Anhydrous Na2SO4 Research Articles

Studies on Secondary Amines in Foods

A modified Cu-dithiocarbamate method was devised for determining secondary amines in foods. Procedure is as follows: A 5ml of trichloroacetic acid (TCA) extract of food sample and 1ml of 2% TCA solution are taken into a 50ml separatory funnel to which are added 10ml of 5% CS2-chloroform and 0.2ml of the alkali reagent, and the funnel is shaken vigorously by a mechanical shaker for 2 minutes. Then 1ml of the Cu-reagent is added to the funnel and it is shaken vigorously for 1 minute. Immediately after shaking, 1ml of 30% acetic acid solution is added to the reaction mixture, then the funnel is shaken for a few seconds. The lower layer (CHCl3) in the funnel is separated in a test tube to which 0.4g of anhydrous Na2SO4 is added to remove moisture. The color intensity of the CHCl3 solution is determined at 435mμ by a spectrophotometer. Similar test is conducted with the test solution containing 5μg of standard dimethylamine-nitrogen (DMA-N) (1ml of 5μg/ml of DMA-N is added to 5ml of the test solution). The concentration of secondary amines may be calculated by the following equation:where, C; concentration of secondary amine-N (DMA-N equivalent, p. p. m.)A1; absorbance obtained with a test solutionA2; absorbance obtained with the test solution containing 5μg of standard DMA-N*; amount of standard DMA-N added (5μg)The recovery of DMA-N added to food samples is approximately 97%.

Optically active isomers of the genus Pinus and their application in chemosystematic

Aim. The aim of this work was the possibility of using the composition of essential oils enantiomers as chemomarkers for the genus Pinus. Methods. The plant materials were subjected to hydrodistillation in a Ginsburg type apparatus (0.2 kg each loading) for 1 h. The collected samples of essential oils were dried with anhydrous Na2SO4 and stored at 4.8℃ until analyzed. The enantioselective capillary GC analysis was conducted on a Cyclosil B capillary column (30 m x 0.32 mm, film thickness 0.25 μm, 30 % hepatkis (2,3-di-O-methyl-6-O-t-butyldimethylsilyl)-β-cyclodextrin in DB-1701). The relative amounts of individual components (in %) were calculated on the basis of GC peak areas without using correction factors. Results. The composition and enantiomeric terpene distribution of essential oils from the Pinus plants cultivated in the Central Botanical Gardens of Belarus is reported. Conclusions. The obtained experimental data indicate the presence of individual enantiomer composition features of essential oils of various representatives of the pine trees that can be used in chemosystematics of the genus Pinus. A common feature for the studied species of the genus Pinus is a significant predominance of (+)-Δ3-carene over (-)-form, the levorotatory isomer of β-pinene over (+)-form. As chemomarker for the section Cembra can be used enantiomeres excess (-)-limonene.
 Keywords: Pinus, essential oil, enantiomer, chemomarker.

THE FIVE-COMPONENT SYSTEM: LITHIUM–SODIUM–POTASSIUM–SULPHATE–CHLORIDE–WATER, AT 25 °C

The system consisting of the ions Li2++, Na2++, Ka2++, Cl2++, SO4++ and water at 25 °C has been investigated by the chemical analysis of the solutions and of the wet residues. In the solid model eight volumes were found where the following solid phases were in equilibrium with solution: Li2SO4.H2O, K2SO4, Na2SO4.10H2O, K3Na(SO4)2, KLiSO4, solid solution of Na2SO4 and Li2SO4, KCl, and NaCl. Anhydrous Na2SO4 was found to exist only as a surface in the solid diagram. Another volume, LiCl.H2O, was not obtained experimentally owing to its close proximity to the LiCl corner of the diagram.Five invariant points were discovered. No ternary salt was found to exist in the interior of the phase model at the temperature of this study, 25 °C.

Fractionation of Estrogen-Methyl-Esters with Alumina Column Chromatography

A chromatographical method for fractionation of estrogen methyl ethers.100ml. of late pregnancy urine was boiled for 15 minutes with 15 vol. % of conc HCl. Hydrolyzed urine was extracted twice with 150 ml. of ether and the extract was washed twice with 25 ml. of 5% NaHCO3 solution to remove acid substances and then washed three times with water (20ml.). The ether solution was dried with anhydrous Na2SO4 and was distilled to about 10 ml. in a water bath.The contents were transferred together with 25 ml. of benzene and 25 ml. of petroleum ether into a separating funnel. The benzene petroleum ether solution was extracted twice with 25 ml. of 1.6% NaOH. Then H3BO3 (0.9 gr.) was added to the given NaOH extracts. The flask was placed in a 37°C water bath and 1 ml. of dimethylsulfate was added. The flask was stirred by a magnetic stirrer at 37°C for 30 minutes and was allowed to stand at room temperature overnight.Ten ml. of 20% NaOH and 2.5 ml. of 30% H2O2 were added to the flask and the contents of the flask were transferred to a separating funnel.The methylated estrogens were chromatographed by alumina column ; the size of the column was 0.5 * 20 cm. The column was prepared by partly filling it with petroleum ether and then adding the 2.0 gr. of Brockmann alumina (activity III). The chromatograms were run at 18°C under the pressure of 10-12 cm./Hg. The eluates was divided into 2ml. for each tube.Estrone methyl ester, estradiol methyl ester, 16-epi-estriol methyl ester and estriol methyl ester were eluated with 40% petroleum ether in benzene, benzen, 1.6% methanol in benzene and 3.0% methanol in benzene, respectively.By this method, estrogens in pregnant urine were separated into four fractions and were measured. It was then determined that the 16-epi-estriol contained in late prengnancy urine was 11.5% of the total estrogens.

魚肉中のアミンの生成について-IV

A simple, rapid and colorimetric method for the estimation of histamine, based on the extraction of histamine azo-compound with ethyl acetate, was presented. Coloration of histamine with diazo-reagent in ice bath, was stable and reproducible, and the intensity of histamine was proportional to the concentration of histamine, showing linear relation within the range from 1 to 20γ. Many well-known substances, in the amount that might be contained in fish muscle, scarcely interfered with the method. Histamine added to fish extract was recovered with satisfactory results. Applications on several species of fish muscle showed as good results as those obtained by other recent method. Analytical procedure was summarized as follows: Fish muscle extract was obtained by shaking and filtering, after being added succesively 10 volumes of water and of 5% CCl3COOH. One cc. of the extract was neutralized with 0.5% NaOH and made to 2 cc. with water and then 1 cc. of 4% Na2CO3 was added to it. To the above solution, placed in ice bath over for 3 minutes, was added 1 cc. of ice-cooled diazo-reagent and the solution was kept in ice bath. After cooling it for 3 minutes almost exactly, 7 cc. of ethyl acetate was added to it and its solution was shaken vigorously for approximately 30 seconds. After brief standing, almost all of ester layer was taken and shaken with 5 cc. of about 0.1% Na2CO3. After letting it stand, upper portion was taken and dried with granular anhydrous Na2SO4. Rose color of ester solution was immediately measured in colorimeter (filter 500mμ, cell 10mm.). Diazo-reagent was freshly prepared by adding 0.2 cc. of 5% NaNO2 to 10 cc. of ice cooled 0.1% p-nitroaniline in 0.1 N HCl solution and in advance of its use it had to be kept in ice water.

サケ・マス類のカロチノイド色素の研究-II

Three methods for estimating astaxanthin, the only carotenoid occurring in the muscle of Pacific salmons have been devised as follows: (A) The muscle (5g) was ground in a mortar and the pigment was several times extracted with acetone. The combined acetone extracts were concentrated at room temperature under nitrogen, and the pigment was extracted with petr. ether. This solution was run through a column (3.5×30cm) of cellulose powder (20g), and the column was washed with about 80-100cc of petr. ether to remove fat completely. The pigment adsorbed on the cellulose powder was then eluted with acetone. This acetone fraction was concentrated, and its volume was suitably adjusted with acetone for spectrophotometric measurement with Beckman spectrophotometer. Regarding the difference between values at 478 mμ and 600 mμ as accounting for astaxanthin, the amount of astaxanthin in fresh muscle was calculated using the value of E1%1cm (478 mμ)=2, 200 for pure astaxanthin in acetone. (B) The petr. ether solution of the pigment prepared as A, was added with small amount of anhydrous Na2SO4, and filtered through No. 4 glass filter. After removal of the solvent, the residue was dissolved in a suitable volume of petr. ether for spectrophotometric analysis. The extinction was measured at 470 mμ and 600 mμ, and the calculation was the same as A, except that E1%1cm (470 mμ)=2, 400 was used for pure astaxanthin in petr. ether. (C) The muscle was extracted with acetone as A. The volume of this solution was immediately suitably adjusted for spectrophotometric analysis. Extinction measurement and calculation were made as A. In the methods A and B, the recovery of added pure astaxanthin was 94.4-97.6% and 97.0-98.7% respectively. And there was no appreciable difference among the values obtained by the methods A, B, and C on the same material (Table 1). By these methods, astaxanthin concentration was determined on the dorsal, ventral, and caudal muscles of five species of North Pacific salmons (Table 2), on the muscle of some individuals of red salmon caught at different stations, and also on that of five species from the same station (Table 3). So it was ascertained that the muscle of red salmon is most rich in this pigment, and there was found no distinct relationship between theamount of the muscle astaxanthin and sex, body weight, body length and fattiness.

マグロ肝油の成分に就いて

Exceptlcod liver oil, little attention has been paid to the organ fat of fish. KAWAKAMI has colorimetrically determined vitamin-A content in tunny liver oil. The present paper deals with tunny liver oil, chiefly with its fatty acids and its vitamin-A content. The sample oil was prepared by extraction of the liver dehydrated by anhydrous Na2SO4 with petroleum ether (Bp. '50°C.). Owing to the readiness of oxidation in air during the chemical treatment, the samples were treated in CO2 atmosphere in so far as possible, and further the mixed fatty acids were divided into three groups:- namely first the highly unstaturated fatty acid group was separated by sodium salt acetone method, and next the lowly unsaturated group ws separated by lead salt ether method from the saturated one. Then the individual fatty acids were fractionated by distilling their methyl esters in vacuo. For futher details, the reader is referred to the attached table; the results obtained are summarised as follows: - 1) The fresh liver oil collected in spring was composed mainly of the following fatty acids; Oleic caid (30%), Clupanodonic acid (22%), Arachidonic acid (20%), Palmitic acid (19%), Stealic acid (7%), Myristic acid (5%) and a small quantity of Linolic acid. 2). By the animal experiment using albino rat, it was determined that about 9mg. of this liver oil were the lowest quantity of doses to be given daily for curing A-avitaminosis. (The vitamin-A free diet used throughout the experiment is made up to 55% of starch, 20% of fat-free fish meal, 20% of olive oil, 5% of MeCollum's salt mixture and 5 c.c. of oryzanin.)