Stable liquid membranes for liquid phase microextraction

1. A device for performing liquid phase microextraction of at least one analyte from an aqueous sample comprising a liquid membrane supported on a porous polymeric substrate, wherein said liquid membrane has one side that can be placed in fluid communication with the aqueous sample containing the at least one analyte and a second side that can be placed in fluid communication with an acceptor solution, and wherein said liquid membrane comprises a fatty acid ester, wherein said fatty acid ester comprises an acyl chain comprising from 12 to 30 carbon atoms.

2. The device of claim 1 , wherein said porous polymeric substrate is a hollow fiber.

3. The device of claim 1 , wherein said fatty acid ester comprises an ester portion comprising from 1 to 12 carbon atoms.

4. The device of claim 1 , wherein said liquid membrane further comprises a vegetable oil.

5. The device of claim 1 , wherein the liquid membrane further comprises a carrier.

6. The device of claim 5 , wherein the carrier is an organic ion, an ionophore or a pore forming agent.

7. The device of claim 6 , wherein the carrier is an organic ion.

8. The device of claim 7 , wherein the organic ion is trioctyiphosphine oxide (TOPO), diethyihexyl phosphoric acid, triethylhexyl phosphoric acid, dodecylbenzene sulphonic acid, aliquat 336 (trioctylmethylammonium chloride), amberlite LA, tri-n-octyl amine, tetraphenylphosphonium, tetraphenylarsonium, trinitrophenol, or tetraphenylboron.

9. The device of claim 1 , wherein said polymeric substrate comprises a polyolefin, acrylic copolymer, polyamide, polyester, polyurethane, polycarbonate, polystyrene, fluorinated polymer, polyvinyl chloride, polyacrylonitrile, copolymers thereof, or mixtures thereof.

10. The device of claim 9 , wherein the polymeric substrate comprises a polyolefin.

11. The device of claim 10 , wherein the polyolefin is polyethylene, polypropylene, polytetrafluoroethylene, poly(tetrafluoroethylene-co-ethyl-ene), or polyethylene-polyvinyl chloride copolymer, copolymers thereof, or mixtures thereof.

12. The device of claim 1 , wherein said liquid membrane is stable for at least 30 days, 60 days or 90 days.

13. The device of claim 2 , wherein said hollow fiber is able to extract at least one analyte after being stored for at least 30 days, 60 days or 90 days.

14. The device of claim 1 , wherein in operation, the acceptor solution is placed inside the hollow fiber and the hollow fiber is placed in the sample solution.

15. The device of claim 1 , wherein the acceptor solution can be sampled by an autosampler.

16. A device for carrying out liquid phase microextraction of at least one analyte from an aqueous sample, said device comprising a hollow fiber comprised of a porous polymeric substrate and a liquid membrane supported thereon, wherein said liquid membrane comprises a fatty acid ester, wherein said fatty acid ester comprises an acyl chain comprising from 12 to 30 carbon atoms.

17. The device of claim 16 , wherein said polymeric substrate comprises a polyolefin, acrylic copolymer, polyamide, polyester, polyurethane, polycarbonate, polystyrene, fluorinated polymer, polyvinyl chloride, polyacrylonitrile, copolymers thereof, or mixtures thereof.

18. The device of claim 17 , wherein the polymeric substrate comprises a polyolefin.

19. The device of claim 16 , wherein said liquid membrane is stable for at least 30 days, 60 days or 90 days.

20. The device of claim 1 , wherein the liquid membrane further comprises a nitroarylalkylether.

21. A device for performing liquid phase microextraction of at least one analyte from an aqueous sample comprising a liquid membrane supported on a porous polymeric substrate, wherein said liquid membrane has one side that can be placed in fluid communication with the aqueous sample containing the at least one analyte and a second side that can be placed in fluid communication with an acceptor solution, and wherein said liquid membrane comprises a fatty acid ester, or a vegetable oil, a silicone oil, or mixtures thereof, wherein the liquid membrane further comprises a preservative.

22. The device of claim 2 , wherein the liquid membrane supported on a hollow fiber is stored in a closed container prior to use.

23. The device of claim 16 , wherein the hollow fiber comprised of a porous polymeric substrate and a liquid membrane supported thereon is stored in a closed container prior to use.

24. The device of claim 16 , wherein the liquid membrane further comprises a nitroarylalkylether.

25. A device for carrying out liquid phase microextraction of at least one analyte from an aqueous sample, said device comprising a hollow fiber comprised of a porous polymeric substrate and a liquid membrane supported thereon, wherein said liquid membrane comprises a fatty acid ester, or a vegetable oil, a silicone oil, or mixtures thereof, wherein the liquid membrane further comprises a preservative.

26. A device for carrying out liquid phase microextraction of at least one analyte from an aqueous sample, said device comprising a hollow fiber comprised of a porous polymeric substrate and a liquid membrane supported thereon, wherein said Liquid membrane comprises a mixture comprising a silicone oil and one or more of a fatty acid ester, a vegetable oil, or a nitroarylalkylether.

27. The device of claim 26 , wherein the liquid membrane further comprises a carrier.

28. The device of claim 4 , wherein the vegetable oil is soya oil, olive oil or tea tree oil.

29. The device of claim 16 , wherein said liquid membrane further comprises a vegetable oil.

30. The device of claim 29 , wherein the vegetable oil is soya oil, olive oil or tea tree oil.