Abstract In this paper, CdS quantum dots (QDs) were synthesized. Positively charged poly(diallyldimethylammonium chloride) (PDDA) and negatively charged CdS quantum dots were sequentially adsorbed on the surface of graphene oxide (GO). The nano-luminescent materials GO-QDs were prepared and characterized by UV–Vis absorption spectroscopy, fluorescence spectroscopy and transmission electron microscopy. The GO-QDs were then modified on the surface of glassy carbon electrode (GCE). Chloramphenicol aptamer (apt) of 5′-end modified biotin hybridized with the aptamer complementary strand (cDNA) of 5′-end modified amino group into double-stranded DNA (dsDNA). The double-stranded DNA was bonded onto the surface of GO-QDs modified electrode. When the electrode was incubated with streptavidin - labeled horseradish peroxidase (SA-HRP), the biotin modified at the end of the chloramphenicol aptamer can specifically bind directly to the streptavidin labeled HRP. Therefore, HRP was bonded to the surface of the electrode. Hydrogen peroxide was used as the co-reactant of the QDs. HRP can thereby consume hydrogen peroxide and can weaken the electrochemiluminescence intensity. Chloramphenicol in solution can specifically bind to the aptamer to form a composite and to unwind the dsDNA. Then the composite was detached from the surface of the electrode. HRP also left the electrode surface along with the aptamer, so that the electrochemiluminescence signal was significantly enhanced. The electrochemiluminescence intensity of the sensor showed a linear correlation with the logarithm of chloramphenicol concentration. The linear range was 1.0 × 10−12–1.0 × 10−7 M, the detection limit is 0.5 pM. The reproducibility, stability and specificity of the sensor were also studied. The sensor was used for the determination of chloramphenicol in samples and satisfactory results were obtained.

中文翻译：

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基于GO-QDs纳米复合材料和酶联适体的氯霉素电化学发光适体传感器

摘要 本文合成了CdS 量子点(QDs)。带正电荷的聚（二烯丙基二甲基氯化铵）（PDDA）和带负电荷的 CdS 量子点依次吸附在氧化石墨烯（GO）的表面。制备了纳米发光材料GO-QD，并通过紫外-可见吸收光谱、荧光光谱和透射电子显微镜对其进行了表征。然后在玻璃碳电极（GCE）的表面上修饰 GO-QD。5'-末端修饰的生物素的氯霉素适体（apt）与5'-末端修饰的氨基的适体互补链（cDNA）杂交成双链DNA（dsDNA）。双链 DNA 结合到 GO-QDs 修饰电极的表面。当电极与链霉亲和素标记的辣根过氧化物酶 (SA-HRP) 一起孵育时，氯霉素适体末端修饰的生物素可以直接与链霉亲和素标记的HRP特异性结合。因此，HRP 结合到电极表面。过氧化氢用作 QD 的共反应物。HRP因此可以消耗过氧化氢并且可以减弱电化学发光强度。溶液中的氯霉素可以与适体特异性结合以形成复合物并解开 dsDNA。然后将复合材料从电极表面分离。HRP 也与适体一起离开电极表面，使电化学发光信号显着增强。传感器的电化学发光强度与氯霉素浓度的对数呈线性相关。线性范围为 1.0 × 10−12–1.0 × 10−7 M，检出限为 0。下午 5 点。还研究了传感器的再现性、稳定性和特异性。将该传感器用于样品中氯霉素的测定，结果令人满意。