GB/T 11136-1989 introduces the method of determining the bromine index of petroleum hydrocarbons by the potentiometric Titrimetric method. The standard specifies the applicable range of petroleum hydrocarbons samples, and describes the principle of determining the bromine index based on the titration end point based on potential changes. Specifies the equipment required for the experiment, such as Potentiometric titrator, and reagent materials. Detailed description of Sample Handling, titration operation steps, including titrant addition method, potential data recording, etc. With this standard, the bromine index of petroleum hydrocarbons can be accurately determined, providing key data for evaluating the unsaturation degree and mass of petroleum hydrocarbons, and assisting the production and quality control of petroleum-related industries.