Electrochemiluminescence of Luminol-Tripropylamine System

Hydrogen peroxide is a dominating coreactant of most luminol electrochemiluminescence (ECL) studies though it is unstable and sensitive to many metal ions. Tripropylamine is an eminent coreactant of tris(2,2'-bipyridine)ruthenium ECL. In comparison with H2O2, tripropylamine is much more stable. In this study, tripropylamine has been exploited as a new coreactant of luminol ECL for the first time. The emission spectrum reveals that the ECL peak was aroused by excited 3-aminophthalate. Under optimized conditions, a biphasic linear relationship is obtained between the ECL intensities and luminol concentrations in the presence of 10 mM tripropylamine over the range of 1.0 × 10−11 −1.0 × 10−7 M and 1.0 × 10−7 −1.0 × 10−4 M with a detection limit of 6.9 × 10−12 M. The detection of tripropylamine showed a linear relationship between ECL intensities and tripropylamine concentrations in the range of 1.0 × 10−6 to 1.0 × 10−2 M with a detection limit of 7.7 × 10−7 M. Compared to luminol-H2O2 ECL, luminol-tripropylamine ECL system displays not only high stability but also high sensitivity. Hence, it shows great potential in many fields including immunoassay or non-immunoassay diagnostic, clinical, pharmaceutical, environmental and food analysis in the future.