Fig. 3.
Immunoassay based on gold nanoparticle–ECL detection. Different concentrations of SEB were detected by the CCD camera: (1A), 50 ng/mL; (1B), 10 ng/mL; (1C), 5 ng/mL; (2A), 1 ng/mL; (2B), 0.5 ng/mL; (2C), 0.1 ng/mL; (3A), 0.05 ng/mL; (3B), 0.01 ng/mL; and (3C), 0 ng/mL. Exposure time is 15 min.