Metronidazole Determination in Raw Milk with a Graphene Aerogel-Based Electrochemiluminescent Sensor and Its Effect on Cell Apoptosis

Herein an electrochemiluminescence (ECL) sensor based on graphene aerogel (GA) for detecting metronidazole (MTZ) was proposed. The ECL behavior of the Ru(bpy)32+-doped silica nanoparticles (SiO2@Ru(bpy)32+ NPs) was investigated with MTZ as the coreactant. Quantitative detection of MTZ was realized as MTZ could effectively enhance the ECL signal of the SiO2@Ru(bpy)32+ NPs. A wide linear range of 2.5 to 250 μM (r = 0.9937) was obtained under optimized conditions, and a detection limit (S/N = 3) was achieved as low as 0.5 μM. Finally, the analytical application of the proposed sensor was evaluated by detecting a drug sample and MTZ residues in raw milk. Additionally, MTZ was an apoptosis inducer toward MCF-7 cells, and our method could measure the accurate concentration of MTZ which can cause serious apoptosis in cellular experiments. Thus, with good stability, acceptable precision, and reproducibility, the proposed sensor supports promising practicability in clinical analysis.