ASTM D1123 standard test methods for water in engine coolant concentrate
ASTM D1123 standard test methods for water in engine coolant concentrate by the Karl Fischer reagent method
1. Scope
1.1 These test methods cover the determination of the water present in new or unused glycol-based coolant concentrates using a manual (Test Method A) or an automatic (Test Method B) coulometric titrator procedure.
1.2 Many carbonyl compounds react slowly with the Fischer reagent, causing a fading end point and leading to high results. A modified Fischer reagent procedure is included that minimizes these undesirable and interfering reactions.
1.3 This standard does not purport to address all of the safety problems, 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. For specific hazards statements see Sections 8 and 16.
2. Referenced Documents
2.1 ASTM Standards:
D156 Test Method for Saybolt Color of Petroleum Products (Saybolt Chromometer Method)
D1176 Test Method for Sampling and Preparing Aqueous Solutions of Engine Coolants or Antirusts for Testing Purposes
D1193 Specification for Reagent Water
E 203 Test Method for Water Using Karl Fischer Reagent
3. Terminology
3.1 Definitions:
3.1.1 color end point - that point during the titration when the color change from yellow to orange-red is sharp and easily repeated. The orange-red color must persist for at least 30 s in order to indicate an end point.
3.1.1.1 Discussion - View the color by transmitted daylight or by transmitted light from an artificial daylight lamp, such as one that complies with the specification given in Test Method D156.
3.1.2 instrument end point - for the purpose of these tests, that point in the titration when two small platinum electrodes, upon which a potential of 20 to 50 mV has been impressed, are depolarized by the addition of 0.05 mL of Fischer reagent (6 mg of water/mL), causing a change of current flow of 10 to 20 µA that persists for at least 30 s.
3.1.2.1 Discussion - This end point is sometimes incorrectly called the "dead stop", which is the reverse of the above.
