pH is a measure of the hydrogen ion activity in water. It is a major parameter affecting the corrosivity and scaling properties of water, biological life in water and many applications of chemical process control. It is therefore important in water purification, use and waste treatment before release to the environment.

On-line pH measurement is preferred over laboratory measurement to obtain real time, continuous values for automatic control and monitoring purposes.

1. Scope

1.1 This test method covers the continuous determination of pH of water by electrometric measurement using the glass, the antimony or the ion-selective field-effect transistor (ISFET) electrode as the sensor.

1.2 This test method does not cover measurement of samples with less than 100 μS/cm conductivity. Refer to Test Method D 5128.

1.3 This test method does not cover laboratory or grab sample measurement of pH. Refer to Test Method D 1293.

1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.5 This standard does not purport to address all of the safety concerns, if any, 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.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

D1129 Terminology Relating to Water

D1193 Specification for Reagent Water

D1293 Test Methods for pH of Water

D2777 Practice for Determination of Precision and Bias of Applicable Test Methods of Committee D19 on Water

D3370 Practices for Sampling Water from Closed Conduits

D3864 Guide for Continual On-Line Monitoring Systems for Water Analysis

D5128 Test Method for On-Line pH Measurement of Water of Low Conductivity

Keywords

hydrogen ion; on-line; pH; process measurement; Automated procedures--water analysis; Hydrogen ion concentration; ISFET (ion-selective field-effect transducer); Online monitoring (in water analysis); pH--water; Process stream analysis;

ICS Code

ICS Number Code 71.040.50 (Physicochemical methods of analysis)

Citing ASTM Standards

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