Quantum dot-enhanced chemiluminescence detection for simultaneous determination of dopamine and epinephrine by capillary electrophoresis

A sensitive method based on quantum dot (QD)-enhanced capillary electrophoresis–chemiluminescence (CE–CL) detection was developed for simultaneous determination of dopamine (DA) and epinephrine (E). In this work, CdTe QD was added into the running buffer of CE to catalyze the post-column CL reaction between luminol and hydrogen peroxide, achieving higher CL emission. Negative peaks were produced due to the inhibitory effects on CL emission from DA and E eluted from the electrophoretic capillary. The decrease in CL intensity was proportional to the concentration of DA and E in the range of 8.0 × 10−8–5.0 × 10−6 M and 4.0 × 10−8–5.0 × 10−6 M, respectively. Detection limits for DA and E were 2.3 × 10−8 M and 9.3 × 10−9 M, respectively. Using this method, the levels of DA and E in human urine from healthy donors were determined.