1 This method is intended for the determination of sulphur in petroleum products, including lubricating oils containing additives and additive concentrates, and lubricating greases that cannot be burned completely in a wick lamp. The method is applicable to any petroleum product con-taining at least 0.1 percent sulphur and sufficiently low in volatility so that it is possible to weigh it accurately in an open sample boat.
1.2 This method is not applicable to samples containing elements that give residues, other than barium sulphate, which are insoluble in dilute hydro-chloric acid and would interfere in the precipitation step. These interfer-ing elements include iron, aluminium, calcium, Silicon and lead which are sometimes present in greases, lube oil additives or additive oils; other acid interfering insoluble materials are silica, molybdenum disulphide, asbestos, mica, etc. This method is also not applicable to used oils containing wear metals, and lead or Silicates from contamination.