Orcinol reagent

One-dimensional TLC of native urine is done on silica gel plates with development in two solvent systems. Oligosaccharides are visualised by spraying with orcinol reagent followed by heating at 100°C and examination by transparency. 

Glycolipid 11, Table 1 (2) glycolipid 9, Table 11 (3) glycolipid 10, Table I. Solvent system chloroform/ methanol/ water (60/ 35/8, v/v/v). Visualization orcinol reagent. (26)... 

Fucolipid 19, Table I (2) fucolipid 20, Table I (3), jucolipid 21, Table I (4) fuco-lipid 22, Table 1. Solvent system chloroform/acetone/methanol/ water (52/40/00/4, by volume), plate A 1,2-dichloroethane/methanol/water (80/25/2, v/v/vj, plate B 1,2-dichloroethane/acetone/methanol/water (50/40/10/4, by volume), plate C. Visualization orcinol reagent. (52)... 

The original orcinol assay has been modified to improve its selectivity toward RNA over DNA and sugars. The improved method21 uses a 1.0-mL RNA sample incubated 24 h at 40 °C with 4.0 mL of 85% sulfuric acid prior to addition of the orcinol reagent (containing no Fe3+). Under these conditions, colorimetric measurements are made at 500 nm, where products formed by the reaction of levulinic acid (from DNA) with orcinol do not absorb. Proteins (e.g., BSA) do not interfere, and the method is sixfold more selective to RNA over DNA than the original orcinol assay. 

Fig. 4.6. Anion-exchange chromatography of carbohydrates as their borate complexes. Chromatographic conditions column, Aminex A-28 10 /im (50x0.3 cm I.D.) mobile phase, gradient of 40 ml of 0.124 M borate, pH 7.0 to 40 ml of 0.58 M borate, pH 10.0 flow rate, 10 ml/h temperature, 55°C detection, orcinol reagent reacted at 100°C for 20 min and measured by UV at 420 nm. Reproduced from Morrison et al. (1976), with...

The lipids were separated on a high-performance thin-layer chromatography (HPTLC) plate. The developing solvent was a mixture of chloroform, methanol, and 0.2% aqueous CaCl2. Orcinol reagent and Dittmer s reagent were used to detect glycolipids and phospholipids. 

Measuring the rate of disappearance of ribose-5-phosphate in the first reaction with orcinol reagent (i.e. Bial s test, q.v.). 

Fig. 5. Thin-layer chromatogram of the deacylated polar mycosides C from the 31 serovars of the MAIS complex. (Silicagel plate, developed mth CHCI3-CH3OH-H2O 65 25 4 lv/v/v and detected by orcinol reagent.) (From 204)...

Colominic acid is an acidic aminopolysaccharide elaborated in the culture medium of Escherichia coU K235 from which it can be isolated by alternate dialysis and lyophilization followed by fractional precipitation with aqueous ethanol and ammonium sulphate. Pure preparations ([a] —50.5° 2° in water) showed a single peak (mobility —ii.i-io- cm /volt.sec) when subjected to electrophoretic analysis in o.i M borate buffer pH 9.2. It was degraded by acid with formation of humin and when heated in o.i iV alkali gave a product with A 260 m/z in the ultraviolet. It reacted both with Ehrlich s reagent 53om )and Bial s orcinol reagent 540 m ). 

Soon afterward, Blix (1938) demonstrated that this carbohydrate from submaxillary mucin generated a purple chromophore with Bial s orcinol reagent that had the same absorption maximum as that reported... 

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