硫磺素T非标记荧光核酸适配体传感器快速检测二氯喹啉酸除草剂OA

A label-free fluorescent aptasensor based on thioflavin T(ThT)fluorescent probe was developed for rapid detection of quinclorac(QNC).In this sensor system,ThT specifically bound to the QNC aptamer Qapt-48nt with G-quadruplex structure,resulting in a significantly enhanced fluorescence signal.Upon addition of QNC,it competitively bound to Qapt-48nt,forming a QNC-Qapt complex and releasing free ThT,leading to a decrease in the fluorescence intensity of the system.Under optimal conditions,the linear detection range of this sensor for QNC was 0.012–4.84 μg/mL,the limit of detection(S/N=3)was 3.3 ng/mL,and the limit of quantification(S/N=10)was 9.8 ng/mL.This method was successfully applied to detection of QNC in river water,soil and rice samples,with recoveries ranging from 83.3%to 108.3% and relative standard deviations of 3.9% to 8.8%,and the results were comparable to those of HPLC-MS/MS method.The established aptasensor could complete the detection of QNC within 2 min,featuring simplicity,rapidity,and high specificity,and providing a novel method for rapid detection of QNC residues in environmental and food samples.