Silicon quantum dot involved luminol chemiluminescence and its sensitive detection of dopamine

Abstract

Water dispersible silicon quantum dots (SiQDs) were synthesized by in situ growth under microwave irradiation. The prepared SiQDs were characterized by transmission electron microscopy, FT-IR, and fluorescence spectroscopy. Under neutral conditions, a weak chemiluminescence (CL) signal was obtained in luminol/K₂S₂O₈ and SiQDs/K₂S₂O₈ mixed solutions, while a strong CL signal was obtained in the presence of luminol, K₂S₂O₈, and SiQDs. The CL spectra revealed that two luminophores were involved in the present CL system, and the possible CL mechanism was proposed. Dopamine (DA) exhibited a significantly inhibiting effect on the CL signal of the luminol/K₂S₂O₈/SiQD system, and the inhibited CL intensities were proportional to the logarithm of DA concentration in the range of 1.0 × 10⁻⁹ to 5.0 × 10⁻⁷ mol L⁻¹ with a detection limit of 8.6 × 10⁻¹⁰ mol L⁻¹. The proposed CL system can be successfully applied in the sensitive detection of trace levels of DA in real samples.