Silicon quantum dots-based non-enzymatic fluorescence sensor for ultrasensitive detection of methyl parathion

Abstract

This study developed a novel non-enzymatic fluorescent sensing method based on silicon quantum dots (SiQDs) for the highly sensitive detection of methyl parathion (MP) residues. SiQDs were synthesized via a hydrothermal method using 3-aminopropyltriethoxysilane (APTES) as the silicon precursor and acetaminophen (APAP) as the reducing agent. The method relies on the hydrolysis of MP under alkaline conditions to generate p-nitrophenol (p-NP), which exhibites strong absorption at 400 nm and quenches the fluorescence of SiQDs through the inner filter effect (IFE). This enables the construction of a non-enzymatic fluorescent sensing system for the quantitative detection of MP. Compared with traditional enzyme-based sensors, this method eliminates the need for biological enzymes, offering enhanced stability, lower cost, and simpler operation. Experimental results showed that the sensing system exhibited an excellent linear response within the range of 0.01–9 μg/mL (R² = 0.9961), with a detection limit of 0.003 μg/mL. Furthermore, the SiQDs demonstrated good stability in solid form, which supported their potential for practical applications.