scholarly journals THE PENETRATION OF BASIC DYE INTO NITELLA AND VALONIA IN THE PRESENCE OF CERTAIN ACIDS, BUFFER MIXTURES, AND SALTS

1926 ◽  
Vol 10 (2) ◽  
pp. 271-287 ◽  
Author(s):  
Marian Irwin
Keyword(s):  
Acetic Acid ◽  
Ph Value ◽  
Tap Water ◽  
Base Cations ◽  
Living Cells ◽  
Acetate Buffer ◽  
Acetate Buffer Solution ◽  
Neutral Salt ◽  
Buffer Solution ◽  
Rate Of Penetration

When living cells of Nitella are exposed to an acetate buffer solution until the pH value of the sap is decreased and subsequently placed in a solution of brilliant cresyl blue, the rate of penetration of dye into the vacuole is found to decrease in the majority of cases, and increase in other cases, as compared with the control cells which are transferred to the dye solution directly from tap water. This decrease in the rate is not due to the lowering of the pH value of the solution just outside the cell wall, as a result of diffusion of acetic acid from the cell when cells are removed from the buffer solution and placed in the dye solution, because the relative amount of decrease (as compared with the control) is the same whether the external solution is stirred or not. Such a decrease in the rate may be brought about without a change in the pH value of the sap if the cells are placed in the dye solution after exposure to a phosphate buffer solution in which the pH value of the sap remains normal. The rate of penetration of dye is then found to decrease. The extent of this decrease is the greater the lower the pH value of the solution. It is found that hydrochloric acid and boric acid have no effect while phosphoric acid has an inhibiting effect at pH 4.8 on stirring. Experiments with neutral salt solutions indicate that a direct effect on the cell (decreasing penetration) is due to monovalent base cations, while there is no such effect directly on the dye. It is assumed that the effect of the phosphate and acetate buffer solutions on the cell, decreasing the rate of penetration, is due (1) to the penetration of these acids into the protoplasm as undissociated molecules, which dissociate upon entrance and lower the pH value of the protoplasm or to their action on the surface of the protoplasm, (2) to the effect of base cations on the protoplasm (either at the surface or in the interior), and (3) possibly to the effect of certain anions. In this case the action of the buffer solution is not due to its hydrogen ions. In the case of living cells of Valonia under the same experimental conditions as Nitella it is found that the rate of penetration of dye decreases when the pH value of the sap increases in presence of NH3, and also when the pH value of the sap is decreased in the presence of acetic acid. Such a decrease may be brought about even when the cells are previously exposed to sea water containing HCl, in which the pH value of the sap remains normal.

Separation of trivalent actinides from lanthanides in an acetate buffer solution using Cyanex 301

2006 ◽  
Vol 94 (5) ◽  
Author(s):  
Jack D. Law ◽  
Dean R. Peterman ◽  
Terry A. Todd ◽  
Richard D. Tillotson
Keyword(s):  
Acetic Acid ◽  
Ammonium Acetate ◽  
Separation Process ◽  
Acetate Buffer ◽  
Acetate Buffer Solution ◽  
Buffer Solution ◽  
Strip Solution ◽  
Trivalent Actinides ◽  
Separation Factors ◽  
Cyanex 301

SummaryThe separation of trivalent actinides from the lanthanides using the active extractant in the Cyanex 301 reagent, bis(2,4,4-trimethylpentyl)dithiophosphinic acid, was studied. Specifically, the extractant was studied with an ammonium acetate/acetic acid buffered feed that would result from a transuranic separation process utilizing an ammonium acetate strip solution. Separation factors of

scholarly journals THE EFFECT OF ACETATE BUFFER MIXTURES, ACETIC ACID, AND SODIUM ACETATE, ON THE PROTOPLASM, AS INFLUENCING THE RATE OF PENETRATION OF CRESYL BLUE INTO THE VACUOLE OF NITELLA

1927 ◽  
Vol 11 (2) ◽  
pp. 111-121 ◽  
Author(s):  
Marian Irwin
Keyword(s):  
Acetic Acid ◽  
Phosphate Buffer ◽  
Sodium Acetate ◽  
Ph Value ◽  
Specific Effect ◽  
Acetate Buffer ◽  
Rate Of Penetration ◽  
Cresyl Blue ◽  
Inhibiting Effect ◽  
Buffer Mixture

When living cells of Nitella are exposed to a solution of sodium acetate and are then placed in a solution of brilliant cresyl blue made up with a borate buffer mixture at pH 7.85, a decrease in the rate of penetration of dye is found, without any change in the pH value of the sap. It is assumed that this inhibiting effect is caused by the action of sodium on the protoplasm. This effect is not manifest if the dye solution is made up with phosphate buffer mixture at pH 7.85. It is assumed that this is due to the presence of a greater concentration of base cations in the phosphate buffer mixture. In the case of cells previously exposed to solutions of acetic acid the rate of penetration of dye decreases with the lowering of the pH value of the sap. This inhibiting effect is assumed to be due chiefly to the action of acetic acid on the protoplasm, provided the pH value of the external acetic acid is not so low as to involve an inhibiting effect on the protoplasm by hydrogen ions as well. It is assumed that the acetic acid either has a specific effect on the protoplasm or enters as undissociated molecules and by subsequent dissociation lowers the pH value of the protoplasm. With acetate buffer mixture the inhibiting effect is due to the action of sodium and acetic acid on the protoplasm. The inhibiting effect of acetic acid and acetate buffer mixture is manifested whether the dye solution is made up with borate or phosphate buffer mixture at pH 7.85. It is assumed that acetic acid in the vacuole serves as a reservoir so that during the experiment the inhibiting effect still persists.

Enzymatic hydrolysis of chitosan in acetate buffer solution

2015 ◽  
Vol 88 (4) ◽  
pp. 647-651 ◽  
Author(s):  
V. V. Chernova ◽  
A. S. Shurshina ◽  
M. V. Bazunova ◽  
E. I. Kulish
Keyword(s):  
Enzymatic Hydrolysis ◽  
Acetate Buffer ◽  
Acetate Buffer Solution ◽  
Buffer Solution ◽  
Hydrolysis Of

Collaborative Study of an Ultraviolet Method for Measuring Diquat Content in Formulations

1968 ◽  
Vol 51 (6) ◽  
pp. 1304-1305
Author(s):  
A A Carlstrom
Keyword(s):  
Systematic Error ◽  
Random Error ◽  
Coefficient Of Variation ◽  
Collaborative Study ◽  
Acetate Buffer ◽  
Acetate Buffer Solution ◽  
Buffer Solution ◽  
Standard Curve ◽  
Two Samples

Abstract The ultraviolet method for diquat described by Yuen, Bagness, and Myles in 1967 was collaboratively studied with formulations containing 2 lb diquat/gal. A portion of the sample is diluted with an acetate buffer solution and the absorbance is measured at 310 mμ the diquat content is obtained by reference to a standard curve prepared from known diquat concentrations. Single determinations on two samples by thirteen collaborators show an overall coefficient of variation of 2.4%. The coefficient of variation for random error is 1.0%, and for systematic error 1.6%. The method is recommended for adoption as official, first action.

Preparation and characterization of a poly-o-phenylenediamine film modified glassy carbon electrode as a H2O2 sensor

2013 ◽  
Vol 91 (11) ◽  
pp. 1077-1084 ◽  
Author(s):  
Wenying Zhai ◽  
Xiuying Tian ◽  
Yun Yan ◽  
Yuehua Xu ◽  
Yuechun Zhao ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Electrochemical Impedance ◽  
Monomer Concentration ◽  
Acetate Buffer ◽  
Acetate Buffer Solution ◽  
Carbon Electrode ◽  
Modified Glassy Carbon Electrode ◽  
Buffer Solution

A poly-o-phenylenediamine film modified glassy carbon electrode (PoPD/GC) was successfully prepared by cyclic voltammetry in acetate buffer solution. The polymerization mechanism of oPD is discussed. The impedance behavior and morphology of the PoPD membrane were characterized using cyclic voltammetry, electrochemical impedance spectroscopy, and scanning electron microscopy, respectively. It is discovered that the PoPD/GC prepared only in acetate buffer solution had dual electrocatalytic activity toward the oxidation and reduction of H2O2. The optimal buffer solution pH, scanning rate, monomer concentration, and number of scannings for film forming were 4.2, 0.05 V s−1, 6.0 mmol L−1, and 30, respectively. The linear ranges between the anodic (Δia) or cathodic (Δic) current and H2O2 concentration were 0.07−1.0 × 104 and 0.04−4.5 × 104 μmol L−1, respectively. The corresponding calibration curves were Δia (μA) = 8.03c (mmol L−1) + 6.36 (n = 18, R2 = 0.9989) and Δic (μA) = −5.52c (mmol L−1) − 0.77 (n = 18, R2 = 0.9990) with a detection limit of 0.03 and 0.02 μmol L−1 (S/N = 3), respectively. The PoPD/GC prepared in the optimal conditions showed good stability and quick response (<0.2 s) to H2O2, which was successfully applied to the determination of H2O2 in real water samples with satisfactory results.

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