The oxygen flask method in combination with potentiometric titration with a standard Ag⁺ solution is used for microanalysis of organic chloro-and bromo-compounds.Chlorine ion-selective electrode (or a wire of Ag-AgCl (electrod)) is used as the end point detector in 90% acetone (V/V).Potentials are measured vs.SCE(KNO₃) for glass electrode).Thus, a sharp end point will be directly shown on the instrument.The method has the advantages of being simple and rapid and accurate to ±0.3% of absolute error.The presence of N, F, S, P, As, B, Si did not interfere with the organic chlorine and bromine determination.Also, this procedure is useful for the microdetermination of organio chlorine in the presence of bromine or/and iodine.