Research On Electrochemiluminescence Sensing Performance Based On Carbon-based Quantum Dots

At present,health issues have become a topic of increasing concern,and it is more and more important to detect some substances harmful to the human body through a method.In this thesis,carbon-based quantum dots are used as the luminescent substance and potassium persulfate is used as a co-reactant to conduct experiments.The mechanism of carbon-based quantum dots is explored to detect sunset yellow and dopamine by the electrochemiluminescence method.The pivotal research contents of this paper are as follows:（1）A co-reactant system of graphene quantum dots and potassium persulfate（K₃PO₄）was constructed,and the food pigment sunset yellow was detected by electrochemiluminescence method.The conditions of the graphene quantum dots for were optimized.Under the optimized conditions,different concentrations of sunset yellow test solutions were added.It was found that when the concentration of sunset yellow became great,the corresponding electrochemiluminescence intensity also was great.Within the concentration range of 0.0025-25μmol·L^-1,the logarithm of 0.4times sunset yellow concentration is linear with the corresponding electrochemiluminescence intensity.The linear curve equation is Y=1908.46X+27973.08（R²=0.98,X=Lg（0.4C）,Y=electrochemiluminescence intensity）,the detection limit is 7.6 nmol·L^-1.The selective detection of substances that may interfere with sunset yellow detection shows that the electrochemiluminescence method based on this system has a certain selectivity for sunset yellow detection.（2）A carbon quantum dot was synthesized by one-step hydrothermal method to detect dopamine by electrochemiluminescence method.Different from other hydrothermal methods,this hydrothermal method uses glucose and potassium phosphate as reaction raw materials,and can change the size of the synthesized carbon quantum dots by controlling the content of potassium phosphate.The higher the potassium phosphate content was,the tinyer the size of the synthesized carbon quantum dots was.Dopamine was detected under the best conditions.After adding dopamine,the luminous intensity of the original carbon quantum dot system is significantly reduced.When dopamine is added,possible reaction mechanism is energy transfer.Different concentrations of dopamine were detected by this method.It is found that the logarithm of the concentration of dopamine and the luminous intensity show an obviously certain linear law within the concentration range of 0.01-100μmol·L^-1.The linear curve equation is Y=-985.87X-6996.36（R²=0.98,X=Lg（C）,Y=electrochemiluminescence intensity）,the detection limit is 62nmol·L^-1.This method realizes the detection of dopamine within a certain concentration range.It is found that the system has a certain selectivity for the detection of dopamine because of the detection of interfering substances,for example uric acid and ascorbic acid.