Search

A new solvent system was given for the chromatography of food preservatives; benzoic acid, salicylic acid, p-hydroxybenzoic acid and it's esters, p-chlorobenzoic acid, sorbic acid, resorcinol and β-naphtol with the ascending method on Toyo Roshi No. 50 paper at 20-25°. Cyclohexanol-ammonium carbonate buffer gave results in 30 hours. Spots were detected by absorption when the paper was examined in ultraviolet light and with color reagcnts of the methyl red or diazo spray reagent. Rf values for this solvent were listed for these substances. Each substance was separated except in the case of mixture of benzoic acid and sorbic acid. However in this case, these two substances were identified by measuring spectrophotometrically the alcohol solution extracted from the part containing the substances on paper chromatogram.Horizontal paper electrophoresis on Toyo Roshi No. 51 paper for 1.5-2 hours at 20V per cm with buffer consisted of dimethylformamide, pyridine, acetic acid and water (pH 5.6) or of butanol, ammonia, acetic acid and water (pH 5.0) was useful. MNC (the ratio of the migration of the substances of New Coccine) and colors given with the methyl red, FeCl3 and diazo spray reagents were tabulated adding dehydroacetic acid to above substances. Data was also given for citric acid and tartaric acid.Sake (Japanese wine), soy etc., was acidified with HCl, extracted with ether, purified as ammonium-salts and submitted to paper chromatography and paper electrophoresis with similar technique.

A method for the detection of food preservatives (benzoic acid, salicylic acid, methyl, ethyl, propyl and butyl esters of p-hydroxybenzoic acid, sorbic acid and dehydroacetic acid) is described.The food preservatives can be isolated from a food by steam distillation and further purified by extraction procedures of the distillate. The food preservatives are then separated by thin-layer chromatography on polyamide with the following solvent systems, (a) n-hexane·acetic acid (20: 0.7), (b) benzene·acetic acid (20: 0.5), (c) benzene·methyl alcohol·acetic acid (20: 0.2: 0.5) and (d) benzene·methyl alcohol·acetic acid (20: 0.5: 0.3). The solvent system (a) is suitable for the separation of dehydroacetic acid, benzoic acid and sorbic acid, (b) for the separation of the others except dehydroacetic acid, (c) for the separation of the esters of p-hydroxybenzoic acid and (d) for the separation of the esters in the presence of salicylic acid. And the thin-layer chromatography is also applied to the separation of p-hydroxybenzoic acid.

The rapid and simple procedure modified from A. O. A. C. method was studied for the determination of total solids in milk for rutin work. The special dish was made of 0.02mm thin alminium foil and it was 35mm in diameter and 8mm in depth. To obtain 1.00g of sample, we made specified Ostward's pipettes which was enable to deriver 0.98ml of water per ca. 20 seconds at 20°C. Add 1.00g of well mixed milk sample (25°C) to the taxed dish, and dried the dish over a boiling water bath about 15min., and then at 98-100°C for 3 hours in a steam or an electric oven. There was no significant difference between the A. O. A. C. method and this modified method.