Determination of trace sulfur in organic compounds by activated Raney nickel desulfurization method with non-dispersive gas detection system

Abstract

A sensitive and precise method for the determination of trace amounts of total sulfur in organic mixtures is described. With this method bonded sulfur is reacted with activated Raney nickel and is reduced to nickel sulfide at 70 °C. Then, the residue is separated on a filter paper and pyrolysed by induction furnace technique for generation of SO₂ which is then detected by a non-dispersive gas detector. This method is ideally suited for the determination of trace amounts of sulfur in petroleum distillates, organic solvents and pharmaceutical species such as antibiotics and vitamins. The effect of olefines and the amount of Raney nickel on the sensitivity and accuracy of the results is investigated. The 3ς detection limit was 100 ng g^–1 and at 1 µg g^–1 sulfur in iso-octane, the relative standard deviation (n = 5) was ±5.5%.