Trichloroacetic Acid Solution Research Articles

Extraction of Pentosans from Wheat Flour with Trichloroacetic Acid Solutions

AbstractPentosans were extracted from wheat flour with 15% trichloroacetic acid (TCA) at 2°C. The TCA was extracted with ether and the aqueous solution dialyzed, centrifuged and lyophilized. Subfractions obtained by fractionation on Sepharose 6B and by ammonium sulfate precipitation were analyzed for carbohydrates, protein and hydroxyproline. The pentosans contained a high molecular weight component having only arabinose and galactose as monosaccharides, and 4.4% protein, of which 3% w/w was hydroxyproline.

Cytology of the pituitary gland of the Plains viscacha (Lagostomus maximu)

The anatomy of the pituitary gland of the Plains viscacha (Lagostomus maximus) is described. The pituitary gland in various physiological states has been investigated in order to localise the secretory sites of the trophic hormones. The various cell types of the pituitary gland were distinguished on the basis of their morphological characteristics, tinctorial properties and differential solubilities of the protein hormones in trichloroacetic acid solutions. Two cell types were found in the pars tuberalis, three cell types in the pars intermedia and six chromophi1 cell types in the pars anterior. Their possible functions are discussed.

Electrophoretic separation of γ-glutamyl transpeptidase isoenzymes on cellulose acetate “Cellogel”

A method was described for separation of γ-glutamyl transpeptidase (γ-GTP) isoenzymes by cellulose acetate membrane (Cellogel). Enzyme activity staining was carried out by use of γ-L-glutamyl-α-naphthylamide as substrate and fast blue B as color developing agent. Zymogram on Cellogel membrane was treated with 5% trichloroacetic acid solution and applied for densitometry.The conditions for this method (concentration of substrate, diazo reagent, glycylglycine, pH of buffer, incubation time, etc.) were examined and optimal conditions were proposed.This method was simple and sensitive enough to detect γ-GTP isoenzyme patterns from the normal serum containing 30mU/ml activity. Linear relationship between color development of zymogram and enzyme activity was also obtained from 30mU/ml to 230mU/ml in serum sample and this method, therefore, was available for the routine work as semi-quantitative method.

Protein-binding assay for cyclic AMP: Possible interference by traces of trichloroacetate

When cyclic AMP is to be extracted from animal and plant tissues a 5% trichloroacetic acid (TCA) solution is often used as the initial extraction medium. We have shown that traces of trichloroacetate remain in the extract even after multiple solvent extraction and this impurity can cause inflated estimates of cyclic AMP (cAMP) in the protein-binding assay. This will only occur when it is necessary to employ relatively large volumes of TCA (i.e., tissues containing low levels of cAMP). For such tissues we recommend the use of a thin layer chromatographic purification stage to separate cAMP from the trichloroacetate residue.

Factor Analysis as a Complement to Band Resolution Techniques. III. Self Association in Trichloroacetic Acid

Digitized infrared spectra of nine solutions of trichloroacetic acid in CCl4 have been studied in the carbonyl stretching region. At all concentrations only two bands are visually apparent. However, factor analysis indicates the presence of four absorbing components. The contour resolution technique gives a monomer band at 1786 cm−1, a dimer band at 1749 cm−1, and a third band close to the dimer frequency at approximately 1735 cm−1. Examination of the changes in Cauchy–Gauss shape ratio of the monomer band with increasing concentration indicates the presence of an unresolved component. The band at 1735 cm−1 and the unresolved band near the monomer peak at 1786 cm−1 are assigned to absorption of carbonyl groups in linear polymers of trichloroaceticacid. The monomer–dimer equilibrium constant was calculated from the molar absorption coefficients and absorbances of monomer and dimer bands. The average value over the concentration range 0.305 × 10−3 to 0.1603 M was 287 l/mol at 33.9 ± 0.5 °C.

Direct detection of protein kinases on electropherograms

Since their discovery protein kinases have been usually tested by taking advantage of the solubility of ATP in deproteinizing agents like 10% trichloroacetic acid, in which protein bound phosphorylserine and phosphorylthreonine are quite stable. By such procedures at the end of incubation the excess of [32P] ATP is easily removed from the 32 P-labelled protein either by centrifugation followed by several washings [l-3] or by applying the sample on chromatographic paper [4] or on filters [5] which are subsequently eluted by trichloroacetic acid solutions. The counting of the protein residue at the end of both these procedures gives a reasonably precise measure of the amount of 32P transferred by the protein kinase from [32P] ATP to the phosphoprotein. In the last few years more and more attention has been devoted to protein kinases which have been found to differentiate both for their substrate specificity and for their sensitivity to cyclic nucleotides (see [6] ). As expected, investigators make extensive use of analytical gel electrophoresis to characterize protein kinases, though the only known procedure to localize the enzyme activity is to cut the gel into slices and to test the protein kinase eluted from every single segment by one of the methods previously mentioned [.5,7,8]. In the present note we shall describe a much less complicated and more rapid procedure which proved quite satisfactory for a direct evaluation of protein kinase activities on both polyacrylamide and acetylcellulose electropherograms. In principle such a method consists in laying down the gel, after electrophoresis, on a strip of chromatographic paper imbibed with a sample containing a buffer system, [“‘PI ATP with

A colorimetric method for the determination of deoxyribonucleic acid in adipose tissue

A method is described for measuring the deoxyribonucleic acid (DNA) content of small samples of adipose tissue or free fat cells. Lipids and acid-soluble nucleotides are first removed by extraction with a cold diethyl ether-ethanol mixture containing 10 per cent. m/V of trichloroacetic acid. DNA is then measured by hydrolysing the nucleoprotein residue in a 5 per cent. solution of trichloroacetic acid at 90 °C for 20 min, followed by treatment with p-nitro-phenylhydrazine and measurement of the hydrazone at 560 nm.

Studies on Analysis of Pharmaceutical Preparations. XXIX. Colorimetric Determination of Acetaminophen in Anti-cold Pharmaceutical Preparations

Spectrophotometric Determination of acetaminophen in pharmaceutical preparations is described. Acetaminophen was hydrolysed by refluxing with perchloric acid to produce p-aminophenol which was reacted with p-dimethyl aminocinnamaldehyde in dilute trichloracetic acid solution to give a red color, which showed absorption maximum at 520 nm. Interference by the presence of phenacetin and sulpyrine can be eliminated by their extraction with chloroform in basic medium or extraction with ethyl acetate in acidic medium.

Influence of azoles as corrosion inhibitor towards 3003 aluminum in trichloroacetic acid solution

Abstract2‐Mercaptobenzthiozole, 1,2,3‐benztriazole, 2‐methylbenzthiazole and indole are efficient inhibitors of the corrosion of aluminium 3003 in 0.1 N trichloroacetic acid. With the exception of 1,2,3‐benztriazole which is a mixed type inhibitor the other compounds are cathodic inhibitors. The introduction of ‐SH‐group is favourable. The effect of the inhibitors may be due to the fact that the particular substance is adsorbed to the metal surface where stable bonds are formed between metal and sulfur and nitrogen respectively. The metal‐sulfur bond is stronger.

2-mercaptothiazoline as corrosion inhibitor for copper in acidic media

The influence of 2-mercaptothiazoline as a corrosion inhibitor for copper in acetic acid, monochloroacetic acid, dichloroacetic acid and trichloroacetic acid solutions has been investigated. The inhibitive power of 2-mercaptothiazoline among above stated acids is in the following order: trichloroacetic acid > dichloroacetic acid > monochloroacetic acid > acetic acid. The inhibition afforded by 2-mercaptothiazoline may be attributed to its chelate-forming tendency towards copper ions. The percentage efficiency obtained by weight loss method is correlated with the Tafel slope. The reaction is cathodically controlled.

On the Determination of Phosphates in Foods

To establish the determination methods of phosphates in foods, the following methods were examined, being followed with satisfactory results. Polyphosphates contained in foods could be separated qualitatively by thin-layer chromatography using Avicel-SF cellulose powder as adsorbent and a mixture of 0.5% pyridine-acetone solution and 20% trichloroacetic acid solution as the developing solvent. The quantity of phosphates was determined indirectly by determining the amount of molybdenum by atomic absorption spectrophotometry, after the formation of complex between phosphate and molybdate. Ion-exchange column chromatographic technique was applied for the separation of various kinds of polyphosphates contained in soft drink. These methods were applied to various kinds of foods, and from our results it was found that polyphosphates were present only in pressed ham, sausage and soft drink, and the amount of phosphates added to foods was found to be not so much.

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%.

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%.

Spectrographic Determination of Lead in Blood

A method is described for the determination of lead in blood covering the range 5 to 100 µg of lead per 100 g of blood (0.05 to 1 ppm). Lead is extracted from uncoagulated whole blood using a trichloroacetic acid (TCA) solution. A portion of the supernatant liquid is spectrographically analyzed using a dc arc technique.

Coulometric Actinometry Using Trichloroacetic Acid

Abstract Coulometric determination of chloride which is photolytically generated from trichloroacetic acid (TCA) is used for actinometry. Silver (I) is coulometrically generated from a silver anode and the change in chloride ion concentration is monitored potentiometrically. Photolysis - coulometry coupling yields a linear relationship between time of photolysis of solutions of TCA and the microequivalents of electrons required for titration back to the initial solution potential. If the recommended procedure is followed, errors about ten times those found for titration of standard chloride solutions are obtained.

ウニの冷凍に関する研究-II

On account of the necessity to extract or separate carbonyl compounds from sea urchin gonads and fish eggs without changing their properties, the gas liquid chromatographic figures of carbonyls in these eggs, obtained by the ordinary steam-distilling method, was examined. In this examination the N2 gas bubbling method, a method of clear trichloro-acetic acid solution after removal of the protein and the newly devised 80% ethyl-alcohol extracting method, were compared. In addition to the above a simultaneous determination method of total carbonyl and oxoacid in fish eggs was investigated. The results are as follows; 1) A fairly large amount of acetaldehyde, and a small amount of acetone and crotonaldehyde, were produced. On the other hand iso-valeraldehyde or 3-methyl butylaldehyde decreased during steam-distillation. 2) Acetaldehyde was also produced by heating under N2 aeration, but iso-valeraldehyde or 3-methyl butylaldehyde did not decrease. 3) A small amount of threonine, together with glucose, decomposed to acetaldehyde during steam-distillation. 4) Recoveries of total carbonyl and oxo-acid contents in fish eggs determined by the newly devised method, were 92% on the average. The total carbonyl and oxo-acid content of sea urchin gonads frozen at -10±3°C for three months, was about three times as much as the value of walleye pollock eggs and rainbow trout eggs stored under same conditions.

Direct Determination of the Thiobarbituric Acid Value in Trichloracetic Acid Extracts of Fish as a Measure of Oxidative Rancidity

AbstractThe possibilities of the direct determination of the thiobarbituric acid (TBA) value in trichloracetic acid (TCA) extracts instead of distillates were evaluated. Tests carried out on herring (Clupea harengus L.), redfish (Sebastes marinus L.), cod (Gadus morhua L.), plaice (Pleuronectes platessa L.) and spurdog (Squalus acanthias L.) of varying degree of oxidation gave 95.3% recovery in the teleost species but only 75.2% in the elasmobranch spurdog, due to the urea present. With the distillation technique, recoveries were lower and averaged 66.1% for teleosts and 43.0% for spurdog. Addition of 0.1% of both propyl gallate and EDTA to the TCA solution lowered TBA values by 25 to 59%. When fish samples were submitted to a 4 hours′ forced oxidation period, TBA values increased to a greater extent with the direct extraction procedure than with the distillation method.

Homogeneous precipitation of beryllium by means of trichloroacetic acid hydrolysis and determination as phosphate

A solution of trichloroacetic acid, on heating, undergoes gradual decomposition to chloroform and carbon dioxide, accompanied by a rise in pH. This principle has been applied for the homogeneous precipitation of beryllium in presence of phosphate ions. The effect of alkali ions (Na and K) on the composition of the precipitate has been investigated. The method has been successfully applied for the determination of beryllium in beryls.

Nucleic acid metabolism in the ruminant. Determination of nucleic acids in digesta.

1. Procedures, based on those of Schmidt & Thannhauser (1945) and Schneider (1945), for the extraction and estimation of nucleic acids in bovine digesta were examined in detail.2. Final methods which were suitable for routine determination of RNA and DNA were essentially as follows. Digesta samples were extracted in the cold, first with a solution of trichloroacetic acid in ethanol, then with aqueous trichloroacetic acid solution and finally with lipid solvents. The dried residue was hydrolysed with alkali, purified by passage through a Dowex resin, and the RNA, in the form of mononucleotides, determined by U.V. absorption. DNA was determined separately in hot perchloric acid extracts of the original dried residue by colorimetric estimation of the deoxyribose content.

A Sensitive Visible Spectrophotometric Method for Copper Using Bis-Substituted Thiocarbamoyl Trisulfides

Abstract Bis-substituted thiocarbamoyl disulfides (thiuram disulfides) were investigated as chromogenic reagents for the analysis of copper in trichloroacetic acid solutions. It was found that hydrogen peroxide speeded color development, increased color stability and enhanced color intensity in a trichloroacetic acid-alcohol matrix. In the presence of hydrogen peroxide, all copper complexes had molar absorptivities exceeding 30,000. Bis-pentamethylene thiocarbamoyl disulfide was selected as the best commerically available reagent of those investigated. The procedure is almost interference free, silver and mercury being the most serious interference. The sensitivity is 6 × 10−3 micrograms/cm2.