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Oregon Water Science Center

Alkalinity Calculator

Version 2.22

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Input acidimetric titration data and other information in the form below. Fields shown in red are required. The Alkalinity Calculator will analyze the titration curve and calculate the alkalinity or acid neutralizing capacity (ANC) of the sample using one or more of several different methods. Alkalinity is for filtered samples, while ANC is for unfiltered samples. The results will be displayed in tabular and graphical form.

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Send comments, questions, and suggestions to Please send me any datasets that appear to cause problems for the Alkalinity Calculator.

Sample Information
Site Name:
Site ID:
Collection Date: Collection Time:
Titration Information
Analysis Date: Analysis Time:
Sample Temperature: oC [help] Specific Conductance: µS/cm [help]
Sample Volume: mL
Filtered Sample?:
Acid Concentration:    Specify other acid conc.: N
Acid Lot Number: Acid Correction Factor: [help]
Acid Expiration Date:
Stirring Method:
Titration Type: Digital titrator
Buret titration
Titration Data: Enter two columns of data:
Data must be delimited by a comma or by one or more spaces.
You may "paste" your data into this form with the mouse.

Digital titrator: (counts)
Titrant volumes are specified in "counts" and are assumed
to come from a Hach digital titrator (800 counts per mL).

Buret titration: (mL)
Titrant volumes from a buret titration are specified in
milliliters (mL) of acid added.

Titration Analysis
Analysis Methods: Check one or more of the analysis methods you want to use:
  Inflection point method
  Gran function plot method
  Theoretical carbonate titration curve method
  Fixed endpoint:       Carbonate:     pH =
      Bicarbonate:   pH =
Speciation Method: The advanced speciation method will be used for the calculation of carbonate
and bicarbonate concentrations; the simple mass-balance speciation method is
deprecated and no longer available.
The calculation may take a minute or two.

Note: The specific conductance is used to estimate the ionic strength of the sample. Ionic strength and sample temperature are used to calculate the equilibrium dissociation constants of water and carbonic acid, which are then used in the calculation of hydroxide, carbonate, and bicarbonate concentrations. If you know the sample's temperature and specific conductance, please input them. If these data are unavailable, default values will be assumed.


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Page Last Modified: Monday - Aug 27, 2018 at 12:52:06 EDT