| In this paper,hydrogen peroxide,bisphenol A and tetracycline were detected by using electrochemiluminescence technology as a detection tool,introducing different nanomaterials and dual-signals ratio strategy,or combinating with magnetic field enhanced solid-phase microextraction.Quantum dots have good catalytic properties and unique optical and electrochemical properties,and have been extensively applied in electrochemiluminescence analysis;Carbon nanodots are a kind of spherical nano-materials,which have the unique advantages of good water solubility,biocompatibility,chemical inertness and non-toxicity,which have an important impact on analytical testing.In addition,for the samples with low content and complex matrix,the adoption of high-efficiency pretreatment technology is an effective measure to improve the reliability of the detection results of the target.Magnetic enhanced solid phase microextraction can effectively achieve extraction of the targets due to the magnetic force is not easily affected by chemical environmental factors,and the separation of targets does not require additional devices and instruments,Therefore,the sample pretreatment technique using magnetic field enhanced microextraction can effectively improve the anti-interference ability of the analytical method.In this paper,quantum dots are prepared as illuminant and carbon nanodots as coreactant.A novel double-signals electrochemiluminescence ratio strategy was developed,or electrochemiluminescence combined with magnetic field enhanced microextraction technology was used to improve the sensitivity and selectivity of detection.The details as follows:1.Dual-signal electrochemiluminescence ratiometry based the synergic effect between luminol and CdSe quantum dots for direct detection of hydrogen peroxideA dual signal ECL ratiometric strategy for the detection of hydrogen peroxide was designed based on the synergic effect of the catalysis effect and ECL resonance energy transfer.It was found that CdSe quantum dots?CdSe QDs?can catalyze the oxidation of luminol to promote the signal intensity of luminol at 0.45 V.At the same time,it was observed that a stronger cathodic ECL peak at?0.75 V from CdSe QDs,which could be attributed to the resonance energy transfer between luminol as a donor and CdSe QDs as an acceptor.Moreover both signals from two different potentials increased with the increase hydrogen peroxide concentration.On the basis of the above results,an enzyme-free ECL sensor was fabricated by immobilization of coating CdSe QDs on Au-graphite oxide?GO-AuNPs?composites modified glassy carbon electrode?GCE?,and luminol solution as probe solution,which was used to detect rapidly and sensitively hydrogen peroxide.The ratio of the double intensity has a good linear relationship with the concentration of hydrogen peroxide in the range from 0.5 to 500?mol/L.The linear correlation coefficient and detection limit are 0.9972 and 0.5?mol/L,respectively.The sensor exhibited good reproducibility and sensitivity,suggesting that the simple method will be promising in the detection of active oxygen in environmental samples.2.One-Step constructed electrochemiluminescence sensor coupled with magnetic enhanced solid phase microextraction to sensitively detect bisphenol-AIn this study,an electrochemiluminescence quenching method combined with magnetic field enhanced microextraction was proposed for the extraction and detection of bisphenol A.The GO-Fe3O4 composite was prepared as a magnetic extractant to extract bisphenol A.The results showed that the magnetic field provided by the external magnet can not only achieve rapid separation,but also improve extraction efficiency.The GO-AuNPs complex?GO-AuNPs?combined the advantages of large specific surface area of graphene oxide and good conductivity of Au nanoparticles.Therefore,the GO-AuNPs complex was coated on the surface of the glassy carbon electrode,and an electrochemiluminescence sensor was constructed.During the detection,bisphenol A quenched the enhanced luminol electrochemiluminescence intensity of GO-AuNPs.Under the condition of experimental optimization,there was a good linear relationship between the quenching value of electrochemiluminescence intensity and the negative logarithmic value of bisphenol A concentration within 1.0×10-8 to 1.0×10-4 mol/L,and the linear correlation coefficient and detection limit were 0.9920 and 4.2×10-9 mol/L,respectively.Since GO-AuNPs can enhance the luminol electrochemiluminescence intensity and the enrichment of the target before detection,the coupling method exhibits high sensitivity in the detection of bisphenol A in actual samples.3.Dual-signal electrochemiluminescence ratiometry based on carbon dots as coreactant combined with magnetic enhanced solid phase microextraction to detect tetracyclineThis study designed and developed a novel dual-signal electrochemiluminescence ratio method combined with magnetic field enhanced microextraction for the extraction and detection of tetracycline.Owing to the good surface affinity of Zn2+toward tetracycline,Fe3O4@SiO2@ZnO magenetic nanocomposites were fabricated to extract TC based on the use of external magnetic field in the process of extraction,the extraction efficiency was about 87.6%.During the detection procedure,when the potential was scanned between?3.5 and 2 V,Ru?bpy?32+was acted as a single luminophore that can generate double ECL signals based on the introduction of carbon nanodots as coreactant.Meanwhile,it was found that dual-signals intensity both decreased with the increase of TC concentration.Under the optimal conditions,the ratio of the double signal intensity has a good linear relationship with the negative value of the logarithm of tetracycline concentration in the range from 1.0×10-9 to 1.0×10-44 mol/L,and the detection limit was 4.7×10-10 mol/L,linear correlation coefficient was 0.9940.The designed approach was successfully applied to detect TC in real samoles,which exhibited good sensitivity,selectivity and accuracy based on the double ECL signal system and preconcentration of analytes. |
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