摘要
三甲胺(Trimethylamine,TMA)是衡量畜禽水产及其制品中腐败程度重要指标。表面增强拉曼光谱技术在纳米级ⅠB族金属粗糙结构上具有极高检测灵敏度。目前,TMA表面增强拉曼光谱实验研究还未见报道,所以理论得到TMA表面增强拉曼谱图并和实验结果对比具有重要意义。将表面增强拉曼光谱与密度泛函理论(DFT)结合,研究TMA在银表面的吸附行为,通过不同吸附方式确定TMA与银团簇作用位点。优化得到TMA分子与银团簇形成的复合物Agn(n=1,3,5,6,7,8,10)的稳定构型以及SERS响应,对TMA振动频率进行全面归属,结果表明,TMA与银团簇形成较稳定复合物,且TMA中N原子优先吸附在银团簇表面,并通过N垂直于银表面,符合化学增强机理。对比不同尺寸银团簇对TMA表面增强拉曼光谱的影响,表明一定范围内拉曼强度随着配位银原子的增加随之加大,在Ag3-TMA峰强达到最大值39.75,而此后银团簇尺寸加大反而抑制了表面增强拉曼效应,使强度逐渐下降。
Trimethylamine(TMA)is an important indicator to measure the degree of spoilage in aquatic animals including their products and meat products.Surface-enhanced Raman spectroscopy has extremely high detection sensitivity on the rough nano-scale structure ofⅠB group metals.The surface-enhanced Raman spectroscopy research on TMA has not been reported,so it is of great significance to calculate surface-enhanced Raman spectra of TMA and compare them with experimental results.The behaviors of TMA adsorbed on silver surface were studied by surface-enhanced Raman spectroscopy combined with density functional theory(DFT),the optimal coordination site between Ag and TMA was determined by different adsorption methods.The stable conformation and SERS response of the complex TMA-Agn(n=1,3,5,6,7,8,10)were optimized and obtained,and the vibration frequencies of TMA were assigned.The results showed that trimethylamine and silver clusters formed relatively stable complexes,and N atom of TMA preferentially adsorbed on the surface of silver clusters which was perpendicular to the silver surface,in accordance with the chemical enhancement mechanism.By comparing different size of silver clusters influence on surface-enhanced Raman spectra of TMA,it was suggested that the Raman intensity increased with the increase of Ag atoms in a certain range and reached the maximum value of 39.75 at the Ag3-TMA,then the increase of silver cluster size inhibited the surface-enhanced Raman effect and the intensity decreased gradually.
作者
杨睿颖
朱秋劲
白晶
陈玉芹
龙久铃
YANG Rui-ying;ZHU Qiu-jin;BAI Jing;CHEN Yu-qin;LONG Jiu-ling(Guizhou Province Key Laboratory of Agricultural and Animal Products Processing and Storage, School of Liquor and Food Engineering,Guizhou University,Guiyang 550025,China)
出处
《化学研究与应用》
CAS
CSCD
北大核心
2021年第5期920-926,共7页
Chemical Research and Application
基金
贵州省科技计划项目(黔科合支撑[2019]2374号)资助
贵州省高层次创新型人才培养项目(黔科合平台人才[2016]5662号)资助。
关键词
表面增强拉曼光谱
密度泛函理论
三甲胺
频率归属
surface-enhanced Raman spectroscopy
density functional theory
trimethylamine
vibrational assignments
