精对苯二甲酸中苯甲酸、对羧基苯甲醛和对甲基苯甲酸含量的测定

Determination of Contents of Benzoic Acid, 4-Carboxy Benzaldehydeand p-Toluic Acid in Purified Terephthalic Acid

采用毛细管电泳法同时测定了精对苯二甲酸(PTA)中的苯甲酸(BA)、对羧基苯甲醛(4-CBA)和对甲基苯甲酸(p-TOL)的含量;考察了缓冲溶液的种类、缓冲溶液的pH、电泳时的电压、检测波长和进样时间对分离效率的影响。实验结果表明,选择3-(环己氨基)丙烷磺酸为缓冲溶液,在缓冲溶液的pH为10.0、电泳时的分离电压25kV、检测波长230nm、试样室温度25℃、进样压力25kPa、进样时间25s的条件下,PTA中BA,4-CBA,p-TOL的分离效果最佳,测定的结果准确。该方法具有精密度高、简单、快速和分离效率高等特点。

A new capillary electrophoresis method was adopted to determine the contents of benzoic acid （BA） ,4-carboxy benzaldehyde （4-CBA） and p-toluic acid （p-TOL） in purefied terephthalic acid （PTA）. Effects of buffer solution type, buffer solution pH, determination voltage, detection wavelength and sampling time on the separation efficiency were investigated. The optimal results obtained are： 3-（cyclohexylamino）-1-propanesulfonic acid as buffer solution, buffer solution pH 10.0, voltage 25 kV, detection wavelength 230 nm, column temperature 25 ℃, sampling time 25 s and sampling pressure 25 kPa. BA, p-TOL and 4-CBA in PTA are separated completely and determined accurately. The capillary electrophoresis method is accurate, simple, rapid and efficient for determination of contents of BA,4-CBA and p-TOL in PTA.