Al2O3 Column Research Articles

Studies on Analysis of Food Additives (X)

The colorimetric determination method of 2- (2-furyl) -3- (5-nitro-2-furyl) -acrylamide (abbreviated name: furylfuramide), the new preservative adopted as a food additive in Japan in 1965, in foods was tried and succeeded. As the sample, the fish sausage containing furylfuramide at the concentration of 20ppm was taken up. The principle of the determination bases on the fact that furylfuramide liberates nitrite ion on warming with sodium hydroxide in methanol or water, the color of which is developed by the usual way. The details of the procedure are as follows.(1) Weigh 10g of the sample containing furylfuramide. Add 5-10g of sodium chloride, 15-25ml of 5% m-phosphoric acid and 20ml (or 30ml) of the mixed solution of toluene and butyl acetate (1: 1), then homogenize and centrifuze.(2) Pour 10ml (or 15ml) of toluene and butyl acetate layer on Al2O3 column (6cm length and 1.5cm diameter). Wash with 20ml of n-hexane and then 20ml of ethyl ether.(3) Elute with 40ml of methanol (use 10ml of methanol each time and repeat four times). Take off about 4ml of the first eluate.(4) Collect 35-40ml of the eluate in the 50-ml brown-colored volumetric flask.(5) Add 1ml of 20% sodium hydroxide solution and warm at 50-55° in water bath for 50 minutes, then cool in ice water.(6) Add 2ml of sulfanilamide solution (2g of sulfanilamide are dissolved in 100ml of 20% hydrochloric acid) and stand for 15 minutes in ice water, then add 1ml of 0.1% N-naphthyl ethylenediamine dihydrochloride solution and stand for 30 minutes at room temperature.(7) Dilute the colored solution exactly to 50ml with methanol and determine the absorbance at 545mμ. Using these absorbances obtained calculate the concentration of furylfuramide in the sample.Concentration (ppm) =200×A/As×1/Weight of sample (g)A: Absorbance obtained from the sampleAs: Absorbance obtained from 5ppm furylfuramide standard solution

�ber das Vorkommen von Katecholaminen und von 3,4-Dihydroxyphenylalanin (Dopa) im Auge

1. The occurrence and distribution of catecholamines in the ocular tissue of the calf has been investigated by a fluorimetric method. 2. In the lens, in the vitreous humour and in the retina (without the pigment-epithelium) no significant amounts of noradrenaline have been detected. In the chorioideal layer, isolated together with the retinal pigment-epithelium, noradrenaline was found in concentrations from 0.01 to 0.15 μg/g wet tissue. The noradrenaline concentration in the iris was in the range of 0.19–0.66 μg/g wet tissue. 3. The adrenaline concentration, as estimated in one sample of iris tissue, was as low as 0.05 μg/g. 4. Another fluorescent catechol compound was found in the iris as well as in the chorioideal layer (isolated together with the retinal pigment-epithelium). 5. This catechol compound was found to be 3.4-dihydroxyphenylalanine (dopa), as identified by twodimensional paper chromatography, separation on ion-exchange and Al2O3 columns, colour reactions, fluorescent behaviour and by enzymatic decarboxylation to dopamine. 6. The dopa concentration in these tissues was in the range of 1.06 to 4.34 μg/g wet tissue, or even higher, as might be concluded from the experimental data. 7. The occurrence of dopa in the ocular tissue might possibly be connected with the metabolism of melanin.

On the components of soil humic acids (part 8) the oxidative decomposition by alkaline potassium permanganate and nitric acid

Abstract As for the reactions by oxidizing agents of humic acids and for the products obtained by the said reactions, a number of investigations (1) have been made with regard to the study of the chemical structure of humic acids and with the use of the products of decomposition. The authors (2) have observed that A-or B-types of soil humic acids could be separated into three or four fundamental composing fractions by using Al2O3 column.