scholarly journals Determination of Alkalinity and dissociation constants of high salinity waters: use of F5BC titration function

2010 ◽  
Vol 35 (2) ◽  
pp. 79-87
Author(s):  
B.F Cavalcanti ◽  
L.C.L Agostinho ◽  
L Nascimento
Keyword(s):  
Natural Waters ◽  
Dissociation Constants ◽  
A Priori ◽  
Linear Regression Analysis ◽  
Liquid Junction ◽  
Carbonate System ◽  
Apparent Dissociation Constant ◽  
Saline Waters ◽  
Junction Potential

Measurements of parameters expressed in terms of carbonic species such as Alkalinity and Acidity of saline waters do not analyze the influence of external parameters to the titration such as Total free and associated Carbonic Species Concentration, activity coefficient, ion pairing formation and Residual Liquid Junction Potential in pH measurements. This paper shows the development of F5BC titration function based on the titrations developed by Gran (1952) for the carbonate system of natural waters. For practical use, samples of saline waters from Pocinhos reservoir in Paraiba were submitted to titration and linear regression analysis. Results showed that F5BC involves F1x and F2x Gran functions determination, respectively, for Alkalinity and Acidity calculations without knowing "a priori" the endpoint of the titration. F5BC also allows the determination of the First and Second Apparent Dissociation Constant of the carbonate system of saline and high ionic strength waters.

scholarly journals DETERMINATION OF ALKALINITY AND DISSOCIATION CONSTANTS OF HIGH SALINITY WATERS: USE OF F5BC TITRATION FUNCTION

2018 ◽  
Vol 35 (2) ◽  
pp. 79
Author(s):  
Bernadete F. Cavalcanti ◽  
Lourdes Cristina Lucena Agostinho ◽  
Luciano Nascimento
Keyword(s):  
Natural Waters ◽  
Dissociation Constants ◽  
A Priori ◽  
Linear Regression Analysis ◽  
Liquid Junction ◽  
Carbonate System ◽  
Ph Measurements ◽  
Apparent Dissociation Constant ◽  
Junction Potential

Measurements of parameters expressed in terms of carbonic species such as Alkalinity and Acidity of saline waters do not analyze the influence of external parameters to the titration such as Total free and associated Carbonic Species Concentration, activity coefficient, ion pairing formation and Residual Liquid Junction Potential in pH measurements. This paper shows the development of F5BC titration function based on the titrations developed by Gran (1952) for the carbonate system of natural waters. For practical use, samples of saline watersfrom Pocinhos reservoir in Paraiba were submitted to titration and linear regression analysis. Results showed that F5BC involves F1x and F2x Gran functions determination, respectively, for Alkalinity and Acidity calculations without knowing “a priori” the endpoint of the titration. F5BC also allows the determination of the First and Second Apparent Dissociation Constant of the carbonate system of saline and high ionic strength waters.

Direct potentiometric determination of sodium ion in blood. III. Influence of (bi)carbonate.

1985 ◽  
Vol 31 (4) ◽  
pp. 523-526 ◽  
Author(s):  
F B Boink ◽  
P Bijster ◽  
K L Vink ◽  
A H Maas
Keyword(s):  
Sodium Bicarbonate ◽  
Chloride Ion ◽  
Sodium Ion ◽  
Liquid Junction ◽  
Fresh Serum ◽  
Potentiometric Measurement ◽  
Bicarbonate Solutions ◽  
Carbonate Complexes ◽  
Junction Potential

Abstract We measured the emf of a sodium ion-selective electrode in NaCl-NaHCO3 solutions (160 mmol of Na+, 160-120 mmol of Cl-, and 0-40 mmol HCO3- per liter) with a home-built cell in steady-state after 10 min and with two commercial direct potentiometric analyzers about 20 s after the sample was introduced. Substitution of HCO3- for Cl- resulted in a small decrease in emf. We calculated the effect of chloride ion replacement by bicarbonate ion on the liquid-junction potential and found that this accounted only for one-third of the emf decrease. The exact composition of bicarbonate solutions is closely related to the pH. To control the formation of carbonate, we performed measurements with the home-built cell at two pH values (7.0 and 8.2), controlled by tonometry with carbon dioxide. From the differences in the slope of the emf vs the amount of bicarbonate added at the two pHs we calculated the thermodynamic association constants of the sodium bicarbonate and sodium carbonate complexes (KNaHCO3(0) = 0.53 and KNaCO3- = 24). We conclude that, for the direct potentiometric measurement of sodium ion, only fresh serum should be used, to avoid pH changes. Replacement of sodium chloride by sodium bicarbonate caused different results when emf was measured with commercial analyzers, owing to their short measuring time of about 20 s.

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