Sulphur dioxide can be determined at a sampling rate of 120 h-1, with amperometric detection after separation in a diffusion cell with a teflon membrane. At 25°C, the calibration graph shows two linear ranges, between 0.06 and 6 mg l-1 and 12 and 110 ml l- sulphur dioxide, with a detection limit of 0.03 mg l-1. At 50°C, the liner range is 04-5 mg l-1, with a detection limit of mg of l-1. The procedure has been applied to the determination of sulphur dioxide in wines. © 1986.