title: Chromatographic fingerprints of industrial toluic acids established for their quality control.
abstract: The chromatographic fingerprints of industrial o-toluic acid, m-toluic acid and p-toluic acid have been established by HPLC-UV detection according to their impurity groups. HPLC separation of all relative substances involved in the groups was developed on a Kromasil C(18) column by using methanol-water-NH(4)Ac-HAc buffer (100mM, pH 4.70) 15/65/20 (v/v/v) as the mobile phase at a flow rate of 1.5mL/min, and detection was operated by UV adsorption at a wavelength of 254nm. The ultraviolet spectra corresponding to each chromatographic peak were also recorded for further identification of all components. Whether the limits of relative impurities residues in a toluic acid product are qualified or not can be intuitively estimated by analyzing its chromatogram with comparison to the fingerprint. This protocol has successfully provided some Chinese manufacturers with a simple and feasible method for quality control of toluic acids for industrial use.
authors.affiliation: Key Laboratory of Analytical Chemistry for Life Science (Education Ministry of China), School of Chemistry and Chemical Engineering & Center of Materials Analysis, Nanjing University, 22 Hankou Road, Nanjing 210093, PR China.
authors.forename: Hongzhen
authors.initials: H
authors.lastname: Lian
authors.forename: Yuna
authors.initials: Y
authors.lastname: Wei