A study of the Ca2+ – Arsenazo III system and its application to the spectrophotometric determination of free calcium in solution

1990 ◽  
Vol 68 (11) ◽  
pp. 1932-1936 ◽  
Author(s):  
Byron Kratochvil ◽  
Xi-Wen He
Keyword(s):  
Ionic Strength ◽  
Calcium Ion ◽  
Calcium Binding ◽  
Metal Ion ◽  
Arsenazo Iii ◽  
Free Calcium ◽  
Ionic Calcium ◽  
Free Metal ◽  
Free Metal Ion

A two-wavelength method was applied to the determination of free, ionic calcium with Arsenazo III in solutions containing calcium-binding ligands. By this procedure impurities in the indicator can be corrected for, thereby allowing the use of commercial indicator preparations with purities as low as 80%. Only a 1:1 complex with a conditional log stability constant of 4.28 ± 0.13 at pH 4.6 and ionic strength 0.1 was found under the conditions studied. Key words: free metal ion determination, calcium ion speciation, spectrophotometry, arsenazo III, ion increment method for speciation.

scholarly journals Determination of free metal ion concentrations with AGNES in low ionic strength media

2013 ◽  
Vol 689 ◽  
pp. 276-283 ◽  
Author(s):  
D. Aguilar ◽  
C. Parat ◽  
J. Galceran ◽  
E. Companys ◽  
J. Puy ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Metal Ion ◽  
Ion Concentrations ◽  
Low Ionic Strength ◽  
Free Metal ◽  
Free Metal Ion

Ion Exchange Complexing Resins as Sensors for the Determination of Free Metal Ion Concentration at a Low Level

2008 ◽  
Vol 26 (3) ◽  
pp. 301-320 ◽  
Author(s):  
Maria Pesavento ◽  
Antonella Profumo ◽  
Raffaela Biesuz ◽  
Giancarla Alberti
Keyword(s):  
Ion Exchange ◽  
Metal Ion ◽  
Ion Concentration ◽  
Low Level ◽  
Free Metal ◽  
Free Metal Ion

Prediction of Soluble Nickel Removal by Activated Sludge Using Free Metal Ion Concentrations

1987 ◽  
Vol 19 (3-4) ◽  
pp. 439-448 ◽  
Author(s):  
Jeppe S. Nielsen ◽  
Steve E. Hrudey ◽  
Frederick F. Cantwell
Keyword(s):  
Activated Sludge ◽  
Metal Ion ◽  
Municipal Sewage ◽  
Nickel Ion ◽  
Ion Concentrations ◽  
Untreated Sewage ◽  
Nickel Uptake ◽  
Nickel Removal ◽  
Free Metal ◽  
Free Metal Ion

Batch isotherm studies using spiked sewage samples containing a range of total soluble nickel concentrations typical of municipal sewage strongly suggested that it is the free (i.e. uncomplexed) nickel ion that is sorbed by activated sludge. Equations relating nickel uptake by activated sludge to free nickel ion concentrations and the extent of complexation in untreated sewage were developed and applied. Predicted and measured nickel removals generally agreed to within ± 30%.

Free metal ion availability is a major factor for tolerance and growth in Physcomitrella patens

2015 ◽  
Vol 110 ◽  
pp. 1-10 ◽  
Author(s):  
Stefan Sassmann ◽  
Wolfram Adlassnig ◽  
Markus Puschenreiter ◽  
Edwin Julio Palomino Cadenas ◽  
Mario Leyvas ◽  
...  
Keyword(s):  
Metal Ion ◽  
Physcomitrella Patens ◽  
Free Metal ◽  
Free Metal Ion

scholarly journals Mechanism for Increase in Intracellular Concentration of Free Calcium in Fertilized Sea Urchin Egg

1974 ◽  
Vol 63 (3) ◽  
pp. 374-388 ◽  
Author(s):  
Masahisa Nakamura ◽  
Ikuo Yasumasu
Keyword(s):  
Dissociation Constant ◽  
Sea Urchin ◽  
Calcium Ion ◽  
Calcium Binding ◽  
Intracellular Concentration ◽  
Sodium Ion ◽  
Free Calcium ◽  
Binding Ability ◽  
Sea Urchin Egg ◽  
Fertilized Egg

Intracellular free calcium concentration in the sea urchin egg was calculated to increase from 0.1 mM in an unfertilized egg to 1 mM in a fertilized egg 10 min after fertilization, based on measurement of the dissociation constant between free calcium and sea urchin egg homogenate. The dissociation constant between free calcium (dialyzable calcium) and homogenate of sea urchin eggs was measured by means of dialysis equilibrium. The dissociation constant of the unfertilized egg was about 10–4 M and that of the fertilized egg was about 10–3 M in three species of sea urchin, Hemicentrotus pulcherrimus, Anthocidaris crassispina, and Pseudocentrotus depressus. An increase in the dissociation constant of the unfertilized egg homogenate was observed after the addition of calcium ion at a concentration above 0.3 mM, the dissociation constant becoming the same as that observed in the fertilized egg homogenate after the administration of CaCl2 at a concentration above 1 mM. Sodium ion also caused a decrease in the calcium-binding ability of the unfertilized egg homogenate. Therefore, penetration of calcium ion or sodium ion upon fertilization might induce an increase in the dissociation constant and then intracellular concentration of free calcium would increase at fertilization. Almost all calcium-binding ability of the egg homogenate was found in the microsomal fraction, and the substance which bound calcium was thought to be protein in nature, since trypsin could decrease the level of calcium-binding substance in the homogenate of the eggs.

Sign in / Sign up

Export Citation Format

Share Document