(Equivalent Test Methods: IP 61, DIN 51577, and AFNOR T60-109)
EXPLANATION
This test method is applicable to any petroleum product sufficiently low in volatility that it can be weighed accurately in an open sample boat and containing at least 0.1 % sulfur. This test method is not applicable to samples containing elements that give residues, other than barium sulfate, which are insoluble in dilute hydrochloric acid and would interfere in the precipitation step. These interfering elements include iron, aluminum, calcium, silicon, and lead, which are sometimes present in greases and lube additives. Other insoluble materials that interfere are silica, molybdenum disulfide, asbestos, mica, etc. The test method is not applicable to used oils containing wear metals, and lead or silicates from contamination. The samples that are excluded here can be analyzed by Test Method ASTM D1552.
TEST SUMMARY
The sample is oxidized by combustion in a bomb containing oxygen under pressure. The sulfur in the sample is converted to sulfate, and from the bomb washings is gravimetrically determined as barium sulfate.
TEST PRECISION
Results from one single laboratory on NIST SRMs were found to be 0.05 mass % higher than the accepted reference values.