Determination of Aqueous Formic and Acetic Acids by Purge-and-Trap Analysis with a Needle-Type Extraction Device and Gas Chromatography Barrier Discharge Ionization Detector.

A purge-and-trap method using a needle-type extraction device and a gas chromatography-barrier discharge ionization detector for the analysis of formic (FA) and acetic acids (AA) in aqueous samples is presented. An activated carbon-based adsorbent, Carboxen 1000, was employed as the extraction medium for the needle-type extraction device. The sampling time was 5 min for collecting headspace gas in a glass vial, including 10 mL of an aqueous sample. The detection limits for FA and AA with a headspace sampling volume of 100 mL were 3.3 and 2.0 mg L-1, respectively. Since the proposed method was based on purge-and-trap collection, it was suitable for the determination of aqueous FA and AA in complex matrices with simple and rapid sample preparation steps. The proposed method was applied to the determination of FA and AA in fruit juice samples and FA generated by the electrochemical reduction of carbon dioxide.