1.1 本试验方法包括使用气相色谱法和硫选择性检测法测定精制苯中的噻吩。 1.2 本试验方法适用于AED苯中0.02 mg至2.18 mg噻吩/kg（mg/kg）、PFPD 0.03 mg/kg至1.87 mg/kg、SCD 0.03 mg/kg至2.11 mg/kg的噻吩测定。可以通过改变样品进样体积、分流比、校准范围或用不含噻吩的溶剂稀释样品来扩展测试方法的范围。 1.3 以下内容适用于确定使用该方法的测试结果是否符合适用的质量标准，结果应按照惯例的四舍五入方法进行四舍五入 E29 . 1.4 以SI单位表示的值将被视为标准值。本标准不包括其他计量单位。 1.5 本标准并不旨在解决与其使用相关的所有安全性问题（如果有）。本标准的使用者有责任在使用前建立适当的安全、健康和环境实践并确定法规限制的适用性。 有关具体危害陈述，请参见章节 8 . 1.6 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）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====== 5.1 由于痕量分析的困难，气相色谱法准确测定苯中痕量噻吩涉及特殊的分析问题。这些问题源于需要测量的低浓度水平、分析所需的色谱柱和检测器的类型以及苯基质的潜在干扰。 5.2 本试验方法适用于精制苯中噻吩的测定，符合质量标准中描述的质量标准 D2359 , D4734 ，和 D5871 并且如果用户已经采取了如文中所述的必要预防措施，则可以适用于其他等级的苯。 5.3 该测试方法是作为测试方法的替代技术而开发的 D4735 .

1.1 This test method covers the determination of thiophene in refined benzene using gas chromatography and sulfur selective detection. 1.2 This test method is applicable to the determination of thiophene at levels of 0.02 mg to 2.18 mg thiophene per kg in benzene (mg/kg) on the AED, 0.03 mg/kg to 1.87 mg/kg on the PFPD, and 0.03 mg/kg to 2.11 mg/kg on the SCD. The range of the test method may be extended by modifying the sample injection volume, split ratios, calibration range, or sample dilution with thiophene-free solvent. 1.3 The following applies for the purposes of determining the conformance of the test results using this method to applicable specifications, results shall be rounded off in accordance with the rounding-off method of Practice E29 . 1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.5 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 8 . 1.6 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 ====== 5.1 Accurate gas chromatographic determination of trace levels of thiophene in benzene involves special analytical problems because of the difficulties of trace level analysis. These problems arise from the low concentration levels that need to be measured, the type of column and detector needed for analysis, and the potential interference from the benzene matrix. 5.2 This test method was found applicable for determining thiophene in refined benzene conforming to the specifications described in Specifications D2359 , D4734 , and D5871 and may be applicable toward other grades of benzene if the user has taken the necessary precautions as described in the text. 5.3 This test method was developed as an alternative technique to Test Method D4735 .