Thin-Layer Chromatography

[7] Kelker, H.: Nachr. Chem. Techn. Lab. 1983, 31, 786.
[8] Stahl, E.: DUnnschicht-Chromatographie, ein Laboratoriumshandbuch 2nd Ed Springer
Berlin 1967. '
[9] Kirchner, J. G.: Thin-Layer Chromatography, 2nd Ed., Wiley, New York 1978.
[10] Randerath, K.: Dilnnschicht-Chromatographie. 2nd Ed., Verlag Chemie, Weinheim 1965
[11] E. MERCK, Company brochure "Dyeing Reagents for Thin Layer and Paper Chromatography",
Darmstadt 1980.
[12] Wallhauser, K. H.: in [8].
[13] Jork, H.: GITFachz. Lab. Supplement 3 ..Chromatographie" 1986, 30, 79-87.
[14] Jork, H., Wimmer, H.: QuantitativeAuswertung von Dtinnschicht-Chro'matogrammen 1986,
Arbeitsblatt 1/1-7 und 1-8. GIT-Verlag, Darmstadt 1986.
2 Physical Methods of Detection
2.1 General
Physical detection methods are based on inclusion of substance-specific properties.
The most commonly employed are the absorption or emission of electromagnetic
radiation, which is detected by suitable detectors (the eye, photomultiplier). The
^-radiation of radioactively labelled substances can also be detected directly. These
nondestructive detection methods allow subsequent micropreparative manipulation
of the substances concerned. They can also be followed by microchemical
and/or biological-physiological detection methods.
A distinction is normally made between the visible and ultraviolet regions of the
spectrum when detecting absorbing substances. Detection in the visible part of the
spectrum can be carried out with the eye or with a photomultiplier.
2.2 Detection of Absorbing Substances
2.2.1 Visual Detection
The success of separation of colored compounds is usually monitored visually.
Such compounds absorb a particular portion of the polychromatic (white) light
in the visible wavelength range. The remaining radiation (complementary radiation)
is reflected and detected by the eye; it determines the color of the substance
zone. Table 1 correlates the wavelengths, colors and complementary colors.
Table 1. Correlation of wavelength, color and complementary color [1].
Wavelength
fnml
620...700
590...620
57O...59O
500...570
450...500
400...450
Color of radiation Complementary color
red
orange
yellow
green
blue
violet
bluish-green
greenish-blue
blue
red/purple
yellow
yellowish green