Microextraction Preconcentration of Chloroacetic Acids with the Flotation Separation of the Extract

A procedure is developed for liquid–liquid microextraction preconcentration of mono-, di-, and trichloroacetic acids (CAAs) with the flotation separation of the extract. Methyl tert-butyl ether, emulsified by ultrasonic treatment, is used as an extractant. Preconcentration is carried out in a 27-mL ampoule, equipped with a capillary for the selection of microquantities of the extract. The ion-chromatographic determination of CAAs is carried out after replacing the organic matrix extract with water. The advantages of the flotation method of demulsification versus the centrifuge one are shown: coefficients of concentration of chloroacetic acids are 2–2.2 times higher; limits of detection for CAAs are lowered to 5 × 10–4–4 × 10–3 mg/L, and extraction time is reduced by a factor of 3.3.