Resonance Scattering Spectral Determination of Trace Penicillin G Using Immunonanogold-HauCI4-NH2OH Catalytic Reaction

摘要

Both nanogold and immunonanogold exhibit catalytic effect on the slow reaction of HAuCl4-NH2OH to form gold particles which displayed a resonance scattering (RS) peak at 580 nm. Using hapten penicillin G (PG) as a model, the nanogold in size of 9 nm was used to label rabbit anti-penicillin G antisera (RAPG) to obtain an immu- nonanogold probe (AuRAPG) for PG. The PG was combined with AuRAPG to form the immunocomplex and big- ger nanogold clusters. After centrifugation, the excess AuRAPG in the supematant exhibited catalytic effect on the reaction of HAuCl4-NH2OH, and the RS intensity at 580 nm (I580 nm) was enhanced greatly. With the addition of PG, the I580 nm decreased accordingly. Under the optimal conditions, the decreased intensity ΔI580 nm was proportional to the PG concentration in the range of 0.15-225 ng/mL, with a detection limit of 0.05 ng/mL for PG.