| Carbon dots is a new fluorescent nanoparticles with a small particle size, strong penetrability, high optical and chemical stability. The emission spectra of carbon dots can be regulated and easy to surface functionalization. The integral element of carbon dots is similar to that of organism. The primary integral element of carbon dots is C,which have more incomparable advantage than traditional quantum dots in biocompatibility. However, carbon dot surface contains many strong electron withdrawing groups, these groups can reduce the fluorescence properties of carbon dots, therefore, people often reduce the strong electron-withdrawing group of carbon surface using a polymer modified in order to achieve improvement, in order to improve the fluorescent performance, increase the quantum yield, enhanced biocompatibility of carbon dots. This paper uses simple, environmentally friendly hydrothermal synthesis method, one step to synthesis unmodified carbon dots and polyamide dendrimers- amine(PAMAM) modified carbon dots. We compare the two carbon dots analysis, observe morphology, optical properties, sensor performance by many techniques. The major work and results are as followed:In the first part of this paper, the sythesis and electrochemical performance study of CDs. Stable, watersoluble and well-dispersed CDs was successfully sythesized with hydrothermal. We charactered the perpared CDs by TEM, FTIR, XPS, UV-vis and FL spectroscopy. The CDs was modified onto the GCE by directly dispensing.The EC performance of film electrode was charactered by CV techniques. The EC performance of CDs/GCE and the optimized conditions were investigated in the p H =7.4 PBS. The results indicting that the proposed EC sensor possess good stability,high response sensitivity, wide linear rang from 1.5×10-7 M to 1.5×10-4 M and low detection limit 2.6×10-8 M to dopamine. This film electrode sensor was used to detect actual sample and the satisfied result was obtained.In the second part of paper, the controllable synthesis and the performance study of PAMAM-CDs. Based on the synthesis of CDs, well-controlled PAMAM-CDs wasfurther obtained. We charactered the prepared PAMAM-CDs by TEM, FL spectroscopy and electrochemical techniques and investigated morphology, optical performance and electrochemical performance. The results indicted that the synthesized PAMAM-CDs under the optimizing conditions was more stable,dispersed and its particle size was smaller than CDs. The obtained PAMAM-CDs own more symmetrical peak pattern, stronger peak height and more excellent electrochemical performance. The research results have laid a good foundation for PAMAM-CDs used in electrochemical sensors. The high quality and riched abundant active group PAMAM-CDs was directly fixed on the electrodeposited gold nanoparticles(GNPs) and used to buid electrochemiluminescence sensor.In the third part of this paper. Based on the PAMAM-CDs/GNPs/GCE,anti-ketamine antibody(anti-ket) was linked to the PAMAM-CDs by glutaraldehyde(GLD) and anti-ket/PAMAM-CDs/GNPs/GCE was obtained. The film electrode was characterized by cyclic voltammetry(CV), electrochemical impedance spectroscopy(EIS) and electrochemiluminescence(ECL) techniques. We investigated the behavior of the ECL immunosensor and optimized for the conditions of the immune reaction.Then we used ECL immunosensor to detect ketamine. Under the optimal condition,the obtained ECL immunosensor showed that it had a lower detection limit(0.067ng/m L) with its concentrations ranging of 0.2~200 ng/m L. Compared with other similar immunosensor, it had a wider linear range and high sensitivity. Besides, the immunosensor had the advantages of high stability, good selectivity and nicer rebirth capability. This electrode sensor was used to detect actual samples and the satisfied result was obtained. |
PDF Full Text Request