A practical aptaprobe for sulfadimethoxine residue detection in water and fish based on the fluorescence quenching of CdTe QDs by poly(diallyldimethylammonium chloride)

Abstract

A practical aptaprobe for sulfadimethoxine (SDM) detection was established. Based on the electrostatic reaction, a duplex of aptamer and poly(diallyldimethylammonium chloride) (PDDA) was formed, which prevented the quenching effect of PDDA on the fluorescence of CdTe quantum dots (QDs). But the specifically binding of aptamer to SDM might result in free PDDA released and the fluorescence was quenched. Based on the fluorescence aptaprobe, SDM was quantitatively detected by measuring the fluorescence at 530 nm with a linear range of 25–300 ng mL−1, and the limit of detection was 2.24 ng mL−1 based on 3σ/K (n = 9). The aptaprobe was applied to SDM detection with recoveries of 94.2 %–113 % and 104 %–118 % for seawater and fish, respectively. The results showed that the fluorescence aptaprobe was simple and convenient for the rapid detection of SDM residue in water and fish samples.