Gold nanoparticle-enhanced capillary electrophoresis-chemiluminescence assay of trace uric acid.

A sensitive method based on gold nanoparticle-enhanced CE-chemiluminescence (CL) detection was developed for quantifying uric acid (UA) in serum. In this work, gold nanoparticles were added into the running buffer of CE to catalyze the post-column CL reaction between luminol and hydrogen peroxide, achieving highly efficient CL emission. Negative peaks were produced due to the inhibitory effects on CL emission from UA eluted from the electrophoretic capillary. The decrease in CL intensity was proportional to the concentration of UA in the range of 2.5x10(-7)-1.0x10(-5) M. Detection limit was 4.6x10(-8) M UA. Ten human serum samples were analyzed by the presented method. Serum level of UA was found to be in the range from 204 to 324 microM for healthy subjects (n=5), and from 464 to 497 microM for diabetic patients (n=5). The two groups were significantly different (p<0.05). The results suggested a potential application of the proposed assay in rapid primary diagnosis of diseases such as diabetes.