Colorant testing chromatography

IV as a cinerin-type compound, peak V as cinerin II, and peak VI as pyrethrin II. It is evident that peak IV also contains another component. The peaks beyond peak VI are known to be of the pyrethrin type as they respond to the color test. This gas chromatography pattern was obtained with a 6-foot lA -inch column packed with 20% SE-30 on 40-60-mesh Chromosorb P. Later work provided good resolution of the peaks with a 2-foot 4-inch column packed with 20% Dow-11 silicone oil on 45-60-mesh Chromosorb P. 

Two identification tests for oxytetracycline hydrochloride are given in the USP 28 [1], one being an ultraviolet absorption test and the other a color test. European Pharmacopoeia [2], British Pharmacopoeia (BP) 2003 [4], International Pharmacopoeia [5], and Pharmacopoeia of the People s Republic of China [6] described a thin-layer chromatography and color tests for identification of oxytetracycline hydrochloride and oxytetracycline dihydrate. For identification of oxytetracycline calcium, USP 28 [1] used Method II under identification of tetracycline <193>, whilst BP 2003 [4] described a TLC, color test, and calcium test as the method of identification. 

Seized samples of marijuana are analyzed in the laboratory using a color test, thin-layer chromatography, and a microscopic test. The Duquenois-Levine color test, although not specific for marijuana, is often used. Using the microscope one can see on the upper side of the marijuana leaf characteristic bear claw -shaped cystolithic hairs, which contain calcium carbonate. 

Cachia and his team (P) describe the column chromatographic separation of polyvinyl chloride plasticizers. The plasticization agent in the eluate was identified by infrared spectroscopy. These authors expressly state that chromatography is useful for separations only it is not intended to identify substances. However, they mention that spectroscopy, in the future, may be replaced by combining refractive index data with color tests. 

Carboxylic acids often have been identified by means of paper chromatography Clarke and Bazill (10) have extracted plasticizers from polyvinyl chloride first with ether and then with methanol. Subsequently the extracts were saponified with alcoholic potassium hydroxide, and the precipitated potassium salts were isolated and converted into free acids. These, in alcoholic solution, were then applied to paper and chromatographed ascendingly with a mixture of butanol, pyridine, water, and ammonia the migration period was about six hours. A number of additional color tests facilitated identification of unknown acids. 

Other ee assays have been described, although in several cases the actual degree of throughput was not specified [10]. These systems include assays based on color tests [8,46 - 48,60], IR-thermography [49,61], circular dichroism [62], fluorescence [63], and even special forms of gas chromatography [64], Moreover, optically active compounds capable of enantioselective recognition of chiral substrates can be used as... 

Adulteration of fats and oils is an old problem. Many older tests involved determination of physical properties such as refractive index, melting point, and viscosity. However, color tests were later used for this purpose. Thus, Baudonin reaction for sesame oil and the Halpben test for cottonseed oil have been noted. In both cases, a compound characteristic to an oil determines the presence of the oil. However, today such detections and quantitations are carried out with GC and HPLC procedures. Thus, cholesterol and phytosterols may be determined by gas chromatography for fingerprinting purposes however, fatty acid analysis might also be used for higher levels of contamination (31). Detailed discussion of issues related to oil authentication and adulteration has taken place (11). 

Drs. Moore and Stein of the Rockefeller Institute have studied the quantitative amino acid content of gramicidins A and B by starch chromatography. Figure 4 is an elution curve of gramicidin A. Here the concentration is estimated by the sensitive ninhydrm color test. 93% recovery of the nitrogen is accounted for. It has not proven possible... 

Screening tests, including thin layer chromatography (TLC), urine color tests, and the Guthrie microbiological test. (Details of these tests are given in a previous edition of this textbook.) ... 

In addition to melting point measurements, there are other methods to evaluate or prove the achieved progress in purification. These are gas chromatography, density measurements, or the different types of color tests. 

A color test utilizing isatin for piperidine and pyrrolidine alkaloids containing the structural unit — NH—CH2—CH2— has been described (53). Coniine and conhydrine give a positive test but pseudoconhydrine, which lacks the above feature, does not. The Conium alkaloids have been separated by gas-liquid chromatography (54). 

Clemo-McQuillen pycnometer, 49 color tests, 631, 649, 653 column chromatography. See also chromatography column elution, 94-95 column packing, 93-94 defined, 92 fraction collection, 95 materials, 92-93 sample application, 94 column holdup, 65 columns... 

Frequency-Pulsed Electron Capture Gas-Liquid Chromatography and the Tryptophan Color Test for Rapid Diagnosis of Tuberculous and Other Forms of Lumphpcytic Meningitis J. Clin. Microbiol. 12(2) 208-215 (1980) CA 93 234178m... 

Hexahydroxydiphenic acid in a bound form (3) is readily detected in a plant extract by an old but very distinctive color test - the Procter-Paessler reaction. Esters of type 3 react with nitrous acid to give a carmine or rose red, changing to brown-green, then purple, and finally indigo blue. The chemical basis of this reaction has not been discussed but it has been employed by Bate-Smith (6, 7) for the quantitative determination of 3 in plant extracts, and it forms the basis of a very useful spray reagent for the detection of 3 by paper chromatography (6, 7, 43). 

In the search for unknown drugs and/or pharmaceuticals in body fluids, a combined instrumental approach is especially helpful. Table III shows our extraction scheme. For drug analysis, steam distillation is usually omitted. Different extraction steps isolate the strongly acidic, weakly acidic, neutral, basic and amphoteric compounds in separate fractions. All are analyzed by UV-spectro-photometry, in organic solution and (with the exception of the neutral extract) also in water at 3 different pH-values. Thin- layer chromatography, color tests, IR- and fluorescence-spectrophotometry may yield additional information. Fractions of interest are analyzed by GC-MS. 

Color tests and fluorescence analysis give indications of which groups of compounds might be present in a lichen sample, while microcrystallization, chromatography, and lichen mass spectrometry lead to tentative identifications of the compounds. 

Specifications and Analytical Methods. Butanediol is specified as 99.5% minimum pure, determined by gas chromatography (gc), sohdifying at 19.6°C minimum. Moisture is 0.04% maximum, determined by Kad-Fischer analysis (dkecdy or of a toluene a2eotrope). The color is APHA 5 maximum, and the Hardy color (polyester test) is APHA 200 maximum. The carbonyl number is 0.5 mg KOH/g maximum the acetal content can also be measured dkecdy by gc. 

Hydantoin itself can be detected ia small concentrations ia the presence of other NH-containing compounds by paper chromatography followed by detection with a mercury acetate—diphenylcarba2one spray reagent. A variety of analytical reactions has been developed for 5,5-disubstituted hydantoias, due to their medicinal iaterest. These reactions are best exemplified by reference to the assays used for 5,5-diphenylhydantoiQ (73—78), most of which are based on their cycHc ureide stmcture. Identity tests iaclude the foUowiag (/) the Zwikker reaction, consisting of the formation of a colored complex on treatment with cobalt(II) salts ia the presence of an amine (2) formation of colored copper complexes and (3) precipitation on addition of silver(I) species, due to formation of iasoluble salts at N. ... 

Analytical and Test Methods. o-Nitrotoluene can be analyzed for purity and isomer content by infrared spectroscopy with an accuracy of about 1%. -Nitrotoluene content can be estimated by the decomposition of the isomeric toluene diazonium chlorides because the ortho and meta isomers decompose more readily than the para isomer. A colorimetric method for determining the content of the various isomers is based on the color which forms when the mononitrotoluenes are dissolved in sulfuric acid (45). From the absorption of the sulfuric acid solution at 436 and 305 nm, the ortho and para isomer content can be deterrnined, and the meta isomer can be obtained by difference. However, this and other colorimetric methods are subject to possible interferences from other aromatic nitro compounds. A titrimetric method, based on the reduction of the nitro group with titanium(III) sulfate or chloride, can be used to determine mononitrotoluenes (32). Chromatographic methods, eg, gas chromatography or high pressure Hquid chromatography, are well suited for the deterrnination of mononitrotoluenes as well as its individual isomers. Freezing points are used commonly as indicators of purity of the various isomers. 

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