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 from an oil pipeline, wherein the crude oil sample comprises a non-naturally occurring substance;
introducing the crude oil sample to a porous paper substrate without any intervening sample purification steps;
applying solvent and voltage to the crude oil sample on the porous paper 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.
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 analyte 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.
8. The method according to claim 1 , wherein the paper is filter paper.
9. The method according to claim 1 , wherein the paper tapers to a tip.
10. A method for quantifying a corrosion inhibitor in crude oil, the method comprising:
obtaining a crude oil sample comprising a corrosion inhibitor, wherein the crude oil sample is from an oil pipeline;
subjecting the crude oil sample to mass spectrometry analysis without any sample pre-purification steps, wherein the mass spectrometry analysis comprises introducing the crude oil sample to a paper substrate and applying solvent and voltage to the crude oil sample on the substrate to generate ions of the corrosion inhibitor directly and only from the crude oil sample, wherein the applying step is conducted without an external heat source; and
quantifying the corrosion inhibitor in the crude oil sample based on results of the mass spectrometry analysis.
11. The method according to claim 10 , wherein the mass spectrometer is selected from the group consisting of a bench-top mass spectrometer and a miniature mass spectrometer.
12. The method according to claim 10 , wherein the corrosion inhibitor comprises at least one alkyl ammonium salt.
13. The method according to claim 12 , wherein the alkyl ammonium salt is selected from the group consisting of tetradodecylammonium bromide, benzylhexadecyldimethylammonium chloride, and a combination thereof.
14. The method according to claim 10 , wherein the mass spectrometer is coupled with a discontinuous atmospheric pressure interface.
15. The method according to claim 10 , wherein the solvent comprises a mixture of methanol and acetonitrile.
16. The method according to claim 10 , wherein the paper is filter paper.
17. The method according to claim 16 , wherein the paper tapers to a tip.
18. The method according to claim 16 , wherein the paper comprises an internal standard.