scholarly journals Apparatus for Rapid Electrometric Titration

1930 ◽  
Vol 16 (2) ◽  
pp. 519-527
Author(s):  
R. G. Neill
Keyword(s):  
Ph Value ◽  
Hydrogen Ion ◽  
Dilute Solutions ◽  
Ion Concentrations ◽  
Electrometric Titration

This apparatus was assembled at Millport for the electrometric titration of solutions which, being highly coloured, cannot well be titrated with an indicator. It may be used also for highly dilute solutions, unless they are so slightly buffered that their pH value is appreciably changed by the addition of a small quantity of quinhydrone. Measurement of hydrogen-ion concentrations at the quinhydrone electrode has also been attempted with the apparatus. The apparatus is suitable for use at sea.

scholarly journals THE COMPOSITION OF THE CELL SAP OF THE PLANT IN RELATION TO THE ABSORPTION OF IONS

1923 ◽  
Vol 5 (5) ◽  
pp. 629-646 ◽  
Author(s):  
D. R. Hoagland ◽  
A. R. Davis ◽  
Keyword(s):  
Cell Wall ◽  
Higher Plants ◽  
Ph Value ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Inorganic Elements ◽  
Dilute Solutions ◽  
Chemical Examination ◽  
Hydrogen Ion Concentration ◽  
Insoluble Form

1. Chemical examination of the cell sap of Nitella showed that the concentrations of all the principal inorganic elements, K, SO4, Ca, Mg, PO4, Cl, and Na, were very much higher than in the water in which the plants were growing. 2. Conductivity measurements and other considerations lead to the conclusion that all or nearly all of the inorganic elements present in the cell sap exist in ionic state. 3. The insoluble or combined elements found in the cell wall or protoplasm included Ca, Mg, S, Si, Fe, and Al. No potassium was present in insoluble form. Calcium was predominant. 4. The hydrogen ion concentration of healthy cells was found to be approximately constant, at pH 5.2. This value was not changed even when the outside solution varied from pH 5.0 to 9.0. 5. The penetration of NO3 ion into the cell sap from dilute solutions was definitely influenced by the hydrogen ion concentration of the solution. Penetration was much more rapid from a slightly acid solution than from an alkaline one. It is possible that the NO3 forms a combination with some constituent of the cell wall or of the protoplasm. 6. The exosmosis of chlorine from Nitella cells was found to be a delicate test for injury or altered permeability. 7. Dilute solutions of ammonium salts caused the reaction of the cell sap to increase its pH value. This change was accompanied by injury and exosmosis of chlorine. 8. Apparently the penetration of ions into the cell may take place from a solution of low concentration into a solution of higher concentration. 9. Various comparisons with higher plants are drawn, with reference to buffer systems, solubility of potassium, removal of nitrate from solution, etc.

Carbon Materials Based Ion Sensitive Field Effect Transistor (ISFET)

2017 ◽  
pp. 334-360
Author(s):  
Mohammad Javad Kiani ◽  
M. H. Shahrokh Abadi ◽  
Meisam Rahmani ◽  
Mohammad Taghi Ahmadi ◽  
F. K. Che Harun ◽  
...  
Keyword(s):  
Ph Value ◽  
Enzymatic Reaction ◽  
Electrical Measurement ◽  
Hydrogen Ion ◽  
Monolayer Graphene ◽  
Full Potential ◽  
Electrical Detection ◽  
Ion Concentrations ◽  
Detection Model ◽  
Ph Buffer

Graphene and SWCNT-based Ion Sensitive FET (ISFET) as a novel material with organic nature and ionic liquid gate is intrinsically sensitive to pH changes. pH is an important factor in enzymes stabilities which can affect the enzymatic reaction and broaden the number of enzyme applications. More accurate and consistent results of enzymes must be optimized to realize their full potential as catalysts accordingly. In this chapter, an appropriate structure to ISFET device is designed for the purpose of electrical measurement of different pH buffer solutions. Electrical detection model of each pH value is suggested using conductance modelling of monolayer graphene. In addition, ISFET based on nanostructured SWCNT is studied for the purpose of electrical detection of hydrogen ion concentrations. Electrical detection of hydrogen ion concentrations by modelling the conductance of SWCNT sheets is proposed. pH buffer as a function of gate voltage is assumed and sensing factor is defined. Finally, the proposed new approach improving the analytical model is compared with experimental data and shows good overall agreement.

scholarly journals The acidity of muscle during maintained contraction

1922 ◽  
Vol 93 (654) ◽  
pp. 406-410
Keyword(s):  
Manganese Dioxide ◽  
Hydrogen Ion ◽  
Ion Concentrations

In 1913, I described a method for recording changes in hydrogen-ion concentrations in tissues, by means of a manganese dioxide electrode in combination with a calomel electrode (1). By this method it was shown that the acidity of muscle probably increased at the same time as, or slightly before, the tension increased, and that the acidity decreased as the muscle relaxed (2). In a paper, which appeared as this note was being prepared for publication, Ritchie states that he has been unable to detect a variation in acidity by the use of manganese dioxide electrodes. I am inclined to think that his failure is due to the injury to the muscles on insertion of wires into its substance. In my own experiments the wires rest on the surface of the muscle.

scholarly journals THE RELATION OF THE PNEUMOCOCCUS TO HYDROGEN ION CONCENTRATION, ACID DEATH-POINT, AND DISSOLUTION OF THE ORGANISM

1919 ◽  
Vol 30 (4) ◽  
pp. 389-399 ◽  
Author(s):  
Frederick T. Lord ◽  
Robert N. Nye
Keyword(s):  
Hydrogen Ion ◽  
Ion Concentration ◽  
Direct Relation ◽  
Hydrogen Ion Concentration ◽  
Ion Concentrations ◽  
Cent Glucose ◽  
Fluid Media

1. In the growth and death of the pneumococcus in fluid media containing 1 per cent glucose the production of acid is the most important bactericidal factor. 2. 1 per cent glucose bouillon cultures of the pneumococcus allowed to grow and die out usually reach a final acidity of a pH of about 5.1. 3. At a hydrogen ion concentration of about 5.1 or higher, the pneumococcus does not survive longer than a few hours. 4. In hydrogen ion concentrations of about 6.8 to 7.4 the pneumococcus may live for at least many days. 5. In the intervening hydrogen ion concentrations, between 6.8 and 5.1, the pneumococcus is usually killed with a rapidity which bears a direct relation to the hydrogen ion concentration; i.e., the greater the acidity the more rapid is the death. 6. Cloudy suspensions of washed pneumococci in hydrogen ion concentrations varying from 8.0 to 4.0 show, after incubation, dissolution of organisms in lower hydrogen ion concentrations than about 5.0. This dissolution is most marked at about 5.0 to 6.0. Some dissolution also takes place toward the more alkaline end of the scale. No dissolution occurs at the most acid end of the scale.

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