This document specifies a method using energy-dispersive X-ray fluorescence spectrometry for the determination of the sulfur content of petroleum products, such as naphthas, unleaded motor gasolines, middle distillates, residual fuel oils, base lubricating oils and components. The method is applicable to products with sulfur content in the range of a mass fraction of 0,03 % to a mass fraction of 5,00 %. This test method can be used for biofuel or biofuel blends.