Visualization reagents

Location of Separated Zones by Use of Visualization Reagents, UV Absorbance on Layers Containing a Fluorescent Indicator, and Densitometry... 

Thin-layer Fluorescence-indicator-impregnated Visualization reagents Charring with acid and heat... 

Caution Spraying thin-layer plates with visualization reagents should always be done in a functioning hood. These reagents may be caustic and toxic, as is the case with sulfuric acid. 

Mosley R.T., Culberson J.C., Kraker B., Feuston B.P., Sheridan R.P., Conway J.F., Forbes J.K., Chakravorty S.J., Kearsley S.K., Reagent selector using synthon analysis to visualize reagent properties and assist in basis set selection. J. Chem. Inf. Model. 2005, 45, 1439-1446. 

Char Various other visualization reagents can be used ni... 

A number of spray reagents are available for visualization of nitrogenous compounds. Ninhydrin is useful for primary and secondary amines [54] and acidified iodoplatinate reacts with primary, secondary, tertiary amines, and quaternary ammonium compounds. Visualization reagents used for detection of specific drugs are listed in the last part of this book. Quantification is possible for the above detection procedures if the formed products are stable and where interferences are absent. 

For qualitative identification, the Rf values are calculated from the distances measured on the plate or paper. Alternatively, the distances migrated can be measured relative to a standard run on the same plate, which usually is more reproducible. The colors caused by the visualizing reagents can also be used for identification sometimes. 

There are two principle problems. The first is lack of resolution, for example, in the methanol/ammonia system, cocaine/procaine and ecgo-nine methyl ester/lidocaine are not well resolved and yet may occur together in the mixture. A further difficulty is added by the lack of specificity of the visualization reagents. None of the reagents used here are specific to this group of compounds. 

By comparison of the Rf data and the colours observed under different light conditions and with different visualization reagents, the compounds thought to be present in the mixture can be determined and standard mixes prepared for GC-MS analysis. In addition, it may be possible to make comparisons between samples. 

The use of ninhydrin as a reagent provides a rapid and sensitive method for the detection of the primary amine groups in these alkaloids. Such amino groups react with this visualization reagent to form an iso-indole species, known as Ruhmann s purple . 

Phenolic Drugs, New Visualizing Reagents for Detection in TLC Alina Pyka... 

Find the locations of the separated bands by visible, ultraviolet (UV), or UV quenching. Alternatively, cut a Vi6-in. vertical slice off the tube. Spray the exposed area with an appropriate visualization reagent and align with the untreated column to identify (mark) the separated bands. 

For identification in qualitative thin layer chromatography, a great number of visualization reagents are used. If compounds are not colored, a UV lamp may be used to visualize the plates. The quantitative determination of sample components is performed according to the following ... 

The visualizing effect depends on the chemical stmcture of the visualizing reagent, the structure of the substance detected, as well as the chromatographic adsorbent applied. 

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