This method is for estimating the dissolved oxygen in liquidhydrocarbons by electrochemical detection. The method is applicableto both on-line and laboratory analyses. The lower detection limitis 0.1 mass-ppm while the upper limit is dependent on thesolubility of oxygen in the specific sample. Carbon dioxide,ammonia and hydrogen sulfide at concentrations above 200, 300 and15-ppm (see Note 1), respectively, will interfere with the oxygendetermination. Materials that contaminate the membrane or volatilecomponents that are either oxidized, reduced, or react with theelectrodes will also interfere. The sampling system associated witha UOP process unit will be specified by UOP depending on thespecific process unit.