LAUSR

The intensity of electrochemiluminescence (ECL) usually changes rapidly with the progress of the electrochemical process, making it difficult to determine the ECL spectrum with a conventional photomultiplier in a wavelength scan model. Herein, a band-pass filter (BPF)-involved modulating strategy is proposed to upgrade a conventional ECL analyzer to a highly sensitive ECL spectrometer without changing its hardware. The ECL spectrum can be figured out by rapidly and/or continuously modulating a part of the ECL intensity-time curve with a BPF array of different central wavelengths as well as correcting the ECL intensity at different measurement times by a univariate cubic polynomial model. This strategy not only can determine the spectrum of ultra-weak emission with high sensitivity via merely modulating the emission within a short period, including the weak self-ECL from either Ru(bpy)32+ or tripropylamine (TPA), but also can demonstrate the interaction between the co-existing emitters. It is shown that the ECL from both Ru(bpy)32+ and TPA of the Ru(bpy)32+/TPA system can be mutually promoted in electrochemical potential and in a concentration-dependent way. The self-ECL of TPA at the potential of 1.24 V can be enhanced from 4.9- to 51-fold with the Ru(bpy)32+ concentration increasing from 0.01 to 0.8 μM. In the presence of 0.04 μM Ru(bpy)32+, the self-ECL of TPA is enhanced by 94- and 10.2-fold at the potential of 1.01 and 1.76 V, respectively. The portable inexpensive BPF turntable device is also useful in spectrum-resolved multi-analyte determination and ratiometric ECL biosensors.