CAJ | 학술논문

采用原位电化学表面增强拉曼光谱(EC-SERS)和电化学还原方法,研究了内消旋-2,3-二巯基丁二酸(DMSA)在活化的银电极上的吸附行为。通过模型分子 DMSA 进行结构优化的密度泛函理论计算,得到了理论拉曼光谱。在相同的 DMSA 自组装时间条件下,其在 Ag 电极表面的覆盖度倒数与溶液浓度倒数成线性关系,说明 DMSA 单分子层在活性 Ag 表面的化学吸附遵循 Langmuir 等温吸附模型。在酸性介质中,DMSA 浸置自组装50 min 后,SERS 峰强趋于稳定,达到了该浓度下的动态吸附平衡。 EC-SERS 信号随施加电位的负移逐渐减弱至基本消失。通过计算探针分子 DMSA 在不同电位下的增强因子(EF),指出较负电位下存在着还原/脱附作用,使得 Ag 表面的拉曼活性降低,尤其在小于-0.4 V 的还原电位时,增强因子显著减小。
채용원위전화학표면증강랍만광보(EC-SERS)화전화학환원방법,연구료내소선-2,3-이구기정이산(DMSA)재활화적은전겁상적흡부행위。통과모형분자 DMSA 진행결구우화적밀도범함이론계산,득도료이론랍만광보。재상동적 DMSA 자조장시간조건하,기재 Ag 전겁표면적복개도도수여용액농도도수성선성관계,설명 DMSA 단분자층재활성 Ag 표면적화학흡부준순 Langmuir 등온흡부모형。재산성개질중,DMSA 침치자조장50 min 후,SERS 봉강추우은정,체도료해농도하적동태흡부평형。 EC-SERS 신호수시가전위적부이축점감약지기본소실。통과계산탐침분자 DMSA 재불동전위하적증강인자(EF),지출교부전위하존재착환원/탈부작용,사득 Ag 표면적랍만활성강저,우기재소우-0.4 V 적환원전위시,증강인자현저감소。
Meso-2,3-dimercaptosuccinic acid (DMSA) assembled on activated silver electrode was analyzed by in-situ electrochemical surface-enhanced Raman scattering (EC-SERS) and electro-re-duction. Density functional theory calculations had been carried to obtain the molecular optimization structure and theoretical Raman spectra. The reduction peak of S-Ag derived from DMSA on activa-ted Ag was at - 0. 4 V (vs. SCE). Under the same self-assembly time, a linear regression fit be-tween the reciprocals of surface coverage and solution concentration was investigated by using linear sweep voltammetry ( LSV), which indicating that DMSA monolayer adsorbed on surfactivity Ag obeys the Langmuir isothermal adsorption equation. The maximum surface coverage of DMSA on Ag electrode from LSV was 5. 41 × 10 - 10 mol·cm - 2 , and the adsorption coefficient was 3. 74 × 103 L· mol - 1 . The stabilized SERS signals of target concentrations were detected after 50 min for an adsorp-tion equilibrium at acid condition. It was found that EC-SERS intensities became weaker, and the peaks eventually disappeared when the potential was negatively shifted. A single molecule area for DMSA adsorbed on Ag substrates was 0. 389 nm2 , and the effective depth of 785. 18 nm laser beam irradiated to the ideal solution focusing surface was 3. 461 μm. Furthermore, the performancechange of silver electrode was proposed by calculating enhancement factor (EF) at different poten-tials. As a result of reduction / desorption behavior of DMSA at relatively negative potentials, EF of probe molecule on silver was significantly reduced and the Raman enhanced activity was lost espe-cially the potential value was less than - 0. 4 V.