Thin layer chromatography and liquid

Analysis. Dilute aqueous solutions of hydroxyhydroquinone turn blue-green temporarily when mixed with ferric chloride. The solutions darken upon addition of small amounts, and turn red with additions of larger amounts of sodium carbonate. Derivatives used for identification are the picrate, which forms orange-red needles (mp of 96°C), and the triacetate (mp 96—97°C). Thin-layer chromatography and liquid chromatography are well suited for the qualitative and quantitative estimation of hydroxyhydroquinone (93,94). 

Sherma, J. Comparison of thin layer chromatography and liquid chromatography. J. Assoc. Off Anal. Chem. 1991, 74, 435-437. 

Experimental and theoretical studies of the separation of 1,7- and 1,10-phenanthrolines and some substituted derivatives in linear elution adsorption chromatography,thin-layer chromatography, " and liquid-liquid partition chromatography have been described. 

Egli, R. A., and Keller, S. (1984). Comparison of silica-gel and reversed-phase thin-layer chromatography and liquid chromatography in the testing of drugs. J. Chromatogr. 291 249-256. 

The active drug and metabolites can be detected from the urine by thin-layer chromatography, gas-liquid chromatography, or gas chromatography-mass spectrometry. However, assays are available only at specialized centers. Treatment of acute intoxication with mescaline is virtually identical to the treatment outlined for LSD intoxication. DOM-induced vasospasm responds well to intra-arterial tolazohne or sodium nitroprusside. Major life-threatening complications of hallucinogenic amphetamine derivatives include hyperthermia, hypertension, convulsions, cardiovascular collapse, and self-inflicted trauma. 

The identification of the target colorant is done directly by UV-Vis spectrometry (if the colorant is unique) or by a previous separation from a mixture. The most available techniques are planar chromatography (paper chromatography and thin layer chromatography) and, especially, high performance liquid chromatography... 

Cinnamyl anthranilate can be assayed by a method based on ester hydrolysis. Bulk samples of food-grade cinnamyl anthranilate have been analysed for purity by thin-layer chromatography and high-performance liquid chromatography. A method has been described for determining the content of this compound in food products by steam distillation followed by paper chromatography and examination under ultraviolet light it has a limit of detection of 1 pg (lARC, 1983). 

Gas-Liquid Chromatography. Gas-liquid chromatography (GLC) affords both a qualitative and, if adequate internal standards are used, a quantitative analysis of the products of lipolysis. It is necessary, however, first to isolate the acids by a suitable method and then to inject them as free acids or as esters. The partial glycerides can be isolated by thin-layer chromatography and can also be determined by GLC of suitable derivatives. The acid(s) remaining in the partial glycerides can be identified readily by GLC following transesterification. Jensen and co-workers have utilized these techniques in their studies of lipase specificity (Jensen et al 1964). 

Techniques such as mono- and bidimensional thin-layer chromatography and high-voltage electrophoresis have been used in peptide separations for many years. However, the versatility, short analysis times, and high resolution of high-performance liquid chromatography (HPLC), coupled with the possibility of automating the analysis process, make this analysis technique the method of choice in peptide analyses at the present time (l-6a). 

A Ibe, K Saito, M Nakazato, Y Kikuchi, K Fujinuma, Y Naoi, T Nishima. Detection and determination of aspartame in foods by thin layer chromatography and high performance liquid chromatography. J FoodHyg Soc Jpn 26(1) 1-6, 1985. 

The scope of this review is limited to the hop-borne a- and /3-acids and to products derived from them that have appreciable commercial relevance. Thus, the liquid chromatography of the iso-a-acids and their chemically modified counterparts as well as of the hulupones will be considered. By far the major focus here will be HPLC analyses, but other methodologies that have been applied (countercurrent distribution, gas chromatography, supercritical-fluid chromatography, thin-layer chromatography, and micellar electrokinetic chromatography) will also be briefly considered. 

Liquid/Solid Chromatography (LSC) is adsorption chromatography. Adsorbents such as alumina and silica gel are packed in a column and the sample components are displaced by a mobile phase. Thin layer chromatography and most open column chromatography are considered liquid/solid chromatography. 

Sherma, J (1986). Determination of triazine and chlorophenoxy acid herbicides in natural water samples by solid phase extraction and quantitative thin layer chromatography. J. Liquid Chromatog., 9(16) 3433-3438. 

Steinbrech, B. (1987) Thin layer chromatography and high pressure liquid chromatography of metal chelates./. Liquid Chromatogr., 10, 1-13. 

Table 14.2 Comparison between algal pigment analyses carried out by the high performance liquid chromatographic method, by reflectometric thin layer chromatography, and by the polychromatic method...

Waggon and Jehle [121,122] have reported on the quantitative detection of triphenyl and tri-, di-, and monobutyltin species in aqueous solution by a combination of liquid-liquid extraction, thin layer chromatography and anodic stripping voltammetry. 

Basically the techniques can be divided in three categories, those applicable only to relatively volatile substances such as gas chromatography, those applicable to non volatile substances such as thin layer chromatography and those applicable to both volatile and non volatile such as high performance liquid chromatography and other techniques and ion chromatography. 

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