Methods of analyzing crude oil
The invention generally relates to methods of analyzing crude oil. In certain embodiments, methods of the invention involve obtaining a crude oil sample, and subjecting the crude oil sample to mass spectrometry analysis. In certain embodiments, the method is performed without any sample pre-purification steps.
1. A method for analyzing a crude oil sample, the method comprising:
obtaining a crude oil sample comprising a non-naturally occurring substance within the crude oil sample;
introducing the crude oil sample to a porous paper substrate;
applying solvent and voltage to the crude oil sample on the substrate to generate ions of the non-naturally occurring substance directly and only from the crude oil sample, wherein the applying step is conducted without an external heat source; and
analyzing the ions using a mass spectrometer, wherein the method is performed without pre-purification of the crude oil sample.
2. The method according to claim 1 , wherein the mass spectrometer is selected from the group consisting of a bench-top mass spectrometer and a miniature mass spectrometer.
3. The method according to claim 1 , wherein the non-naturally occurring substance in the crude oil is a corrosion inhibitor.
4. The method according to claim 3 , wherein the corrosion inhibitor comprises at least one alkyl ammonium salt.
5. The method according to claim 4 , wherein the alkyl ammonium salt is selected from the group consisting of tetradodecylammonium bromide, benzylhexadecyldimethylammonium chloride, and a combination thereof.
6. The method according to claim 1 , wherein the mass spectrometer is coupled with a discontinuous atmospheric pressure interface.
7. The method according to claim 1 , wherein the solvent comprises a mixture of methanol and acetonitrile.