SH/T 0409-1992 "Determination of Aromatic Hydrocarbons in Liquid Paraffin (Ultraviolet spectrophotometry) " is a Chinese Petrochemicals industry standard, specifying a method for the determination of aromatic hydrocarbons in liquid paraffins using an ultraviolet spectrophotometer. It is suitable for liquid paraffins with aromatic content ranging from 3 ppm to 5%, and the determination result is the average value of alkylbenzene and naphthalene. The method involves the determination of the maximum Absorbance near 285nm and 270nm in a 1cm quartz Colorimetric dish, including reagents, instrumentation requirements, and analytical steps. Provides experimental operation and result calculation for accurate, repeatability determination of aromatic hydrocarbons content in liquid paraffins.