Fluorescence sensor based on rhodamine B and gold-clad silver nanoparticles and application of fluorescence sensor to detection of organophosphorus pesticide

Abstract

According to the invention, a simple and efficient open-type fluorescent nano-sensor is developed by combining gold-clad silver nanoparticles with core-shell structures and rhodamine B, and is used for sensitive detection of organic phosphorus pesticide residues. Rhodamine B is used as a fluorescence source to emit orange-yellow light, and silver-coated gold nanoparticles are used as a quenching agent to quench orange-yellow fluorescence. Due to the addition of the organophosphorus pesticide, the aggregation of the gold-coated silver nanoparticles and the recovery of orange-yellow emission are caused, so that the organophosphorus pesticide is detected on the basis of a fluorescence opening principle. The fluorescent nano sensor has a good detection effect on organophosphorus pesticides, and the detection limit in a fluorescent mode is 7.89 nM. Besides, the organophosphorus pesticide residues in an actual sample are quantitatively detected by utilizing a smart phone sensing platform and adopting an RGB (Red, Green and Blue) analysis method. The designed nano-sensor responds to a detection signal by virtue of fluorescence opening, shows obvious change from dark fluorescence intensity to bright orange-yellow fluorescence, effectively improves the visual effect of the sensor, realizes quantitative detection by combining with a smart phone, and expands the application in the aspects of on-site in-situ organophosphorus pesticide residue detection and food safety.

Description

technical field [0001] The invention relates to a fluorescent nanosensor based on rhodamine B and gold-coated silver nanoparticle composite materials and a highly sensitive fluorescence visualization quantitative detection method for organophosphorus pesticide residues in actual water samples and on the skins of fruits and vegetables. Background technique [0002] Organophosphorus pesticides are currently the most widely used pesticides in my country, and most of them are explicitly prohibited from being used on vegetables and fruits. Since this type of pesticide will combine with acetylcholinease after entering the organism, the acetylcholine in the nerve conduction of the organism cannot be hydrolyzed and excessively accumulates, resulting in nervous excitement, followed by poisoning symptoms, and severe cases directly die. Therefore, we must pay attention to the importance of pesticide residue detection. Fluorescence detection method has fast response, simplicity and hig...

AI Technical Summary

Problems solved by technology

However, most of the fluorescent sensors currently used for the detection of organophosphorus pesticides are based on enzyme inhibition, which has certain shortcomings in terms of detection conditions, time, and cost; some special actual detection environments interfere with the detection results, resulting in False positive or false negative test results

Moreover, most quantitative fluorescence detection methods require professional technicians and expensive, complex and heavy instruments, making it difficult to implement on-site detection

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