Analysis of anthranilic acid by liquid chromatography.

Analytical methods for the assay of anthranilic acid and for determination of the impurities methyl anthranilate, anthranoylanthranilic acid and 3- and 4-aminobenzoic acid are described. A Microbondapak C18 column is used for both the assay and the impurity determination. The assay is based on isocratic development with a mobile phase of 35:65 v v methanol/pH-3 phosphate buffer, with benzoic acid as internal standard. The impurities are separated by gradient elution. The standard deviation of the assay method is about 1% and the limit of detection for the impurities is about 0.01%.

Determination of 2-mercaptobenzothiazole, tolyltriazole and benzotriazole in coolant formulations by liquid chromatography.

An analytical method based on high-performance liquid chromatography is suitable for the determination of corrosion inhibitors in coolant solutions based on ethylene glycol. An isocratic system of methanol/aqueous sodium acetate buffer is used with a Microbondapak C18 column. Recovery is 99+%, with a sensitivity of 0.05% w/w. No sample pretreatment is necessary. Analysis time is 15 min.