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Orcinol

Those colorimetric methods developed at this time and found to be suitably sensitive and specific are the orcinol and resorcinol methods (see II. 1 below) and the periodic acid/thiobarbituric acid assay (see II. 2). These methods together with a recently introduced assay using methyl-3-benzothiazolinone-2-hydrazone and fluorimetric methods (II. 3 and II. 4, respectively) form the basis of currently used techniques. [Pg.78]

As the assay does not discriminate between bound and free sialic acids, it is widely used to monitor the presence of sialic acids in either form during fractionation of biological material. Interference by other monosaccharides. [Pg.78]

Compounds Diphenol assays Periodic acid/thiobarbituric acid assay  [Pg.79]

Sodium (23 g., or 1.0 gram atom) is added in small portions to 300 ml. of absolute ethanol (p. 142), and to the resulting solution is added 140 g. (1.08 moles) of ethyl acetoacetate [Org. Syntheses Coll. Vol. 1, 235 (1941)]. One hundred and fifteen grams (1.0 mole) of ethyl crotonate (p. 148) is added slowly, and the resulting mixture is heated under reflux for 5 hours after completion of the addition. Cooling to 0° precipitates the solid sodio derivative of 4-carbethoxy-5-methyl-l,3-cyclohexadione (180 g. or 82%), and this is removed by filtration and acidified with acetic acid, and the ester is separated. [Pg.241]

A solution of 140 g. (0.71 mole) of the above ester in 450 ml. of acetic acid is treated with a solution of 105 ml. of bromine in acetic acid, the temperature of the reaction mixture being held around 40° during this operation. The reaction mixture is stirred overnight, and the precipitated ethyl 2,4-dibromoorcinol-6-carboxylate is filtered and recrystallized from ethanol. The yield is 195 g. (80%), and the product melts at 144°. [Pg.241]

The dibromo compound is dehalogenated by agitating under a hydrogen atmosphere a mixture of 80 g. (0.23 mole) of the dibromo compound, 700 ml. of N aqueous sodium hydroxide solution, and a catalyst consisting of 2% palladium on polyvinyl alcohol prepared from 0.5 g. of palladium chloride (p. 244). To the resulting mixture is added 120 g. of sodium chloride, and the precipitated catalyst is removed by filtration. The filtrate is acidified and extracted with chloroform. Removal of the chloroform by distillation gives 35 g. (80%) of ethyl orcinol-6-carboxylate, m.p. 132-133°. [Pg.241]

A mixture of 17 g. (0.87 mole) of the above ester, 40 g. of sodium hydroxide, and 150 ml. of water is heated to 90° for 2 hours. The mixture is acidified, heated to boiling for 3 minutes, cooled, and extracted with ether. Distillation of the ethereal extract gives 8.6 g. (80%) of orcinol boiling at 147°/5 mm., m.p. 106-108°. [Pg.241]


Bial s reagent (for pentoses) dissolve 1 g of orcinol in 500 mL of 30% HCl to which 30 drops of a 10% ferric chloride solution have been added. [Pg.1188]

Oakmoss. Extracts of oakmoss are extensively used in perfumery to furnisli parts of the notes of the fougnre or chypre type. The first step in the preparation of an oakmoss extract is treatment of the Hchen Evemiaprunastri (L.) Ach., collected from oak trees mainly in southern and central Europe, with a hydrocarbon solvent to obtain a concrete. The concrete is then further processed by solvent extraction or distillation to more usable products, of which absolutes are the most versatile for perfumery use. A definitive analysis of oakmoss volatiles was performed in 1975 (52). The principal constituents of a Yugoslav oakmoss are shown in Table 15 (53). A number of phenoHc compounds are responsible for the total odor impression. Of these, methyl P-orcinol carboxylate is the most characteristic of oakmoss. [Pg.314]

Fe7-ric chloride reaclion.—Dissolve a drop of the free phenol in water and add a drop of ueutral ferric chloride. A green (catechol), blue (orcinol, pyiogallol) or purple (phenol, resorcinol) colouration is produced, which is often destroyed by acid or alkali. Quinol is o.xidised to quinone, and turns biown (p. 193). The naphthols give precipitates of dinaphthol (p. 220). [Pg.329]

Synthesis of the remaining half of the molecule starts with the formation of the monomethyl ether (9) from orcinol (8). The carbon atom that is to serve as the bridge is introduced as an aldehyde by formylation with zinc cyanide and hydrochloric acid (10). The phenol is then protected as the acetate. Successive oxidation and treatment with thionyl chloride affords the protected acid chloride (11). Acylation of the free phenol group in 7 by means of 11 affords the ester, 12. The ester is then rearranged by an ortho-Fries reaction (catalyzed by either titanium... [Pg.314]

Discussion. Minute amounts of beryllium may be readily determined spectrophotometrically by reaction under alkaline conditions with 4-nitrobenzeneazo-orcinol. The reagent is yellow in a basic medium in the presence of beryllium the colour changes to reddish-brown. The zone of optimum alkalinity is rather critical and narrow buffering with boric acid increases the reproducibility. Aluminium, up to about 240 mg per 25 mL, has little influence provided an excess of 1 mole of sodium hydroxide is added for each mole of aluminium present. Other elements which might interfere are removed by preliminary treatment with sodium hydroxide solution, but the possible co-precipitation of beryllium must be considered. Zinc interferes very slightly but can be removed by precipitation as sulphide. Copper interferes seriously, even in such small amounts as are soluble in sodium hydroxide solution. The interference of small amounts of copper, nickel, iron and calcium can be prevented by complexing with EDTA and triethanolamine. [Pg.683]

Note. Prepare the dye solution by stirring 0.025 g of 4-nitrobenzeneazo-orcinol mechanically for several hours with 0.1 M sodium hydroxide filter before use. [Pg.684]

Protein concentration can be determined by using method of Bradford,9 which utilises Pierce reagent 23200 (Pierce Chemical Company, Rockford, IL, USA) in combination with an acidic Coomassie Brilliant Blue G-20 solution to absorb at 595 nm when reagent binds to the protein. A 20 mg/1 bovine serum albumin (Pierce Chemical) solution was used as the standard. Starch concentration was measured by the orcinol method4,9-11 using synthetic starch as the reference. A yellow to orange colour is obtained and measured at 420 nm when orcinol reacts with carbohydrates. Absorbance is determined by spectrometry. [Pg.336]

Chromatographic characterisation of hydrolysis products Hydrolysis products from sodium polypectate were analysed by thin-layer chromatography on silica gel G-60, using ethyl acetate / acetic acid / formic acid / water (9 3 1 4, by volume) as the mobile phase system. Sugars were detected with 0,2% orcinol in sulphuric add-methanol (10 90ml) [14]. [Pg.788]

Spray a solntion of 0.5% of a-naphthol in 100-ml methanol (1 1) allow to air-dry and spray concentrated H2SO4 (95 5) heat at 120°C nntil color is maximal Dissolve 20-mg orcinol in 100 ml of 75% H2SO4. Spray plates lightly with the reagent, heat at 100°C for 15 min. [Pg.317]

Amperometric parameters have been studied and optimized for sugar separations.57236 The orcinol reaction has also been used as a post-column detection system for sugars.237... [Pg.251]

CMC-2, HW-55(S) Fractogel TSK E. Merck, Darmstadt, pH 5, 0.02% NaN3 0.05 MNa2S04,0.05 M NaAcetate Orcinol-H2S04, post-column with colorimetric detection (X= 420 nm)... [Pg.356]

Sorensen and Haugaard147 showed that by a suitable fractionation of crystalline albumin there could be obtained a series of fractions which, although crystalline, varied widely in their properties, particularly in regard to their carbohydrate contents. The most soluble fraction contained about fifty times as much carbohydrate as the least soluble. In most of these studies the carbohydrates were estimated by modification of the orcinol colorimetric method of Tillmans and Philipi181 which could... [Pg.211]

Purification of the conjugates may be done by reverse phase HPLC separation. Dry the reaction solution under a nitrogen stream and reconstitute in a minimum volume of acetonitrile/water (1 1, v/v). Apply the sample to a 5 pm Cig-silica HPLC column (250 X 4.6 mm, Nucleosil). Elute with a gradient of water to acetonitrile at a flow rate of 1 ml/minute over a time course of 30 minutes. Free BNAH and BNAH-glycan derivatives can be monitored by absorbance at 275 nm. The conjugate peak also will be positive for carbohydrate by reaction with orcinol, which can be detected by spray after spotting a small eluted sample on a TLC plate. [Pg.543]

Some comparative studies of these methods have been made anthrone and N-ethylcarbazole were compared by Lewis and Rakestraw [153] and by Collier [155], and anthrone, phenol, orcinol and N-ethylcarbazole and L-tryp-tophan were examined by Josefsson et al. [156]. In general, the comparative studies show anthrone to be more reliable than N-clhylcarbazole, although somewhat less sensitive. However, Josefsson and co-workers [154] found that of the five methods, the tryptophan method gave the best results when adapted to automatic analysis, and was capable of analysis at concentrations of interest in seawater analysis, i.e., xg/l levels. [Pg.397]

Larsson and Degens [171] devised an automated system for determining carbohydrates in biological samples using partition chromatography for the separation and the orcinol colorimetric method for the final analysis. Later versions of this kind of autoanalyser, using tetrazolium blue or a Cu1 complex of bicinchoninate for the final measurement, have been reported [172]. [Pg.399]

In 1964, Netrawali et al.66 described fluorescence measurements of calcium leucovorin in NaHC03 solution after paper chromatography and reaction with acidic orcinol. The gray-blue fluorescent species formed on the developed paper-gram was very sensitive for leucovorin, showing a detection limit of 0.1 yg. In the eluting solution, however, the required concentration increased to 0.5 pg. Recovery by this method was 100 15%, and results obtained from fluorescence were lower by 10 to 20% than those obtained by microbiological methods. [Pg.339]

Thin-layer chromatography has been used by Foppiano and Brown229 to assay the total neomycin B and C content of neomycin sulphate. The neomycin zone was scraped off the plate and reacted with orcinol/ferric chloride reagent, the absorbance of the resulting colour being measured at 665nm. By this procedure a precision of - 2% was achieved. [Pg.464]


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