The purpose of this standard is to describe an X-ray fluorescence method for the determination of sulfur in gasoline, distillates, fuel oils, residual distillation products, base lubricating oils and gasoline free of lead and other components. The method is valid in the range of 0.01% to 5% by weight of sulfur. Samples containing additives with heavy metals, alkyl lead compounds, etc. interfere. Silicon, phosphorus, calcium, potassium, and halides interfere if present in concentrations greater than a few hundred parts per million.