Technique
Thin-Layer Chromatography as an Analytical Tool


Qualitative Analysis


Quantitative Analysis





Thin-Layer Chromatography as a Preparative Tool

Thin-layer chromatography of lipids

Synthesis and properties of glycerides

Chlorophylls are the green pigments in plants some of which, and perhaps all, participate in photosynthesis. An understanding of their nature, genesis, transformation, and function in plants requires that they and their near chemical relatives be recognized qualitatively and oftentimes be determined quantitatively. In addition to the use of analytical procedures for the identification and determination of the chlorophylls as participants in plant physiological processes, these methods may be used in various other fields of science and technology some of which are genetics, plant nutrition, certain aspects of pure chemistry, crop production of land and sea, medicine, pharmaceuticals, food technology, and paleontology.

Chlorophylls: Analysis in Plant Materials

Publisher Summary This chapter discusses the quantitative determination of carotenoids in photosynthetic tissues. A useful separation of carotenoid pigments into nonpolar carotenes and carotenoid esters in one group, and polar xanthophylls (containing hydroxyl groups) in the other may be accomplished by partitioning the pigments between petroleum ether and aqueous methanol. This can be done by dissolving the extract in aqueous methanol in a separatory funnel and adding an equal amount of petroleum ether. In cases where the carotenoid components are stable toward alkali, it is advantageous to include saponification in the isolation procedure for removing chlorophyll and other saponifiable matter. The pigment is taken to dryness (oil pump); all acetone must be removed from the extract to avoid base-catalyzed formation of condensation products of acetone. The residue is dissolved in a small volume of ether, and the same volume of 10% methanolic KOH solution is added. The approximate content of total carotenoids in an extract may be determined by measuring the optical density of a sample suitably diluted.

[56] Quantitative determination of carotenoids in photosynthetic tissues

The scintillation counting behavior of a group of fifty‐five pure crystalline organic compounds has been extensively studied. The data obtained have been analyzed with the goal of developing a better understanding of the scintillation process and of scintillator behavior.The materials were carefully purified, and massive crystals were grown. Relative scintillation average‐pulse‐height efficiencies at 30°C and —70°C for cobalt‐60 gamma‐ray excitation, gamma‐ray excited scintillation decay times, and 2537 A ultraviolet‐excited reflection and transmission photofluorescence spectra have been determined. A few solutions were also studied for comparison purposes. The purification and properties of the different materials are discussed in detail.The experimental data have been analyzed on the basis of Birks' photon cascade theory of the scintillation process. The ratio of the scintillation efficiency to the integrated photofluorescence intensity is shown to be a measure of Birks' primary photon production effici...

Harold H. Strain

Papers

Chromatographic adsorption analysis

Chromatographic Adsorption Analysis