Difference between revisions of "Oxygen solubility"

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Oxygen solubility

Description

The oxygen solubility, S_O₂ [µM/kPa], expresses the oxygen concentration in solution in equilibrium with the oxygen pressure in a gas phase, as a function of temperature and composition of the solution. The inverse of oxygen solubility is related to the activity of dissolved oxygen. The oxygen solubility, S_O₂, depends on temperature and the concentrations of solutes in solution, whereas the dissolved oxygen concentration at equilibrium with air, c_O₂^*, depends on S_O₂, barometric pressure and temperature. S_O₂ in pure water is 10.56 µM/kPa at 37 °C and 12.56 µM/kPa at 25 °C. At standard barometric pressure (100 kPa), c_O₂^* is 207.3 µM at 37 °C (19.6 kPa partial oxygen pressure) or 254.7 µM at 25 °C (20.3 kPa partial oxygen pressure). In MiR05 and serum, the corresponding saturation concentrations are 191 and 184 µM at 37 °C or 234 and 227 µM at 25 °C. See also: Oxygen solubility factor

Abbreviation: S_O₂ [µM/kPa]

Reference: MiPNet06.03 POS-calibration-SOP, Forstner 1983 POS

Communicated by Gnaiger E 2010-10-21 (last update 2020-02-17)

Oxygen solubility in gas (g) versus aqueous solution (aq)

Solubility is defined as concentration per pressure,

Eq. 1:  S_G(g) = c/p

A distinction has to be made between solubility of an ideal gas in the gas phase S_G(g), and a real gas in the aqueous phase, such as S_O₂(aq).

The gas law relates pressure to concentration in an ideal gas,

Eq. 2:  p = c·RT

Substituting in Eq. 2 from Eq. 1 c = S_G(g)·p, and solving for S_G(g),

Eq. 3:  S_G(g) = RT^-1

The following constants are inserted into Eq. 3 (Tab. 1):

(a) The gas constant, R, equals 8.314462618 J·mol^-1·K^-1.
(b) Temperature in °C is converted to absolute temperature as T[K] = T[° C] + 273.15.

Then the solubility of an ideal gas in the gas phase, S_G(g) [µM·kPa^-1], is compared in Tab. 1 to the oxygen solubility in pure water, S_O₂(aq) (for which normally the abbreviated symbol S_O₂ is used). The ratio of the oxygen solubility in gas to aqueous solution, (g)/(aq), increases from 20 at 0 °C to a factor of 37 at 37 °C (Table 1). Importantly, the chemical potentials of oxygen in the gas and aqueous phase are equal at equilibrium, when concentrations in the aquesous phase vary 20- to >40-fold, taking into account that the aqueous phase under experimental conditions with mitochondria or cells is a physiological salt solution, in which the oxygen solubility is further reduced (see Oxygen solubility factor).

The definition of activity in the gas and aqueous phase depends on the definition of the standard state. In this context, it is 'advantageous to choose the standard state of unit activity as that in which the partial pressure of the gas is unity at a given temperature' (Hitchman and Gnaiger 1983).

Bioblast links: Concentration and pressure - >>>>>>> - Click on [Expand] or [Collapse] - >>>>>>>

Concentration

» Volume

» Activity

» Concentration

» Density

» Mole

» Molar mass

Pressure

» Barometric pressure

» Chemiosmotic pressure

» Gas pressure

» Osmotic pressure

» Oxygen pressure

» pascal

» Pressure

Solubility = concentration/pressure

» Solubility

» Solubility factor

» Oxygen solubility

General

» Boltzmann constant

» Energy

» Force

» Gas constant

» Work

Related keyword lists

» Keywords: Oxygen signal

» Keywords: Normalization

Bioblast links: Oxygen signal - >>>>>>> - Click on [Expand] or [Collapse] - >>>>>>>

Specific

O2k-Procedures

» High signal at zero oxygen

» POS calibration - static

» POS calibration - dynamic

MiPNet O2k-Procedures

» POS-calibration

» O2k-Manual: POS-service

» O2k-cleaning

» O2k-Series G and DatLab 6: Calibration

General

» Oxygen, dioxygen, O₂

» Oxygen calibration - DatLab

» Oxygen solubility

» Oxygen solubility factor

» Oxygen pressure

» Concentration

» Activity

» Pressure - Pascal

» Barometric pressure

» High-resolution respirometry

» OroboPOS

» Polarographic oxygen sensor

» MitoFit Quality Control System

» Sensitivity

Other keyword lists

» Keywords: Concentration and pressure

References

Hitchman ML, Gnaiger E (1983) A thermodynamic consideration of permeability coefficients of membranes. In: Polarographic Oxygen Sensors. Aquatic and Physiological Applications. Gnaiger E, Forstner H (eds), Springer, Berlin, Heidelberg, New York:31-6. - »Bioblast link«

MitoPedia concepts: MiP concept, Ergodynamics

MitoPedia methods: Respirometry

MitoPedia O2k and high-resolution respirometry: DatLab

MitoPedia topics: Media for respirometry

@@ Line 1: / Line 1: @@
 {{MitoPedia
 |abbr=''S''<sub>O<sub>2</sub></sub> [µM/kPa]
-|description=The '''oxygen solubility''', ''S''<sub>O<sub>2</sub></sub> [µM/kPa], expresses the oxygen concentration in solution in equilibrium with the [[oxygen pressure]] in a gas phase, as a function of temperature and composition of the solution.  ''S''<sub>O<sub>2</sub></sub> is 10.56 µM/kPa in pure water at 37 °C.  At standard [[barometric pressure]] (100 kPa), the oxygen concentration at air saturation is 207.3 µM at 37 °C (19.6 kPa partial oxygen pressure).  In [[MiR05]] and serum, the corresponding saturation concentrations are 191 and 184 µM. The oxygen solubility depends on temperatue and the concentrations of solutes in solution.
+|description=The '''oxygen solubility''', ''S''<sub>O<sub>2</sub></sub> [µM/kPa], expresses the oxygen concentration in solution in equilibrium with the [[oxygen pressure]] in a gas phase, as a function of temperature and composition of the solution. The inverse of oxygen solubility is related to the [[activity]] of dissolved oxygen. The oxygen solubility, ''S''<sub>O<sub>2</sub></sub>, depends on temperature and the concentrations of solutes in solution, whereas the dissolved oxygen concentration at equilibrium with air, ''c''<sub>O<sub>2</sub></sub><sup>*</sup>, depends on ''S''<sub>O<sub>2</sub></sub>, barometric pressure and temperature. ''S''<sub>O<sub>2</sub></sub> in pure water is 10.56 µM/kPa at 37 °C and 12.56 µM/kPa at 25 °C. At standard [[barometric pressure]] (100 kPa), ''c''<sub>O<sub>2</sub></sub><sup>*</sup> is 207.3 µM at 37 °C (19.6 kPa partial oxygen pressure) or 254.7 µM at 25 °C (20.3 kPa partial oxygen pressure). In [[MiR05]] and serum, the corresponding saturation concentrations are 191 and 184 µM at 37 °C or 234 and 227 µM at 25 °C. See also: [[Oxygen solubility factor]]
-See also: [[Oxygen solubility factor]]
 |info=[[MiPNet06.03 POS-calibration-SOP]], [[Forstner 1983 POS]]
 }}
+ Communicated by [[Gnaiger E]] 2010-10-21 (last update 2020-02-17)
+== Oxygen solubility in gas (g) versus aqueous solution (aq) ==
+:::: Solubility is defined as [[concentration]] per [[pressure]],
+ <big>'''Eq. 1''':  ''S''<sub>G</sub>(g) = ''c''/''p''</big>
+:::: A distinction has to be made between solubility of an ideal gas in the gas phase ''S''<sub>G</sub>(g), and a real gas in the aqueous phase, such as ''S''<sub>O<sub>2</sub></sub>(aq).
+:::: The gas law relates pressure to concentration in an ideal gas,
+ <big>'''Eq. 2''':  ''p'' = ''c''·''RT''</big>
+:::: Substituting in Eq. 2 from Eq. 1 ''c'' = ''S''<sub>G</sub>(g)·''p'', and solving for ''S''<sub>G</sub>(g),
+ <big>'''Eq. 3''':  ''S''<sub>G</sub>(g) = ''RT''<sup>-1</sup></big>
+[[File:Solubility-gaslaw.png|right|400px|Table 1]]
+:::: The following constants are inserted into Eq. 3 (Tab. 1):
+::::* (a) The [[gas constant]], ''R'', equals 8.314462618 J·mol<sup>-1</sup>·K<sup>-1</sup>.
+::::* (b) Temperature in °C is converted to absolute temperature as ''T''[K] = ''T''[° C] + 273.15.
+:::: Then the solubility of an ideal gas in the gas phase, ''S''<sub>G</sub>(g) [µM·kPa<sup>-1</sup>], is compared in Tab. 1 to the oxygen solubility in pure water, ''S''<sub>O<sub>2</sub></sub>(aq) (for which normally the abbreviated symbol ''S''<sub>O<sub>2</sub></sub> is used). The ratio of the oxygen solubility in gas to aqueous solution, (g)/(aq), increases from 20 at 0 °C to a factor of 37 at 37 °C (Table 1). Importantly, the chemical potentials of oxygen in the gas and aqueous phase are equal at equilibrium, when concentrations in the aquesous phase vary 20- to >40-fold, taking into account that the aqueous phase under experimental conditions with mitochondria or cells is a physiological salt solution, in which the oxygen solubility is further reduced (''see'' [[Oxygen solubility factor]]).
+:::: The definition of activity in the gas and aqueous phase depends on the definition of the standard state. In this context, it is 'advantageous to choose the standard state of unit activity as that in which the partial pressure of the gas is unity at a given temperature' ([[Hitchman 1983 POS Membrane |Hitchman and Gnaiger 1983]]).
 {{Keywords: Concentration and pressure}}
-{{Template:Keywords: Oxygen signal}}
+{{Keywords: Oxygen signal}}
+== References ==
+::::# Hitchman ML, Gnaiger E (1983) A thermodynamic consideration of permeability coefficients of membranes. In: Polarographic Oxygen Sensors. Aquatic and Physiological Applications. Gnaiger E, Forstner H (eds), Springer, Berlin, Heidelberg, New York:31-6. - [[Hitchman 1983 POS Membrane |»Bioblast link«]]
 {{MitoPedia concepts