Phosphomolybdic acid reagent

The phosphomolybdic acid reagent can be employed on silica gel, aluminium oxide, polyamide, RP-2, RP-18 and cellulose phases and also on silver nitrate-impregnated silica gel [13]. 

The neocuproine method for the measurement of the cuprous oxide is more sensitive than the phosphomolybdic acid reagent and uses 2,9-dimethyl-1, 10-phenanthroline hydrochloride (neocuproine), which produces a stable colour and is specific for cuprous ions. 

ACS reagent grade hexanes and ethyl acetate were obtained from Aldrich Chemical Company, Inc. Thin layer chromatography was performed on Silica Gel 60 F-254 precoated plates. Chromatograms were visualized with phosphomolybdic acid reagent from Aldrich Chemical Company, Inc. 

Phosphomolybdic acid reagent (H3[PMol2O4.0]) molybdenum blue is produced by antimony(III) salts. Of the ions in Group II, only tin(II) interferes with the test. The test solution may consist of the filtered solution obtained by treating the Group IIB precipitate with hydrochloric acid the antimony is present as.Sb3+ and the tin as Sn4+, which has no effect upon the reagent. 

Place a drop of the test solution upon drop-reaction paper which has been impregnated with the phosphomolybdic acid reagent and hold the paper in steam. A blue colouration appears within a few minutes. 

A mixture of nicotinic acid, nicotinamide, trigonelline and tryptophan can be separated chromatographicaUy, using as solvent a 5 i mixture of n-butanol and concentrated hydrochloric acid, saturated with water. Tryptophan is revealed by ninhydrin, while nicotinic acid, nicotinamide and trigonelline are detected with phosphomolybdic acid reagent and the color developed with stannous chloride, which reduces the phosphomolybdic acid to give a blue spot. The Rf values for the butanol-HCl solvent are nicotinic acid, 0.37 nicotinamide, 0.28 trigonelline, 0.38 and tryptophan, 0.62. 

Fatty acid diester of poIy(ethylene glycol). The enzymatic esterification was performed in bulk at 50-60°C under vacuum and completed in 8-48 hours. The enzyme use level was 0.1-0.5% based on the substrate. The acid numbers of the ester products depended on the enzyme type, the enzyme use level and the reaction temperature. Progress of each reaction was monitored by TLC analysis (eluted with EtOAc/Hex, 1 3 detected by the phosphomolybdic acid reagent), which showed the disappearance of fatty acid (Rf = 0.4) and the emergence of the PEG ester (Rf= 0-0.1). The enzyme was recovered by filtration. The product was obtained as a yellowish liquid and analyzed without further purification. All product structures were confirmed by and C-NMR analysis. 

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