Todays detection limits are very low. Using various methods such as amperometric detection [1], surface plasmon resonance [2], and laser–induced fluorescence detection [3] it is possible to sense few attomolar (10-18 mol·L-1) concentrations of analytes.
References
- W. Gao, H. Dong, J. Lei, H. Ji, and H. Ju, "Signal amplification of streptavidin–horseradish peroxidase functionalized carbon nanotubes for amperometric detection of attomolar DNA", Chemical Communications, vol. 47, pp. 5220, 2011. http://dx.doi.org/10.1039/C1CC10840A
- J. Ferreira, M.J.L. Santos, M.M. Rahman, A.G. Brolo, R. Gordon, D. Sinton, and E.M. Girotto, "Attomolar Protein Detection Using in-Hole Surface Plasmon Resonance", Journal of the American Chemical Society, vol. 131, pp. 436-437, 2008. http://dx.doi.org/10.1021/ja807704v
- D.B. Craig, J.C.Y. Wong, and N.J. Dovichi, "Detection of Attomolar Concentrations of Alkaline Phosphatase by Capillary Electrophoresis Using Laser-Induced Fluorescence Detection", Analytical Chemistry, vol. 68, pp. 697-700, 1996. http://dx.doi.org/10.1021/ac950650z