silica quantum dots nanosensing approach for quantitative detection of pesticides in aqueous solution
Pesticides in agriculture have a large negative impact on human life, so it's crucial to develop a highly sensitive sensor that can detect pesticide residues, this is of paramount importance to maintain safety of food and preserve the ecosystem. These methods utilize fluorescence properties to provide a effective and ideal way to screen these compounds in water and food products, sensors based on quantum dots have been developed to observe pesticides. This technology is derived from the utilization of silica nanoparticles covered with fluorescent particles called "quantum dots", these particles can be triggered by light. When silica quantum dots are exposed to pesticides in water, a reaction occurs between the pesticides and the prepared silica. This reaction has a significant effect on the properties ofpolarized light, the intensity of the light signal from the quantum dots is altered. Silica quantum dots are considered to be the most popular fluorescent components, and they are highly prized due to their exceptional properties and size. A simple process of hydrothermal alkaline treatment was employed to create and alter the surface of silica quantum dots in order to increase their fluorescence emission and thus improve the detection limit ratio. The structural information of the prepared silica was obtained via X-ray diffraction and infrared spectroscopy, then characterized by transmission electron microscopy, using EDX analysis and ultraviolet-visible absorption spectroscopy. The results demonstrated that the prepared silica quantum dots have a consistent size distribution that is (10-18)nm, as well as optical properties, these include a 10 fold increase in fluorescence intensity. (SiQDs) were employed to recognize the pesticide (boracic acid) in water-based solutions. They had a remarkable preference for the pesticide in water-based solutions. The fluorescence intensity was observed to decrease with increasing pesticide concentration, as the regression line shows a linear relationship (R2) within the concentration range of (20-180) ppm, and the detection limit was estimated to be 0.04 μmol. The results indicate that the prepared quantum dots serve as a platform for photoluminescence-based sensing, they have the necessary specificity for environmental applications and can effectively identify the pesticide (boric acid) in water samples.