Comparing alpha spectra obtained either with LSC or with the method using uranium adsorbing films . Spectra are for the same French mineral water and for the same counting time (20'000 s). The water contains about 1 Bq/l 238 U and about 2 Bq/l 234 U. (units) Upper spectrum : 50 ml sample acidified to pH 2.5 , boiled, evacuated and released with argon, 2.5 ml " ALPHAEX "- scintillator added to 10 ml of this solution , shaken for 2 min., 1ml of the scintillator measured with a PERALS -Spektrometer ( McDowell and McDowell, 1994 ). Lower spectrum : 100 ml sample acidified to pH 2.5, a 25mm x 25mm uranium adsorbing film exposed for 20h (stirred), dried and then measured with a 900 mm 2 Si-surface-barrier alpha detector, detector-sample distance approx. 10 mm. Error bars are ±1 s - counting statistics.