“…Elemental analysis of sulfur in the nanogram region is accomplished by hydrogenation to H2S and by fluorometric analysis of H2S by quenching the intensity of fluorescein-Hg-acetate (352). Several articles describe the determination of H2S in the air (377) and in water (1045, IO46). Mercury (II)-2,2'-pyridylbenzimidazol is also used for the determination of sulfides down to 0.3 ng of S2-/ml of test solution.…”