1.1 本试验方法包括测定4-羧基苯甲醛（4-CBA）和

-甲苯(

-TOL）通过反相高效液相色谱法（HPLC）在纯化的对苯二甲酸（PTA）中。此方法适用于4-CBA和

-TOL上限为500 mg/kg，但是可以适用于更宽的范围。 1.2 在使用该方法确定试验结果是否符合适用规范时，应根据实践中的舍入方法对结果进行舍入 E29 . 1.3 以国际单位制表示的数值应视为标准。本标准不包括其他计量单位。 1.4 本标准并不旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 有关具体的危险说明，请参阅第节 7. . 1.5 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。 ====意义和用途====== 4.1 4-CBA和

-用于生产聚酯的PTA中的TOL是不希望的，因为它们会影响PET质量（例如导致纤维断裂）、聚合过程，并且4-CBA由于热不稳定性而使聚合物着色。 4.2 确定4-CBA的量和

-通常需要PTA制造过程中剩余的TOL。该测试方法适用于设定规格，并用作生产或使用这些产品的内部质量控制工具。

1.1 This test method covers the determination of the 4-Carboxybenzaldehyde (4-CBA) and p -Toluic acid ( p -TOL) in purified terephthalic acid (PTA) by reverse phase high performance liquid chromatography (HPLC). This method is applicable for 4-CBA and p - TOL with an upper limit of 500 mg/kg, respectively, but may be applicable to a wider range. 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. For specific hazard statements, see Section 7 . 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. ====== Significance And Use ====== 4.1 The presence of 4-CBA and p -TOL in PTA used for the production of polyester is undesirable because they can affect the PET quality (such as contribute to fiber breaks), the polymerization process, and 4-CBA imparts coloration to the polymer due to thermal instability. 4.2 Determining the amount of 4-CBA and p -TOL remaining from the manufacture of PTA 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 are used.