Compositions and methods for detecting lead ions

1. A composition comprising an aniline copolymer and a vinyl polymer, wherein the aniline copolymer comprises at least one first monomer unit and at least one second monomer unit, wherein the first monomer unit is optionally substituted 2-hydroxy-5-sulfonic aniline, and wherein the second monomer unit is aniline.

2. The composition of claim 1 , wherein the first monomer unit is represented by Formula I:

wherein R 1 is hydrogen or an electron-donating group, and R 2 is hydrogen or an electron-donating group.

3. The composition of claim 2 , wherein R 1 is hydrogen and R 2 is hydrogen.

4. The composition of claim 2 , wherein the electron-donating group is C 1-6 alkyl.

5. The composition of claim 1 , wherein the aniline copolymer comprises at least about 5% of the first monomer unit by mole.

6. The composition of claim 1 , wherein the aniline copolymer has a molar ratio of the first monomer unit to the second monomer unit from about 1:99 to about 50:50.

7. The composition of claim 1 , wherein the aniline copolymer is present as nanoparticles.

8. The composition of claim 1 , wherein the vinyl polymer is selected from the group consisting of polyvinyl fluoride (PVF); polyvinyl acetate (PVAc); polyvinyl alcohol (PVA); polyvinylidene fluoride (PVDF); polyvinylidene chloride (PVDC); polytetrafluoroethylene (PTFE); copolymers of vinyl chloride comprising no more than 50% by weight of vinyl acetate or vinyl alcohol; and a combination thereof.

9. The composition of claim 1 , wherein the vinyl polymer is a copolymer of vinyl chloride, vinyl acetate and vinyl alcohol.

10. The composition of claim 1 , wherein the vinyl polymer is a copolymer of vinyl chloride and vinyl acetate.

11. The composition of claim 10 , wherein the vinyl polymer comprises about 3% to about 50% vinyl acetate by weight.

12. The composition of claim 10 , wherein the vinyl polymer comprises about 50% to about 90% vinyl chloride by weight.

13. The composition of claim 9 , wherein the vinyl polymer comprises no more than about 30% vinyl alcohol by weight.

14. The composition of claim 1 , wherein the composition is substantially plasticizer-free.

15. A polymeric membrane for ion sensitive measurement comprising a vinyl polymer and one or more ionophores selective for lead ions wherein the one or more ionophores comprise an aniline copolymer, wherein the aniline copolymer comprises at least one optionally substituted 2-hydroxy-5-sulfonic aniline as a first monomer unit and at least one aniline as a second monomer unit.

16. The polymeric membrane of claim 15 , wherein the first monomer unit is represented by Formula I:

wherein R 1 is hydrogen or an electron-donating group, and R 2 is hydrogen or an electron-donating group.

17. The polymeric membrane of claim 16 , wherein R 1 is hydrogen and R 2 is hydrogen.

18. The polymeric membrane of claim 16 , wherein the electron-donating group is C 1-6 alkyl.

19. The polymeric membrane of claim 15 , wherein the polymeric membrane has about 0.5% to about 10% the one or more ionophores by weight.

20. The polymeric membrane of claim 15 , wherein the polymeric membrane comprises one or more ion exchangers.

21. The polymeric membrane of claim 20 , wherein the polymeric membrane has about 0.5% to about 10% the one or more ion exchangers by weight.

22. The polymeric membrane of claim 20 , wherein the one or more exchangers are selected from the group consisting of sodium tetraphenylborate (NaTPB), potassium tetraphenylborate (KTPB), potassium tetrakis(4-chlorophenyl) borate (KTClPB), potassium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (KTFPB), sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (NaTFPB), and combinations thereof.

23. The polymeric membrane of claim 15 , wherein the polymeric membrane has an average thickness of about 40 μm to about 200 μm.

24. The polymeric membrane of claim 15 , wherein the polymeric membrane has an operating lifetime of more than about 6 months.

25. A sensor for measuring lead ions, the sensor comprising: a lead ion-selective electrode, wherein the lead ion-selective electrode comprises a vinyl polymer and an aniline copolymer, wherein the aniline copolymer comprises at least one optionally substituted 2-hydroxy-5-sulfonic aniline as a first monomer unit and at least one aniline as a second monomer unit.

26. The sensor of claim 25 , wherein the sensor further comprises a reference electrode.

27. A method for detecting lead ions in a sample, the method comprising:

providing a sample suspected of containing one or more lead ions;

contacting the sample with a sensor, wherein the sensor comprises a reference electrode and a lead ion-selective electrode, wherein the lead ion-selective electrode comprises a vinyl polymer and one or more ionophores selective for lead ions wherein the one or more ionophores comprise an aniline copolymer, wherein the aniline copolymer comprises at least one optionally substituted 2-hydroxy-5-sulfonic aniline as a first monomer unit and at least one aniline as a second monomer unit; and

measuring an electromotive force (EMF) between the reference electrode and the lead ion-selective electrode.

28. The method of claim 27 , wherein the sensor is potentiometric and functions substantially logarithmic.

29. The method of claim 27 , wherein the measured EMF is greater in the presence of lead ions than in the absence of lead ions.

30. The method of claim 27 , wherein the concentration of the lead ions in the sample is about 10 −3 M to about 10 −11 M.

31. The method of claim 27 , wherein the sample is contacted with the sensor for no more than about 10 minutes.