Development of High Purity Dibutyl Sulfide Certified Reference Material (NMIJ CRM 4221-A) for Determination of Sulfur in Fuels

To obtain reliable analytical values of sulfur in fuels, sulfur standard solutions must be prepared accurately. A sulfur certified reference material in high purity sulfur compound, NMIJ CRM 4221-a (dibutyl sulfide), has been issued by National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology (NMIJ, AIST). The purity of dibutyl sulfide was determined by a freezing point depression method and a mass balance method. The certified value for sulfur content (mass fraction) was based on the purity, molecular weight, atomic weight, and impurities containing sulfur. The certified value (sulfur content) and its expanded uncertainty (k = 2) are 0.21919 kg kg−1 and 0.00006 kg kg−1, respectively. The details of procedures for determination of the certified value are reported here.