Determination of total sulphur and nitrogen in crude oil products by oxidative pyrolysis with detection using a metal-plated membrane electrode

Abstract

Following oxidative pyrolysis of the sample, the gaseous products are detected amperometrically at a gold-plated porous membrane electrode. In the determination of sulphur, the gaseous products are fed directly to the electrode; in the determination of nitrogen, the gaseous products are passed through a column containing PbO₂, in which SO₂ is removed and NO is converted into NO₂. The calibration graphs are linear in the ranges 7–1500 p.p.m. (S) and 5–1000 p.p.m. (N), the sensitivity of the determination is 8.4 nA (p.p.m.)^–1(S) and 4.2 nA (p.p.m.)^–1(N), and the detection limits are 2.5 p.p.m. (S) and 7.8 p.p.m. (N). The analysis time is 10–15 s.