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The 'total inorganic carbon' (C_T, 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 anion. It is customary to express carbon dioxide and carbonic acid simultaneously as CO₂
★ . C_T is an important parameter when making measurements related to the pH of natural aqueous systems, and carbon dioxide flux estimates.
:C_T = [CO₂
★ ] + [HCO₃⁻] + [CO₃²⁻]
where,

★ C_T 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 intimately related by the following pH driven chemical equilibria:
:CO₂ + H₂O $$
ightleftarrows H₂CO₃ $$
ightleftarrows H⁺ + HCO₃⁻ $$
ightleftarrows H⁺ + CO₃²⁻
Total inorganic carbon is measured by the acidification 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, typically by infrared spectroscopy.

Contents

See also

See also

★ Total Organic Carbon

★ Total Alkalinity(A_T)

★ pH

★ carbon dioxide fugacity(f_CO2)

★ Total Organic Carbon Analyzer