ASTM D4450-85(2019)

1.1 This test method is intended for the determination of zinc oxide and phosphorous acid content of the pigment commercially known as zinc hydroxy phosphite. The zinc content is determined by ethylenediaminetetraacetate (EDTA) titration and calculated as zinc oxide (ZnO), while the phosphorus content is determined colorimetrically and calculated as phosphorous acid (H₃PO₃).

1.2 The analytical procedures appear in the following order:

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

1.4 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

4.1 This test method may be used to confirm the stated zinc oxide and phosphorous acid content of zinc hydroxy phosphite pigment.