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Standard Test Methods For Total And Dissolved Carbon Dioxide In Water

“Standard Test Methods for Total Dissolved Carbon Dioxide in Water” Annual Book of ASTM Standards. Philadelphia, PA: American Society of Testing and Materials. Current edition approved October 15, 1992.

ASTM D 513-88

This standard is issued under fixed designation D 513; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last re-approval. A superscript epsilon (€) indicates an editorial change since the last revision or re-approval.

  1. Scopes*
    1. 1.1 These test methods provide for the measurement of total or dissolved carbon dioxide present as carbon dioxide (CO2), carbonic acid, bicarbonate ion, and carbonate ion in water:
       

      Sections

      Test Method A (Gas Sensing Electrode)8 – 15
      Test Method B (CO2 Evolution, Coulometric Titration16 – 24
    2. Carbon dioxide may also be detected from carbonates present in particulates in samples.
    3. It is the user’s responsibility to ensure the validity of these test methods on waters of untested matrices.
    4. This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
    5. 1.5 Several test methods were discontinued from this standard in 1988. Refer to Appendix XI for Historical Information.
  2. Referenced Documents
    1. ASTM Standards:
      D1066 Practice for Sampling Steam2
      D1129 Definitions of Terms Relating to Water2
      D1192 Specification for Equipment for Sampling Water and Steam2
      D1193 Specification for Reagent Water2
      D1293 Test Methods for pH of Water2
      D2777 Practice for Determination of Precision and Bias of Applicable Methods of Committee D-19 on Water2
      D3370 Practices for Sampling Water2
      E 200 Practice for Preparation, Standardization, and Storage of Standard Solutions for Chemical Analysis2
  3. Definitions
    1. 3.1 For definitions of terms used in these test methods, refer to Definitions D 1129.
  4. Significance and Use
    1. Carbon dioxide is a major respiration product of plants and animals and a decomposition product of organic matter and certain minerals. The atmosphere averages about 0.04 volume percent of CO2. Surface waters generally contain less than 10 mg/L, except at local points of abnormal organic or mineral decomposition; however, underground water, particularly deep waters, may contain several hundred mg/L.
    2. When dissolved in water, CO2 contributes significantly to corrosion of water-handling systems. This is particularly troublesome in steam condensate systems. Loss of CO2 from an aqueous system can disturb the carbonate equilibrium and result in calcite encrustation of confining surfaces. Scaling of water heaters is a good example. Because of the delicate balance between corrosion and encrustation tendencies, much care must be given to control of CO2 and related species in water systems. Recarbonation of municipal supplies during final stages of softening and amine neutralization of steam condensate are applied for these purposes.
  5. Interferences
    1. General – Carbon dioxide is easily lost from solution during transit and storage of samples. It also is possible for total CO2 concentration to increase after sampling due to solution of finely divided calcium carbonate as a result of temperature or pressure changes.
  6. Purity of Reagents
    1. Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. 3 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination.
    2. Unless otherwise indicated, references to water shall be understood to mean water conforming to Type I of Specification D 1193. Additionally, for those test methods requiring water free of CO2, refer to Section 8.2 of Practice E 200.

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