Thin layer chromatography, applications instrumentation

Planar chromatography, also known as Thin Layer Chromatography (TLC), is a technique related to HPLC but with its own specificity. Although these two techniques are different experimentally, the principle of separation and the nature of the phases are the same. Due to the reproducibility of the films and concentration measurements. TLC is now a quantitative method of analysis that can be conducted on actual instruments. The development of automatic applicators and densitometers has lead to nano-TLC, a simple to use technique with a high capacity. 

Automatic scanning instruments are usually coupled to integrators or the integration is carried out by built-in microprocessors. With computer integrators, the user is tied to the application scheme provided by the integrator (arrangement of standards and samples on the plate). At times this scheme is not the most suitable one for the thin-layer chromatography. 

Another application to pre- and newborns was published by Liu et al. in 1997 [95]. In this paper, they presented a measure of fetal lung maturity from the spectra of amniotic fluid. The lecithin/spingomyrlin (L/S) ratio was determined by thin layer chromatography (TLC) and used to calibrate a NIR equation using the whole amniotic fluid extracted from pregnant women. About 350 iL of fluid was required. This was scanned from 400 to 2500 nm using a commercially available instrument. The correlation between further samples of fluid and TLC results was about 0.91, considered excellent for the complexity of the solution and extremely small sample size. Of course, a PLS equation was needed due to the complex nature of the samples. 

Instrumental methods for analysis depend on the natme of peroxide. Gas chromatography is applicable where peroxides are thermally stable. It may also be applied as a pyrolytic decomposition technique in which the decomposition products are separated and quantified (Swem 1986). Liquid and column chromatography, thin-layer chromatography, and paper chromatography have been used for analyses of peroxides. 

See also Atomic Absorption Spectrometry Principles and Instrumentation. Atomic Emission Spectrometry Principles and Instrumentation. Atomic Fluorescence Spectrometry. Gas Chromatography Pyrolysis Mass Spectrometry. Liquid Chromatography Normal Phase Reversed Phase Size-Exclusion. Polarography Inorganic Applications Organic Applications. Polymers Synthetic. Thin-Layer Chromatography Overview. Voltammetry Organic Compounds. 

Bl dek, J. Rostkowski, A. Miszczak, M. Application of instrumental thin-layer chromatography and solid extraction to the analyses of pesticide residues in grossly contaminated samples of soil. J. Chromatogr. 1996, 754, 273-278. 

This entry describes the general considerations, procedures, and instruments that are important for the correct application of sample and standard zones in thin-layer chromatography (TLC) and high-performance TLC (HPTLC). The application of spots and bands manually and by semiautomated and completely automated instrumental techniques is covered. 

In the following section, three approaches are focused on and exemplarily described, for which instrumentation and support are commercially available and for which own research experience are given. One HPTLC-MS application is based on an interface using an elution head (high-performance thin-layer chromatography-electrospray ionization mass spectrometry, HPTLC-ESI-MS) the other two applications are using either laser light (HPTLC-MALDI-MS) or a gas beam for desorption (HPTLC-DART-MS). They all are soft ionization techniques however, when combined with analyzers suited for structure elucidation, like ion trap or tandem mass spectrometry (MS/MS), structural information is also available. 

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