Analysis Of Food Additives Research Articles

A thermo micro procedure for rapid extraction and direct application in thin-layer chromatography.

A simple thermo micro procedure is described for the separation of many substances from solid materials and the direct transfer of these substances to the starting point of a thin-layer chromatographic plate. The sample is introduced into a glass cartridge with a conical tip, and heated rapidly for a short time at a pre-set temperature. The emerging vapours are deposited as a spot on the thin-layer chromatographic plate, which is then chromatographed in the usual way. There are numerous variations of the standard procedure, thus extending the range of application, and this is demonstrated with examples from the fields of drug research, phytochemistry, analysis of food additives and residues, and from organic and inorganic chemistry.

Studies on Analysis of Food Additives (XVII)

Studies on Analysis of Food Additives (XVII)

Studies on Analysis of Food Additives (XVI)

Studies on Analysis of Food Additives (XVI)

Studies on Analysis of Food Additives (XIV)

Studies on Analysis of Food Additives (XIV)

Studies on Analysis of Food Additives (XV)

Several kinds of determination methods of diethylpyrocarbonate (DEPC) have been published, but most of them are indirect methods, for example, the neutralization titration method.In this paper, the new direct determination method is described. The principle of the method bases on the fact that DEPC is converted to phenylurethane on reacting with aniline, which is determined by gas chromatography. Chromosorb W containing DC 550 (10%) is suitable as the column and 2-ethoxynaphthalene or 1-methylnaphthalene as the internal standard substance.This method was applied to “Sake”, wine, beer and fruit juice, in which 100ppm of DEPC were added.The gas chromatogram was not interfered by the components contained in foods and the recovery was over 95%.The rate of decomposition of DEPC in the foods was about 90% after three hours at 20°C and almost 100% after 24 hours.

第7巻正誤表

第7巻正誤表

Studies on Analysis of Food Additives (VIII)

The existing method for determining nitrite ion in fish sausage, for example, themethod being included in “Standard Methods of Sanitary Inspection Guide” issued by the Ministry of Health and Welfare was studied.The authors clarified the following points through analytical experiments.1) The nitrite ion in a test solution prepared from fish sausage disappeared completely when the solution was distilled. Therefore, the test solution should be developed without distillation, though it is colored or turbid, and in this case, the test solution should be used as a control.2) The phosphate buffer solution (pH 7) as an extracting solvent for nitrite ion (NO2-) was more effective than water. Because the loss of the nitrite ion was less with the use of the buffer solution than water.3) Thirty minutes were quite enough to extract nitrite ion from fish sausage.

Studies on Analysis of Food Additives (XII)

The control standard method was applied to the assays for 2-(2-furyl)-3-(5-nitro-2-furyl)-acrylamide (abbreviated as furylfuramide) and nitrofurazone.The procedures are as follows:FURYLFURAMIDEReagent:Control standard solution: Weigh accurately about 0.1g of potassium bichromate, dissolve in 0.01N sulfuric acid and make exactly to 1000ml.Sample solution:Weigh accurately about 0.1g of furylfuramide, dissolve in 40ml of dimethylformamide and dilute with water exactly to 1000ml. Dilute 10ml of this solution with the mixture of 0.05M KH2PO4 solution and 0.05M Na2HPO4 solution (9:1, pH6.0) to 100ml. The volumetric flask used should be colored, because furylfuramide solution is very sensitive to light.Determination:Determine the absorbance of the control standard solution (As), at the wave length of absorption minimum (about 313mμ). At the same time determine the absorbance of the sample solution (A), at the wave length of absorption maximum (about 308mμ).Calculation:Content(%)=A/As×0.842×Weight of potassium bichromate(g)/Weight of furylfuramide(g)×100NITROFURAZONEReagent:Control standard solution: Weigh accurately about 0.1g of potassium bichromate, dissolve in 0.01N sulfuric acid and make exactly to 1000ml. Dilute 25ml of this solution with 0.01N sulfuric acid to 100ml.Sample solution:Weigh accurately about 0.1g of nitrofurazone, dissolve in 40ml of dimethylformamide and dilute with water exactly to 1000ml. Dilute 5ml of this solution with the mixture of 0.05M KH2PO4 solution (9:1, pH6.0) to 100ml. The volumetric flask used should be colored, because nitrofurazone solution is very sensitive to light.Determination:Determine the absorbance of the control standard solution (As), at the wave length of absorption maximum (about 257mμ). At the same time determine the absorbance of the sample solution (A), at the wave length of absorption maximum (about 261mμ).Calculation:Content(%)=A/As×0.947×Weight of potassium bichromate(g)/Weight of nitrofurazone(g)×100

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

Studies on Analysis of Food Additives (XIII)

Studies on Analysis of Food Additives (XIII)

Studies on Analysis of Food Additives (VII)

The diethyldithiocarbamate method of copper ion is generally used as the assay method of copper ion. However, the color obtained by this method is unstable.In this report, the experimental conditions of the colorimetric method are described, in which pyridine and ammonium thiocyanate are used as the reagents. The new method is more excellent than the diethyldithiocarbamate method in the following points.(1) Chloroform is very effective in case of extraction of the colored substance.(2) The colored chloroform solution (λmax. 407mμ) is stable through 24 hours.(3) The method is not interfered by the coexistence of most of cationsahd anions except ferrous ion. The interference of ferrous ion, however, is able to be avoided by the addition of potassium persuifate.(4) The method is able to be applied to the determination of copper in foods, drugs and water. For example, in case of water containing 1 ppm of copper ion, about 0.33 is obtained as the absorbance (the volume of the sample water: 200ml, the length of the cell: 10mm).

Studies on Analysis of Food Additives (VI)

Studies on Analysis of Food Additives (VI)

On the Analysis of Food Additives (V)

On the Analysis of Food Additives (V)

正誤表

正誤表

正誤表

正誤表

正誤表

正誤表

On the Analysis of Food Additives (III)

On the Analysis of Food Additives (III)

On the Analysis of Food Additives (IV)

On the Analysis of Food Additives (IV)

正誤表

正誤表

On the Analysis of Food Additives (II)

On the Analysis of Food Additives (II)