HYDROGEN SULFIDE IN LIQUEFIED PETROLEUM GAS LPG BY LEAD ACETATE METHOD: ASTM D2420
(Equivalent Test Methods: IP 401, ISO 8819, DIN 51855 T3, and AFNOR M41-011)
EXPLANATION
Liquefied petroleum gas and its combustion products must not be unduly corrosive to the materials that they come in contact with. Hence, the measurement of hydrogen sulfide in LPG is important. Also, in some specifications, for example, Specification ASTM D1835, the odor of the gases must not be objectional. The sensitivity of the test is about 4 mg/m3 of gas. Methyl mercaptan, if present, produces a transitory yellow stain on the lead acetate paper which, however, fades completely in less than 5 min. Other sulfur compounds present in LPG do not interfere.
TEST SUMMARY
The vaporized gas is passed over moist lead acetate paper under controlled conditions. Hydrogen sulfide reacts with lead acetate to form lead sulfide resulting in a stain on the paper varying in color from yellow to black, depending on the amount of hydrogen sulfide present.
TEST PRECISION
This is a pass-fail test and no statement regarding precision can be made.
This test method has no bias.
