An Electrochemical Sensor Based on Simple Nano-Modification for Sensitive Detection of Ofloxacin Residue in Animal Derived Food

The residue of ofloxacin in animal derived food would seriously affect human health. This study reports an inexpensive, fast, and simple electrochemical sensor for the sensitive detection of OFL in animal derived food samples. A poly-L-glutamic acid/poly(sulfobutyl-β-cyclodextrin) CdTe quantum dot-modified electrode P(L-Glu)/SEB-β-CD@CdTeQDs/GCE was prepared by an electrochemical polymerization reaction. We investigated the electrochemical behavior of OFL on the sensing electrode by cyclic voltammetry and square wave voltammetry. The results showed that the sensitivity of the sensor was significantly improved under the synergistic effect of L-glutamic acid, sulfobutyl-β-cyclodextrin, and CdTe quantum dots. In addition, the electrochemical reaction process of OFL on the sensing electrode was investigated and the results showed that the transfers of two protons and two electrons were involved in the reaction. Subsequently, the electrochemical sensing method based on P(L-Glu)/SEB-β-CD@CdTeQDs/GCE was developed and validated for the determination of OFL, showing a good linear response in the range of 0.07 ∼ 1 μg·ml⁻¹ with a detection limit of 3.4 ng·ml⁻¹, and the precision and accuracy were high enough. Compared with the conventional HPLC method, the established electrochemical sensing method shows the merits of being eco-friendly, shorter detection time and being much more simple, sensitive, and convenient.