Standard Test Method for Electrical Conductivity and Resistivity of a Flowing High Purity Water Sample

Importancia y uso:

5.1 Conductivity measurements are typically made on samples of moderate to high ionic strength where contamination of open samples in routine laboratory handling is negligible. Under those conditions, standard temperature compensation using coefficients of 1 to 3 % of reading per degree Celsius over wide concentration ranges is appropriate. In contrast, this test method requires special considerations to reduce trace contamination and accommodates the high and variable temperature coefficients of pure water samples that can range as high as 7 % of reading per degree Celsius. In addition, measuring instrument design performance must be proven under high purity conditions.

5.2 This test method is applicable for detecting trace amounts of ionic contaminants in water. It is the primary means of monitoring the performance of demineralization and other high purity water treatment operations. It is also used to detect ionic contamination in boiler waters, microelectronics rinse waters, pharmaceutical process waters, etc., as well as to monitor and control the level of boiler and power plant cycle chemistry treatment chemicals. This test method supplements the basic measurement requirements for Test Methods D1125, D2186, and D4519.

5.3 At very low levels of alkaline contamination, for example, 0–1 μg/L NaOH, conductivity is suppressed, and can actually be slightly below the theoretical value for pure water. (1 and 2)4 Alkaline materials suppress the highly conductive hydrogen ion concentration while replacing it with less conductive sodium and hydroxide ions. This phenomenon is not an interference with conductivity or resistivity measurement itself but could give misleading indications of inferred water purity in this range if it is not recognized.

Subcomité:

D19.03

Referida por:

D5196-06R18, D3087-17, D7513-17, D6504-11R24, D4266-17, D1125-23, D6302-98R17, D5127-13R18, D1125-23, D1193-06R18, D1193-06R18, D1193-06R18, D1193-06R18, D1193-06R18

Volúmen:

11.01

Número ICS:

13.060.60 (Examination of physical properties of water)

Palabras clave:

cation; conductivity; high purity water measurements; resistivity; specific conductance; specific resistance;