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Showing papers on "Buffer solution published in 1969"


Journal ArticleDOI
29 Nov 1969-Nature
TL;DR: The general conclusions were that the only oxidation product of glucose in these conditions is gluconic acid, which adsorbs on the electrode in the potential range −0.2 to 0.0 V (SHE), effectively inhibiting glucose oxidation.
Abstract: Rao and Drake1 have recently reported work on the oxidation of dextrose on platinized platinum in neutral buffer solution (pH 7.4). They have shown that anodic charging curves on platinized platinum electrodes in 0.5 M dextrose solution go through an inflexion at about 0.1 V referred to standard hydrogen electrode (SHE) (where platinum starts to adsorb oxygen in neutral solution), after which oxidation is inhibited. No square root dependence was noted for the transition time to this point, indicating that the inhibitive process was not under diffusion control. In addition, the total number of coulombs required to reach the point of inflexion decreased if increasing concentrations of gluconic acid were added to the dextrose solution. They reported open circuit potential (OCP) of + 0.3 V (SHE) in deaerated gluconic acid solution (10−4 to 10−1 M), and they detected no evidence of gluconic acid oxidation in the potential range −0.6 to 0.0 V (SHE). Their general conclusions were that the only oxidation product of glucose in these conditions is gluconic acid, which adsorbs on the electrode in the potential range −0.2 to 0.0 V (SHE), effectively inhibiting glucose oxidation.

66 citations


Journal ArticleDOI
TL;DR: The isolated MA appears structurally complete, but an in vitro reconstruction of normal MA function is not obtained with the isolated, stabilized unit, and a brief MA elongation similar to anaphase movement can be induced during isolation into a solution containing magnesium and ATP.

35 citations


Journal ArticleDOI
TL;DR: Purified acid phosphatase appeared homogeneous according to the criteria of gel filtration, starch-block electrophoresis, and analytical ultracentrifugation.
Abstract: Acid phosphatase of Staphylococcus aureus PS55 was eluted from the surface of these cells with 1.0 m KCl at pH 8.5 by gentle agitation at 25 C and was purified 44-fold (51% recovery) by two cycles of dialysis and gel filtration. The eluted enzyme which had a 280/260 (nm) absorbancy ratio of 0.71 required at least 0.5 m salt solution for solubilization; however, most of the purified product which had a 280/260 (nm) absorbancy ratio of 1.72 was soluble in dilute buffer solution [0.01 m tris(hydroxymethyl)aminomethane chloride, pH 8.5]. Purified acid phosphatase appeared homogeneous according to the criteria of gel filtration, starch-block electrophoresis, and analytical ultracentrifugation. In a starch block, migration was toward the cathode at pH 8.0. Maximal activity occurred at pH 5.2 to 5.3 and salt concentration had little effect on phosphatase activity up to 1.0 m KCl or NaCl. Progressive loss of enzymatic acitivity occurred at higher salt concentrations. Molecular weight of purified acid phosphatase was estimated to be 58,000.

30 citations


Journal ArticleDOI
01 Sep 1969-Nature
TL;DR: It is shown that the continuous addition of acid or alkali to maintain a DNA solution at pH 7.0 results in the irreversible denaturation of DNA.
Abstract: THE reaction of a solution of DNA with an alkylating agent such as dimethyl sulphate results in the production of acid as the alkylating agent is hydrolysed by water. To maintain the solution at a constant pH, the liberated acid must be neutralized by the continuous addition of alkali or the reaction must be carried out in a concentrated buffer solution. Here we show that the continuous addition of acid or alkali to maintain a DNA solution at pH 7.0 results in the irreversible denaturation of DNA.

11 citations


Patent
13 Mar 1969
TL;DR: An electrophoretic separation apparatus for the support-free continuous separation of molecular fractions in a buffer solution has a thin flat electrophoresis chamber defined between watercooled plates through which the mixture of fractions and buffer solution is passed and wherein the solution is subjected to a unidirectional field transverse to the direction of mass flow to separate the fractions as mentioned in this paper.
Abstract: An electrophoretic separation apparatus for the support-free continuous separation of molecular fractions in a buffer solution has a thin flat electrophoresis chamber defined between watercooled plates through which the mixture of fractions and buffer solution is passed and wherein the solution is subjected to a unidirectional field transverse to the direction of mass flow to separate the fractions. Subsequently the separated fractions are sedimented out of their respective portions of buffer solution in collecting vessels ahead of the outlets for the solution. Downstream of the collecting vessels is mechanical or hydrostatic pump or flow-control means which makes the fluid flow through the apparatus.

9 citations


Patent
09 Jan 1969
TL;DR: The alpha acids and beta acids are extracted from resinous hop material such as lupulin in the following process steps: (1) (optional) the hop material is given an initial wash with sodium or potassium hydrogen phosphate buffer solution of pH 4-9 to extract selectively tannins and fatty acids, the temperature being kept low enough to avoid substantial dissolution of the alpha acid content of the hop fraction as discussed by the authors.
Abstract: 1,236,731. Hop extracts. WATNEY COMBE REID & CO. Ltd. 7 Jan., 1970 [9 Jan., 1969], No. 1393/69. Heading C2C. [Also in Division C6] The alpha acids and beta acids are extracted from resinous hop material such as lupulin in the following process steps: (1) (optional) the hop material is given an initial wash with sodium or potassium hydrogen phosphate buffer solution of pH 4-9to extract selectively tannins and fatty acids, the temperature being kept low enough to avoid substantial dissolution of the alpha acid content of the hop fraction; (2) the alpha acids are then extracted with the aid of aqueous disodium or dipotassium hydrogen phosphate, or sodium or potassium citrate, at a pH in the range 7 to 9 and a temperature between 40‹ and 90‹ C.; and (3) the beta acids are extracted from the residue with a 0A2-2A0% by weight aqueous solution of sodium or potassium carbonate at a temperature in the range 25‹ to 100‹ C. Crystallization of the extracted alpha acids and beta acids may be promoted by the addition of acid, e.g. citric acid and gaseous carbon dioxide, respectively. The extractions may be performed by percolating alkali through a column of the lupulin-rich powder or by spraying the alkali on to the inside surface of a packed bed of the powder in a basket centrifuge. In both cases a filter aid (specified) should be included. The extracted alpha acids may be isomerized by boiling at atmospheric pressure for 2 hours at a pH of 9 (or longer at a lower pH). The extracted beta-acids may be oxidized to hulupones by gaseous oxygen at a temperature in the range 70-90‹ C.

8 citations


Patent
24 Sep 1969
TL;DR: In this article, an observer for measuring the partial pressure of CO2 in a stream of invariant liquid is presented, where a BICARBONATE BUFFER solution is used.
Abstract: A MONITOR FOR CONTINUOUSLY MEASURING THE PARTIAL PRESSURE OF CO2 IN A STREAM OF INTRAVENOUS LIQUID INCLUDES AN ION SENSITIVE ELECTRODE HAVING A BICARBONATE BUFFER SOLUTION. THE ELECTRODE IS POSITIONED IN A SAMPLING CAVITY WHICH IS MAINTAINED CONTINUOUSLY FULL OF THE INTRAVENOUS LIQUID WHICH IS TO BE MONITORED AND THE BUFFER SOLUTION IS SEPAREATED FROM THE CAVITY BY A SEMIPERMEABLE TEFLON MEMBRANE. A SAMPLING STREAM OF THE LIQUID IS DIRECTED INTO THE BODY OF LIQUID IN THE CAVITY AND AGAINST THE MEMBRANE AND AT LEAST A PORTION OF THE CO2 IN THE STREAM PASSES THROUGH THE MEMBRANE TO VARY THE PH OF THE BUFFER SOLUTION AS A FUNCTION OF THE PARTIAL PRESSURE OF THE CO2 IN THE SAMPLE STREAM. THE CHANGE IN PH IS MEASURE TO PROVIDE AN INDICATION OF THE PARTIAL PRESSURE IN THE SAMPLE. CALIBRATION OF THE MONITOR IS EFFECTED BY DRAINING THE CHAMBER AND EXPOSING THE MEMBRANE TO A NEBULIZED GASEOUS MIXTURE OF THE LIQUID AND A STANDARD CO2 OF A KNOWN PARTIAL PRESSURE.

7 citations


Patent
05 Sep 1969
TL;DR: In this article, the authors describe a process for uncovering infrinsic factors by a BATCH CHROMATOGRAPHY (BCG) process, in which an Ion exchange resin is used.
Abstract: A PROCESS FOR PURIFYING INTRINSIC FACTOR BY A BATCH CHROMATOGRAPHY PROCESS WHICH UTILIZES AN ION EXCHANGE RESIN; AND THE RESULTANT HIGH PURITY INTRINSIC FACTOR. TYPICALLY, IMPURE INTRINSIC FACTOR IS DISSOLVED IN A BUFFER SOLUTION HAVING RELATIVELY LOW PH AND IONIC STRENGTH, AND THE RESULTANT SOLUTION IS CONTACTED WITH A CELLULOSIC EXCHANGE RESIN. THE RESIN IS SEPARATED FROM THE SOLUTION AND THE PURIFIED INTRINSIC FACTOR IS ELUTED THEREFROM WITH A BUFFER SOLUTION HAVING A HIGHER PH AND IONIC STRENGTH THAN THE BUFFER SOLUTION IN WHICH THE IMPURE INTRINSIC FACTOR WAS DISSOLVED. THE PRODUCT IS RECOVERED FROM THE ELUATE BY EVAPORATING THE LIQUID SOLVENT. THE RESIDUE, WHICH IS THE PURIFIED PRODUCT, HAS A POTENCY OF AT LEAST 1 N.F. UNIT IN AMOUNTS AS LOW AS 0.5 MG.

6 citations


Patent
21 Apr 1969
TL;DR: A therapeutic enzyme such as L-Asparaginase is purified from a protein mixture containing the enzyme by adding a controlled amount of a buffer solution which will solubilize a major portion of the protein mixture, but only a minor portion of it, for example, a sodium acetate buffer solution having a pH in the range of 5.3 to 5.7 as discussed by the authors.
Abstract: A therapeutic enzyme such as L-Asparaginase is purified from a protein mixture containing the L-Asparaginase by adding a controlled amount of a buffer solution which will solubilize a major portion of the protein mixture, but only a minor portion of the L-Asparaginase, for example, a sodium acetate buffer solution having a pH in the range of 5.3 to 5.7, and thoroughly mixing the resulting dispersion until the protein is solubilized and a solution is formed containing the enzyme dispersed therein. The enzyme is then separated from the buffer solution by suitable means such as centrifugation. Noxious agents such as endotoxin and pyrogen are removed from the purified or partially purified L-Asparaginase by intimate contact with a water insoluble nonionic sorbent material. Additionally, protectant agents such as Vitamin C can be added to the purified or partially purified L-Asparaginase and thereby cause an increase in the storage life thereof.

3 citations


Patent
25 Jun 1969
TL;DR: In this paper, the authors present a composition for the determination of amino acid arylamidase (leucinaminopeptidase) consisting of (a) alanine hydrazide, (b) a buffer solution with a pH of 6.5 to 7.5, with or without (c) an aromatic aldehyde colour reagent, for example p-dimethylamino-benzaldehyde.
Abstract: 1,176,968. Determining amino acid arylamidase. ARZNEIMITTELWERK DRESDEN VEB. 8 Sept., 1967, No. 41197/67. Heading B1X. A composition for the determination of amino acid arylamidase (leucinaminopeptidase) comprises (a) alanine hydrazide, alanine pnitroanilide or alanine-#-naphthylamide, (b) a buffer solution with a pH of 6.5 to 7.5, with or without (c) an aromatic aldehyde colour reagent, for example p-dimethylamino-benzaldehyde. In use, the sample, for example blood serum, is incubated with the substrate and the buffer solution. When alanine p-nitroanilide is used, the p-nitro-aniline formed is determined colorimetrically, optionally in a kinetic test. When alanine hydrazide or alanine-#-naphthylamide is used, the hydrazine or #-naphthylamine formed react with the aromatic aldehyde colour reagent and the solution is acidified to give a coloured salt, the extinction of which is measured. A test pack contains solutions of the alanine derivative and of the buffer, optionally mixed together, with or without a solution of the colour reagent.

2 citations


Journal ArticleDOI
01 Jan 1969
TL;DR: In this paper, the electrophoretic method was used to separate and identify eight preservatives (salicylic acid, benzoic acid, sorbic acid and deodorant), a sterilizer (nitrofurazone), and three artificial sweetners (saccharin sodium, sodium cyclamate and dulcin) by using 1% borax solution, Kolthoff buffer solution (pH 4.0 and 5.8) or Atkins-Pantin buffer solution(pH 10) as the electrolyte.
Abstract: The paper electrophoretic method to separate and identify eight preservatives (salicylic acid, benzoic acid, sorbic acid, dehydroacetic acid, ethyl p-hydroxybenzoate, resorcinol, β-naphthol and p-chlorobenzoic acid), a sterilizer (nitrofurazone), and three artificial sweetners (saccharin sodium, sodium cyclamate and dulcin) was investigated by using 1% borax solution, Kolthoff buffer solution (pH 4.0 and 5.8) or Atkins-Pantin buffer solution (pH 10) as the electrolyte. The mobilities of the compounds were shown as the relative one to flavianic acid, and tabulated. All the compounds could be identified by selecting the electrolytes.