Determination of Pyromellitic Acid and Impurities by HPLC

A HPLC analysis method for pyromellitic acid and its impurities was established by optimization of the operation condition of chromatogrophy.The optimized parameters were that column temperature was 35 ℃,acetonitrile-0.1% (φ) phosphoric acid solution (25+75) of pH 1.9 was the mobile phase,flow rate was 1.0 mL·min-1,detection wavelength was 237 nm.External standard method was used for quatification.A baseline separation (separation>2) for pyromellitic acid and its impurities was achieved.Linear relationship was found between peak area and the mass concentration,with detection limits in the range of 0.03-0.08 mg·L-1 and the lower limits of determination in the range of 0.07-0.22 mg·L-1.RSD (n=5) was less than 2%.