Determination of 2,6-di-tert-butylphenol in Irganox 1425

An ion suppression reversed phase high performance liquid chromatography method has been developed for the determination of 2,6-di-tert-butylphenol in Irganox 1425. Separation was carried out on a Welch Material Ultimate XB-C18 column (5 μm, 150 mm × 4.6 mm), using methanol–water (0.1 % HClO4) (75/25, v/v) mixture as the mobile phase in an isocratic elution. Detection was performed by UV absorption at a wavelength of 275 nm, and the limit of detection was 0.2 μg/mL. The method presented excellent repeatability and precision with both intra- and inter-day relative standard deviations (RSDs) of less than 2.0 %, as well as satisfactory accuracy with the recovery of 98.7–102.3 %, and therefore can be applied for the quality control analysis of Irganox 1425 industrial product.