Determination of ethanol in beverages by flow injection, pervaporation and density measurements.

A fast, clean and easy to automate flow injection-pervaporation method for the determination of ethanol in different beverages using density measurements is proposed. The method is based on separation of the ethanol from the sample using a pervaporation module; the analyte being collected in water as acceptor liquid. The density of this water-alcohol mixture is measured at the detector. After optimisation by either a univariate or multivariate approach as required, a linear range between 0 and 40% was established. Then, the assessment of the method versus a reference one was studied in terms of repeatability (0.12% v/v), reproducibility (0.32% v/v), detection limit (0.11% v/v) and traceability. The sample throughput was 15 samples h(-1). The method was in agreement with the reference methods used in the European Union.