Acid-labile sulfide and zero-valence sulfur in plant extracts containing chlorophyll and ionic detergents.

Two methods for analysis of acid-labile sulfide and zero-valence sulfur in plant extracts containing chlorophyll as well as ionic and/or nonionic detergents are presented. Both methods are based on the conversion of sulfide into methylene blue. In the first method an ethyl acetate extraction step is used to remove chlorophyll and its degradation products which otherwise prevent spectrophotometric quantitation of methylene blue. The second assay method employs 35S-labeled plant extracts. This method, which involves thin-layer chromatography and autoradiography, is potentially more sensitive than the spectrophotometric assay in detecting acid-labile sulfide and zero-valence sulfur.