Total inorganic carbon
Encyclopedia
The total inorganic carbon (CT, or TIC) or dissolved inorganic carbon (DIC) is the sum
of inorganic carbon
species in a solution
. The inorganic carbon species include carbon dioxide
, carbonic acid
, bicarbonate
anion, and carbonate
. It is customary to express carbon dioxide and carbonic acid simultaneously as CO2* . CT is an key parameter when making measurements related to the pH
of natural aqueous systems, and carbon dioxide flux estimates.
where,
Each of these species are related by the following pH driven chemical equilibria:
Total inorganic carbon is typically measured by the acid
ification of the sample which drives the equilibria
to CO2. This gas is then sparged
from solution and trapped, and the quantity trapped is then measured, usually by infrared spectroscopy
.
SUM
SUM can refer to:* The State University of Management* Soccer United Marketing* Society for the Establishment of Useful Manufactures* StartUp-Manager* Software User’s Manual,as from DOD-STD-2 167A, and MIL-STD-498...
of inorganic carbon
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
species in a solution
Solution
In chemistry, a solution is a homogeneous mixture composed of only one phase. In such a mixture, a solute is dissolved in another substance, known as a solvent. The solvent does the dissolving.- Types of solutions :...
. The inorganic carbon species include carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
, carbonic acid
Carbonic acid
Carbonic acid is the inorganic compound with the formula H2CO3 . It is also a name sometimes given to solutions of carbon dioxide in water, because such solutions contain small amounts of H2CO3. Carbonic acid forms two kinds of salts, the carbonates and the bicarbonates...
, bicarbonate
Bicarbonate
In inorganic chemistry, bicarbonate is an intermediate form in the deprotonation of carbonic acid...
anion, and carbonate
Carbonate
In chemistry, a carbonate is a salt of carbonic acid, characterized by the presence of the carbonate ion, . The name may also mean an ester of carbonic acid, an organic compound containing the carbonate group C2....
. It is customary to express carbon dioxide and carbonic acid simultaneously as CO2* . CT is an key parameter when making measurements related to the pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
of natural aqueous systems, and carbon dioxide flux estimates.
- CT = [CO2*] + [HCO3−] + [CO32−]
where,
- CT is the total inorganic carbon
- [CO2*] is the sum of carbon dioxide and carbonic acid concentrations ( [CO2*] = [CO2] + [H2CO3])
- [HCO3−] is the bicarbonate concentration
- [CO32−] is the carbonate concentration
Each of these species are related by the following pH driven chemical equilibria:
- CO2 + H2O H2CO3 H+ + HCO3− 2H+ + CO32−
Total inorganic carbon is typically measured by the acid
Acid
An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...
ification of the sample which drives the equilibria
Chemical equilibrium
In a chemical reaction, chemical equilibrium is the state in which the concentrations of the reactants and products have not yet changed with time. It occurs only in reversible reactions, and not in irreversible reactions. Usually, this state results when the forward reaction proceeds at the same...
to CO2. This gas is then sparged
Sparging (chemistry)
In chemistry, sparging, also known as gas flushing in metallurgy, is a technique which involves bubbling a chemically inert gas, such as nitrogen, argon, or helium, through a liquid. This can be used to remove dissolved gases In chemistry, sparging, also known as gas flushing in metallurgy, is a...
from solution and trapped, and the quantity trapped is then measured, usually by infrared spectroscopy
Infrared spectroscopy
Infrared spectroscopy is the spectroscopy that deals with the infrared region of the electromagnetic spectrum, that is light with a longer wavelength and lower frequency than visible light. It covers a range of techniques, mostly based on absorption spectroscopy. As with all spectroscopic...
.
See also
- AlkalinityAlkalinityAlkalinity or AT measures the ability of a solution to neutralize acids to the equivalence point of carbonate or bicarbonate. The alkalinity is equal to the stoichiometric sum of the bases in solution...
(total alkalinity; AT) - FugacityFugacityIn chemical thermodynamics, the fugacity of a real gas is an effective pressure which replaces the true mechanical pressure in accurate chemical equilibrium calculations. It is equal to the pressure of an ideal gas which has the same chemical potential as the real gas. For example, nitrogen gas ...
(carbon dioxide fugacity; fCO2) - Ocean acidificationOcean acidificationOcean acidification is the name given to the ongoing decrease in the pH and increase in acidity of the Earth's oceans, caused by the uptake of anthropogenic carbon dioxide from the atmosphere....
- pHPHIn chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
- Total organic carbonTotal organic carbonTotal organic carbon is the amount of carbon bound in an organic compound and is often used as a non-specific indicator of water quality or cleanliness of pharmaceutical manufacturing equipment....