require two columns for the one analysis. Two separate columns means that

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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