ASTM International Standard Test Method for Determination of 4-Carboxybenzaldehyde and p -Toluic Acid in Purified Terephthalic Acid by Capillary Electrophoresis with Reverse Voltage Mode ASTM D7881-13

1.1 This test method2 covers the determination of 4-carboxybenzaldehyd e (4-CBA) and p-toluic acid (p-TOL) in purified terephthalic acid (PTA) by capillary electrophoresis (CE) with reverse voltage mode and UV detection. It is applicable for 4-CBA from 3 to 400 mg/kg and for p-TOL from 8 to 400 mg/kg, respectively. 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 and health practices and determine the applicability of regulatory limitations prior to use.