Real-Time Sensing of O-Phenylenediamine Oxidation on Gold Nanoparticles.

Ru-Jia Yu,Jing-Zhi Tian,Jia-Jia Sun,Yi-Tao Long,Heng Song,Da-Wei Li

doi:10.3390/s17030530

Abstract

Real-time monitoring of chemical reactions is still challenging as well as important to study reaction mechanisms and reaction kinetics. Herein, we demonstrated the real-time monitoring of o-phenylenediamine (OPD) oxidation on the surface of gold nanoparticles by surface-enhanced Raman spectroscopy (SERS). The oxidation mechanism and the reaction kinetics were investigated on the basis of the SERS spectrum variation and the related density functionalized theory calculation. It was shown that the oxidation of OPD in the presence of copper ions was a two-step process of the deprotonation of the amino group on the aromatic rings and the rearrangement of the electron cloud to a π-conjugated system, which may open a new door to comprehensively understand the reaction process.

Highlights

Monitoring and characterizing chemical reactions is of vital significance to study the mechanisms and kinetics during the reactions [1]
Many analytical methods have been used to investigate chemical reactions such as mass spectrometry, chromatography, localized surface Plasmon resonance, nuclear magnetic resonance spectroscopy, etc., while they generally can hardly provide in situ information on chemical reactions and have the disadvantages of limited sensitivity and slow response time
Due to the lack of a real-time analytical method, clearly understanding the the study of the oxidation process of OPD is of profound guiding significance, especially for OPD oxidation mechanism and reaction kinetics is still challenging

Summary

Introduction

Monitoring and characterizing chemical reactions is of vital significance to study the mechanisms and kinetics during the reactions [1] For this purpose, many analytical methods have been used to investigate chemical reactions such as mass spectrometry, chromatography, localized surface Plasmon resonance, nuclear magnetic resonance spectroscopy, etc., while they generally can hardly provide in situ information on chemical reactions and have the disadvantages of limited sensitivity and slow response time. Due to the lack of a real-time analytical method, clearly understanding the the study of the oxidation process of OPD is of profound guiding significance, especially for OPD oxidation mechanism and reaction kinetics is still challenging. Schematic representation of the real-time monitoring of OPD oxidation on the surface of Scheme 1. Schematic representation of the real-time monitoring of OPD oxidation on the surface of gold nanoparticles

ReagentsThe andreagents

SERS Spectra of OPD

DFT Calculation

Discussion

As demonstrated

Conclusions