Methods of Organic Analysis

In the laboratory, the most common instrument for the study of organic remains 

While chromatographic methods separate chemical compounds, they do not identify them as specific compounds. For this purpose one needs a good knowledge of what is most likely to be in the mixture. Known control substances can be analyzed along side the unknown samples. Discrete bands of the various components can then be identified against the known material that travels the same distance on the paper or glass sheet (Fig. 4.34). 

TLC and paper chromatography, while quite simple and inexpensive, are limited in their application to relatively simple mixtures. More sophisticated instrumental methods have been developed that allow smaller samples to be analyzed with much better resolution of different compounds. These methods also use the same principal of using stationary and mobile phases based upon a specific physical property that isolates the components of the mixture (Fig. 4.35). The most widely used methods 

Instrumental methods differ from paper and TLC in that the sample components 

These instrumental methods also have lunitations in that they do not provide a specific identification of the components they record. For relatively common mixtures with known components, reference substances can be run through the instrument and results compared to the unknowns. Because archaeological materials are old and organic components have decomposed over time, there is a need to identify a broad array of complex mixtures and their often-incomplete contents. 

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AktivKemiMineralGeol A22, No 10(1946) (Electrophoresis by the moving boundary method) 5) A. Weissberger, Physicochemical Methods of Organic Analysis , VanNostrand, NY, Vol 1(1949), pp 1685—1712 6) R.E. Kirk D.F. Othmer, Edits, Encyclopedia of Chemical Technology", Interscience,... 

Belcher, R. Submicro Methods of Organic Analysis. Amsterdam-London-New York Elsevier Publish Comp. 1966. 

At the time of their meeting, Liebig, though twenty-one, was professor of chemistry at the small University of Giessen. He had received this appointment through the influence of Von Humboldt, the celebrated scientist, whom he had met in Gay-Lussac s laboratory in Paris. His salary amounted to only one hundred and twenty dollars a year plus about forty dollars for annual laboratory expenses It was here that Liebig invented and developed a method of organic analysis still used today. 

Kirk 8c Othmer 5(1950), 175-9 (under Distillation by E.G.Scheibel) 9)A.Weissberger, "Physical Methods of Organic Analysis," Interscience, NY, 4(1951), 356-85(Azeo-tropic Distillation by C.S.Carlson) 10) Ullmann 1(1951), 431ff (Destination) 11)... 

V.A. Klimova, Osnovnye Micrometody Analiza Organicheskikh Soedineniy (Basic Micro Methods of Organic Analysis), Khimiya, Moscow, 1975. 

Attempts at quantitative organic analysis were made by T. de Saussure, who analysed gum arable and colophony, and by Berthollet. The first really successful general method of organic analysis was that of Gay-Lussac and Thenard. ... 

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