【Abstract】 Micro-amount terephthalic acid and 4-carboxybenzaldehyde in p-toluic acids were determined by a reversed-phase ion suppression chromatography.The separation was carried out on a C₁₈column（4.6mm i.d.×150mm）with methanol-water（70∶30）as the mobile phase at a flow rate of 0.8ml/min and with H₃PO₄ as an inhibitor.The detection wavelength was 240 nm.The relative standard deviation of terephthalic acid and 4-carboxybenzaldehyde are less than 3% and 2%,respectively.The average recoveries were 102.9% and 103.2%,respectively.The detection limit were 0.25 ng and 0.45 ng,respectively.更多还原