Melamine assay methods and systems
A method of detecting melamine which includes providing a quantity of SERS-active particles and mixing the SERS-active particles with a solution containing melamine. The method further includes detecting a surface enhanced Raman spectrum of the melamine. The foregoing method may optionally include aggregating the SERS-active particles. Aggregation may occur before or after the SERS-active particles are mixed with a solution containing melamine. The method of detecting melamine may optionally include concentration of the SERS-active particles. The method may further include mixing a chaotropic agent having a higher affinity for a selected binding site than melamine into the solution containing melamine. The method may further include mixing a quantity of a SERS-active standard having a known SERS spectrum with the solution containing melamine and SERS-active particles. Assay apparatus and systems are also disclosed.
1. A method of detecting melamine comprising:
providing a quantity of SERS-active particles;
mixing a solution containing melamine with the SERS-active particles; and
detecting a surface enhanced Raman spectrum of the melamine.
2. The method of detecting melamine of claim 1 further comprising aggregating the SERS-active particles.
3. The method of claim 2 wherein the aggregation step comprises adding an aggregating agent to the mixture of melamine containing solution and SERS-active particles.
4. The method of claim 1 wherein the detecting step is performed without concentration of the SERS-active particles.
5. The method of claim 1 further comprising mixing a chaotropic agent having a higher affinity for a selected binding site than melamine into the solution containing melamine, wherein the chaotropic agent does not exhibit a SERS spectrum.
6. The method of claim 1 further comprising:
providing a quantity of a SERS-active standard having a known SERS spectrum;
mixing the solution containing melamine with the SERS-active particles and the SERS-active standard; and
detecting a surface enhanced Raman spectrum of the SERS-active standard.
7. The method of claim 6 wherein the SERS-active standard is deuterated melamine.
8. A method of detecting melamine comprising:
providing a quantity of SERS-active particles;
providing a quantity of magnetic particles;
associating one or more SERS-active particles with one or more magnetic particles;
mixing a solution containing melamine with the SERS-active particles and magnetic particles;
magnetically concentrating the magnetic particles; and
detecting a surface enhanced Raman spectrum of the melamine.
9. The method of detecting melamine of claim 8 wherein the SERS-active particles are associated with the magnetic particles through electrostatic attraction between the particles.
10. The method of detecting melamine of claim 8 wherein the SERS-active particles are associated with the magnetic particles before the SERS-active particles are associated with the magnetic particles.
11. The method of claim 8 further comprising mixing a chaotropic agent having a higher affinity for a selected binding site than melamine into the solution containing melamine, wherein the chaotropic agent does not exhibit a SERS spectrum.
12. The method of claim 8 further comprising:
providing a quantity of a SERS-active standard having a known SERS spectrum;
mixing the solution containing melamine with the SERS-active particles and the SERS-active standard; and
detecting a surface enhanced Raman spectrum of the SERS-active standard.
13. A method of detecting a molecule of interest comprising:
providing a quantity of SERS-active particles;
providing a quantity of a SERS-active standard having a known SERS spectrum;
mixing a solution containing the molecule of interest with the SERS-active particles and the SERS-active standard;
detecting a surface enhanced Raman spectrum of the molecule of interest; and
detecting a surface enhanced Raman spectrum of the SERS-active standard.
14. The method of claim 13 further comprising concentrating the SERS-active particles and the SERS-active standard.
15. The method of claim 14 further comprising:
providing a quantity of magnetic particles;
associating one or more of the SERS-active particles and a select quantity of the SERS-active standard with one or more magnetic particles; and
magnetically concentrating the magnetic particles.
16. The method of claim 13 wherein the SERS-active standard is an analog of the molecule of interest.
17. The method of claim 16 wherein the SERS-active standard is deuterated melamine and the molecule of interest is melamine.
18. An assay system comprising:
a quantity of SERS-active particles;
a quantity of a SERS-active standard;
a container for mixing a solution of a molecule of interest with the SERS-active particles and the SERS-active standard; and
a SERS reader configured to obtain a SERS spectrum of the molecule of interest and a SERS spectrum of the SERS-active standard.
19. The assay system of claim 18 further comprising: a quantity of magnetic particles; and a magnetic concentration apparatus.
20. The assay of system of claim 18 further comprising an aggregating agent.
21. The assay of system of claim 18 further comprising a chaotropic agent that does not exhibit a SERS spectrum.
22. The assay of system of claim 18 wherein the molecule of interest is melamine.