pH-Metric log P. 3. Glass electrode calibration in methanol-water, applied to pKa determination of water-insoluble substances

1993 ◽  
Vol 65 (1) ◽  
pp. 42-49 ◽  
Author(s):  
Alex. Avdeef ◽  
John E. A. Comer ◽  
Simon J. Thomson
Keyword(s):  
Glass Electrode ◽  
Log P ◽  
Pka Determination

PHYSICOCHEMICAL PROPERTIES DETERMINATION OF PICROSIDE-II

INDIAN DRUGS ◽  
2019 ◽  
Vol 56 (08) ◽  
pp. 27-37
Author(s):  
S. Bhusari ◽  
A Chaudhary ◽  
G Shrangare ◽  
M. Rindhe ◽  
P. Wakte ◽  
...  
Keyword(s):  
Physicochemical Properties ◽  
Linseed Oil ◽  
Angle Of Repose ◽  
Log P ◽  
P Value ◽  
Solubility Study ◽  
Picroside Ii ◽  
Compressibility Index ◽  
Pka Determination

The aim of the present study is to determine the physicochemical properties of Picroside-II, a phytochemical obtained from the herb of Picrorhiza kurroa. The solubility study of picroside-II shows that it has better solubility in water up to 2.46 mg/mL than organic solvents. The solubility of picroside-II in linseed oil was found to be 71.46 mg/mL. The solubility of Picroside-II in surfactant like Transcutol P and labrasol was found to be 907.80 and 535.90 mg/mL, respectively. Picroside-II had a melting point in the range of 130 to 135°C. The log P value of picroside-II was estimated using shake flask method followed by UV analysis. The log P value of picroside-II was found to be -0.09675, which shows its hydrophilicity. The pKa determination of picroside-II was carried out by using UV-visible spectrophotometer and the pKa value was found to be 7.80. The particle size distribution of picroside-II powder was also carried out and the maximum particles of picroside-II are in the range of 53-75 μm. Flow properties of picroside-II were also studied. bulk and tapped density of picroside-II powder was found to be 0.149 and 0.248, respectively. The Hausner ratio and compressibility index were also calculated and it was found to be 1.66 and 39.99, which confirm the poor flow properities of picroside-II powder. The angle of repose of picroside-II was found to be 41.08°, which shows the passable flow of picroside-II. Water was found to be the better extractive solvent for picroside-II; the extractive value of picroside-II in water was found to be 9.12%.

scholarly journals The Determination of Gastric Acidity by the Glass Electrode

1965 ◽  
Vol 49 (2) ◽  
pp. 178-188 ◽  
Author(s):  
Edward W. Moore ◽  
Robert W. Scarlata
Keyword(s):  
Gastric Acidity ◽  
Glass Electrode

scholarly journals pKa Determination of a Histidine Residue in a Short Peptide Using Raman Spectroscopy

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 405 ◽  
Author(s):  
Brett H. Pogostin ◽  
Anders Malmendal ◽  
Casey H. Londergan ◽  
Karin S. Åkerfeldt
Keyword(s):  
Raman Spectroscopy ◽  
Nmr Spectroscopy ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Peptide Sequence ◽  
Short Peptide ◽  
Dependent Behavior ◽  
Pka Determination ◽  
Key Functional Groups

Determining the pKa of key functional groups is critical to understanding the pH-dependent behavior of biological proteins and peptide-based biomaterials. Traditionally, 1H NMR spectroscopy has been used to determine the pKa of amino acids; however, for larger molecules and aggregating systems, this method can be practically impossible. Previous studies concluded that the C-D stretches in Raman are a useful alternative for determining the pKa of histidine residues. In this study, we report on the Raman application of the C2-D probe on histidine’s imidazole side chain to determining the pKa of histidine in a short peptide sequence. The pKa of the tripeptide was found via difference Raman spectroscopy to be 6.82, and this value was independently confirmed via 1H NMR spectroscopy on the same peptide. The C2-D probe was also compared to other Raman reporters of the protonation state of histidine and was determined to be more sensitive and reliable than other protonation-dependent signals. The C2-D Raman probe expands the tool box available to chemists interested in directly interrogating the pKa’s of histidine-containing peptide and protein systems.

Physicochemical Properties of a New Multicomponent Cosolvent System for the pKa Determination of Poorly Soluble Pharmaceutical Compounds

2007 ◽  
Vol 90 (8) ◽  
pp. 1538-1553 ◽  
Author(s):  
Karl J. Box ◽  
Gergely Völgyi ◽  
Rebeca Ruiz ◽  
John E. Comer ◽  
Krisztina Takács-Novák ◽  
...  
Keyword(s):  
Physicochemical Properties ◽  
Pharmaceutical Compounds ◽  
Poorly Soluble ◽  
Pka Determination

NaCl and CaCl2 activity coefficients in mixed aqueous solutions

1965 ◽  
Vol 20 (6) ◽  
pp. 1332-1336 ◽  
Author(s):  
Edward W. Moore ◽  
James W. Ross
Keyword(s):  
Ionic Strength ◽  
Activity Coefficients ◽  
Technical Assistance ◽  
Osmotic Coefficients ◽  
Electrode System ◽  
Glass Electrode ◽  
Concentration Data ◽  
Harned's Rule ◽  
Potentiometric Measurement

In the investigation of numerous physiological phenomena it is the activity of an ion species which is desired, rather than stoichiometric concentration. The calculation of mean ionic activity from known concentration data requires accurate activity coefficients (ggr). This report concerns the determination of ggrNaCl and ggrCaCl2 in mixed NaCl-CaCl2 solutions by potentiometric measurement with a sodium-selective glass electrode-Ag/AgCl electrode system over the ionic strength range 0.05–0.5 m. Log ggrNaCl varied linearly, at constant total ionic strength, with the ionic strength of CaCl2 in the mixture, in accordance with Harned's rule. From data thus obtained, ggrCaCl2 coefficients in such mixed solutions have been calculated and compared with values calculated from published osmotic data. Resulting activity coefficient curves for ggrCaCl2 are presented over the concentration range encountered in serum and other extracellular fluids. Note: (With the Technical Assistance of Leonard Kaye and Leonard L. Anderson) glass electrodes; ion interaction; electrolyte metabolism; Harned's rule; membrane transport; osmotic coefficients Submitted on March 11, 1965

scholarly journals THE DETERMINATION OF SODIUM IN BODY FLUIDS BY THE GLASS ELECTRODE*

1963 ◽  
Vol 42 (3) ◽  
pp. 293-304 ◽  
Author(s):  
Edward W. Moore ◽  
Donald W. Wilson
Keyword(s):  
Body Fluids ◽  
Glass Electrode

A GLASS ELECTRODE VESSEL FOR THE DETERMINATION OF BLOOD pH

Science ◽  
1939 ◽  
Vol 90 (2330) ◽  
pp. 187-188 ◽  
Author(s):  
V. G. Behrmann ◽  
M. Fay
Keyword(s):  
Glass Electrode ◽  
Blood Ph

Site-Specific pKa Determination of Selenocysteine Residues in Selenovasopressin by Using 77Se NMR Spectroscopy

2011 ◽  
Vol 50 (50) ◽  
pp. 11952-11955 ◽  
Author(s):  
Mehdi Mobli ◽  
David Morgenstern ◽  
Glenn F. King ◽  
Paul F. Alewood ◽  
Markus Muttenthaler
Keyword(s):  
Nmr Spectroscopy ◽  
Site Specific ◽  
Pka Determination ◽  
77Se Nmr Spectroscopy

scholarly journals pKa determination of graphene-like materials: Validating chemical functionalization

2016 ◽  
Vol 467 ◽  
pp. 239-244 ◽  
Author(s):  
Elisa S. Orth ◽  
José G.L. Ferreira ◽  
Jéssica E.S. Fonsaca ◽  
Sirlon F. Blaskievicz ◽  
Sergio H. Domingues ◽  
...  
Keyword(s):  
Chemical Functionalization ◽  
Pka Determination

Photometric Determination of pH with a Single Standard and Calculation by Nomogram

1966 ◽  
Vol 12 (12) ◽  
pp. 849-870 ◽  
Author(s):  
Donald D Van Slyke ◽  
Lawrence V Hankes ◽  
Janis John Vitols
Keyword(s):  
Human Plasma ◽  
Photometric Determination ◽  
Glass Electrode ◽  
Phenol Red ◽  
Ph Values ◽  
Slow Fading ◽  
Standard Solution ◽  
Single Standard ◽  
Hasselbalch Equation

Abstract A method is described for construction of a nomogram, based on the Henderson Hasselbalch equation, with which photometric pH values can be calculated from the absorbance of an indicator in a sample and the absorbance of the indicator in a single standard solution. Thereby the necessity of preparing calibration curves from a series of standard solutions is avoided. The procedure is particularly convenient when the stock solution of the indicator is subject to slow fading, as in the case of phenol red. An application of the procedure to the photometric determination of the pH of human plasma is detailed and the results are compared with those obtained with a glass electrode.

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