MOE Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, 510631 Guangzhou, China.
MOE Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University, 510631 Guangzhou, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2014 Mar 25;122:65-74. doi: 10.1016/j.saa.2013.11.060. Epub 2013 Nov 21.
In this paper, surface-enhanced Raman scattering (SERS) spectra of maleic hydrazide (MH, 6-hydroxy-3(2H)-pyridazinone) were studied by using citrate-reduced gold colloidal nanoparticles. Comparisons between the prominent SERS bands and the precise mode descriptions predicted through density functional theory (DFT) simulations at the B3LYP/6-311++g(d,p) level allowed an in-depth orientation analysis of the adsorbed species on gold surfaces. And main forms of hydrogen bonds in the solid state of MH were also determined to be O-H⋯O. Furthermore, the effects of concentration and pH on the SERS spectra of the molecule were discussed. It is found that with the different adsorbate concentration, the SERS spectra of MH show significant changes in their features, indicating different orientations and adsorption sites of the molecule on the gold colloidal surface. The SERS and absorption spectra under different pH conditions show that a basic environment leads to the deprotonation of N2 and the nearly parallel orientation of the MH molecule on the gold surface. Moreover, the enhanced characteristic bands were observed at MH concentrations down to about 1 ppm with the gold colloids, demonstrating a potential of the technique in the analysis of MH residues.
本文采用柠檬酸还原的金胶体纳米粒子研究了马来酰肼（MH，6-羟基-3（2H）-哒嗪酮）的表面增强拉曼散射（SERS）光谱。通过在 B3LYP/6-311++g（d，p）水平上进行密度泛函理论（DFT）模拟的突出 SERS 带和精确模式描述之间的比较，允许对吸附在金表面上的物种进行深入的取向分析。并且还确定了 MH 固体中氢键的主要形式为 O-H⋯O。此外，还讨论了分子浓度和 pH 值对其 SERS 光谱的影响。结果发现，随着吸附物浓度的不同，MH 的 SERS 光谱在其特征上表现出明显的变化，表明分子在金胶体表面上的不同取向和吸附位点。在不同 pH 值条件下的 SERS 和吸收光谱表明，碱性环境导致 N2 的去质子化和 MH 分子在金表面上近乎平行的取向。此外，在金胶体存在下，在 MH 浓度低至约 1ppm 时观察到增强的特征带，表明该技术在 MH 残留分析中的潜在应用。
