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 x 10 (11) -1.0 x 10 M-7 and 1.0 x 10 (7) -1.0 x 10 (4) M with a detection limit of 6.9 x 10 (12) M. The detection of tripropylamine showed a linear relationship between ECL intensities and tripropylamine concentrations in the range of 1.0 x 10 (6) to 1.0 x 10 (2) M with a detection limit of 7.7 x 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. (C) 2016 Elsevier Ltd. All rights reserved.