ASTM D8207-18

4.1 The presence of metals in PAT used for the production of polyester is undesirable because they may speed up or slow down the reaction and be impurities in the final product.

4.2 Determination of metals in PAT is often required. This test method is suitable for setting specifications and for use as an internal quality control tool where these products are produced or used.

1.1 This test method covers the determination of aluminum, chromium, cobalt, titanium, iron, manganese, molybdenum, sodium and nickel in purified terephthalic acid (PAT) by graphite furnace atomic absorption (GFAA) spectrometry. It is applicable to PAT samples containing sodium, chromium, cobalt, titanium, manganese, molybdenum and nickel over 0.004 mg/kg, and iron and aluminum over 0.054 mg/kg.

1.2 In determining the conformance of the test results using this method to applicable specification, results shall be rounded off in accordance with the rounding-off method of Practice E29.

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. Some specific hazards statements are given in 6.3, 6.10, 6.11, Section , and 9.1.

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.