Well-Established Long-Lasting Chemiluminescence Platform Based on Deep Eutectic Solvents

Long-lasting chemiluminescence (CL) has garnered substantial attention due to its superior controllability and minimal instrumentation requirements compared with conventional flash-type CL systems. However, most existing long-lasting CL systems still rely on the fabrication of complex microreactors to retard mass diffusion. In this study, we propose a facile “all-in-one” mixing platform for triggering long-lasting CL emission using deep eutectic solvents (DESs) as microreactors. Systematic screening identified choline chloride–urea (ChCl–urea) as the optimal DES, owing to its appropriate viscosity and favorable melting temperature. The CL coreactant accelerator of Co2+ was preincorporated into the DES via coordination bonds, where it exhibited high catalytic activity and excellent dispersibility (denoted as Co@DES). The DES functioned as a controlled-release reservoir, gradually delivering Co2+ to the overlying CL aqueous phase while simultaneously enriching luminol at the aqueous–Co@DES interface. The retarded diffusion of Co2+ facilitated the decomposition of H2O2 to continuously generate reactive oxygen species, which in turn reacted with luminol to produce sustained CL emission. Under optimized conditions, the developed system maintained a stable CL for up to 72 h, whereas the CL in the single aqueous phase decayed within 5 min. DES-modulated slow diffusion enabled a generalizable strategy for long-lasting CL and can be readily extended to diverse reactant combinations, including various coreactant accelerators and CL emitters. With regard to intensity, duration time, and catalytic characteristics, sensitive detection of H2O2 and alkaline phosphatase (ALP) was constructed based on the integrated intensity, indicating its great potential in immunoassays.