Determination of benzoic acid in milk by solid-phase extraction and ion chromatography with conductivity detection

A simple, fast, precise and eco-friendly method, based on ion chromatography （IC） with a suppressed conductivity detector, was proposed for the determination of benzoic acid （BA） in milk in this paper. The chromatographic separation was accomplished by using an anion exchange column eluted with 3.2 mmol/L aqueous Na2C03 and 1.0 mmol/L aqueous NaHCO3 at a flow-rate of 0.7 mL/min. The method validation experiment provided excellent results with respect to linearity （correlation coefficient up to 0.9997）, limit of detection （0.1 ug/L）, recovery values （ranging from 88.0% to 93.0%） and relative standard deviation （RSD） （below 2.2%, n = 7）.