Automated Preparation Of Au-Ag Alloy Nanoparticles And Construction And Application Of EC-SERS Probes

Since the first surface-enhanced Raman scattering（SERS）spectra were obtained from electrochemically roughened silver electrodes,the use of electrochemical（EC）methods for the modulation of substrate or Raman label molecules has been an effective means of obtaining high-resolution SERS spectra.Electrochemical surface-enhanced Raman scattering（EC-SERS）has become a commonly used characterisation tool to meet the growing need to characterise complex systems,ensuring significant advances in fields such as advanced materials and life sciences.EC can improve SERS sensing in a number of ways,for example by providing higher selectivity through surface charge manipulation,ensuring controlled EC on the adsorption of analytes or interferers/surface desorption of substrate components,achieving maximum substrate surface coverage of target analytes,simulating a more biologically relevant environment,surface activation by oxidation/reduction cycling（ORC）,improving reproducibility,etc.SERS is now successfully used as an in situ vibrational characterisation tool that provides mechanical and dynamic information at the electrode/solution interface at the molecular or atomic level,and cross-validation of data is possible when quantified by EC and SERS.As society develops and science improves,it will become inevitable that more and more machines will perform to replace or assist human work,and this has become a hot topic of current research,with automated equipment being gradually promoted from all aspects.At present,in the laboratory nanoparticle synthesis stage,the main reliance on manual synthesis,the entire experimental process requires human monitoring,not only inefficient and often due to improper manual operation led to synthesis experiment failure.To address the problems of the prior art,we provide an automated method for the synthesis of gold and silver alloy nanoparticles,which is characterised by automation,functional multiplexing and good scalability.Therefore,we designed an automated device for the synthesis of Au-Ag alloy nanoparticles and applied it to the EC-SERS study of dopamine.The first device was designed to replace the manual synthesis of gold and silver alloy nanoparticles,and this device is based on the synthesis steps of gold and silver alloy nanoparticles,and the STC89C52 microcontroller was used to control the stepper motor,temperature sensor and other modules to achieve the sample The device is based on the synthesis of gold and silver alloy nanoparticles.The device is based on the synthesis of gold and silver alloy nanoparticles,and the STC89C52 microcontroller controls the stepper motor,temperature sensor and other modules to control the addition of samples and the reaction temperature.The device consists of two main modules,the control module and the chemical reaction device module.Once the hardware module and the circuit design were completed,the software part was next.We programmed the nanoparticle synthesis procedure using Keil u Vision4software and finally completed the design of the automated gold and silver alloy nanoparticle synthesis device through trial and debugging.Next,using the coffee ring effect,active substrates with SERS response were prepared by dropwise addition of a highly concentrated Au-Ag nanoparticle solution on ITO conductive glass sheets and then dried,and the Au-Ag nanoparticles were characterised by transmission electron microscopy（TEM）,dark field microscopy（DFM）,ultraviolet-visible absorption spectroscopy（UV-vis）high-resolution transmission electron microscopy（HRTEM）and other means.Au-Ag nanoparticles were characterised and the results showed good morphology.The good SERS reproducibility and homogeneity were verified by measuring the SERS signal of 4-mercaptobenzoic acid（4-MBA）at different positions on the substrate.The substrate on the ITO glass sheet can also be used as a working electrode for EC-SERS,and we examined the properties of dopamine（phenol）and dopamine（benzoquinone）on the Au-Ag surface by combining electrochemistry and SERS.The increase and decrease in SERS intensity at 1270,1335 and 1455 cm^-1 are modulated by H₂O₂ and GSH,so that the H₂O₂ and GSH concentrations could be broadly quantified by this approach.Finally,the potential-dependent changes in the redox of dopamine at the electrode were also probed by the constant potential method,providing new evidence for the study of its redox properties.