A method to determine the distribution of non-reactive sulfur compounds and reactive sulfur compounds in petroleum samples by separating non-reactive sulfur compounds from reactive sulfur compounds in a petroleum composition includes the step of contacting the petroleum composition with a Ag-containing cation exchange media. The petroleum composition and the Ag-containing cation exchange media are contacted with a non-reactive sulfur compound solvent capable of eluting the non-reactive sulfur compounds in the presence of the Ag-containing cation exchange media and incapable of eluting the reactive sulfur compounds in the presence of the Ag-containing cation exchange media at the conditions of the exchange. The non-reactive sulfur compounds are eluted from the media with the non-reactive sulfur compound solvent to provide a first fraction. The amount of non-reactive sulfur compounds in the first fraction is then determined.