Rahmalia Winda, Fabre Jean-François, Usman Thamrin, Mouloungui Zéphirin
Université de Toulouse, INP-ENSIACET, LCA (Laboratoire de Chimie Agro-industrielle), 4 Allée Emile Monso, CS 44362, 31030 Toulouse Cedex 4, France; Departement of Chemistry, Mathematic and Natural Science, Tanjungpura University, Jl. Ahmad Yani, Pontianak 78124, West Kalimantan, Indonesia.
Université de Toulouse, INP-ENSIACET, LCA (Laboratoire de Chimie Agro-industrielle), 4 Allée Emile Monso, CS 44362, 31030 Toulouse Cedex 4, France.
Spectrochim Acta A Mol Biomol Spectrosc. 2014 Oct 15;131:455-60. doi: 10.1016/j.saa.2014.03.119. Epub 2014 Apr 13.
We describe here the effects of aprotic solvents on the spectroscopic characteristics of bixin. Bixin was dissolved in dimethyl sulfoxide, acetone, dichloromethane, ethyl acetate, chloroform, dimethyl carbonate, cyclohexane and hexane, separately, and its spectra in the resulting solutions were determined by UV-visible spectrophotometry at normal pressure and room temperature. We analyzed the effect of aprotic solvents on λmax according to Onsager cavity model and Hansen theory, and determined the approximate absorption coefficient with the Beer-Lambert law. We found that the UV-visible absorption spectra of bixin were found to be solvent dependent. The S0→S2 transition energy of bixin in solution was dependent principally on the refractive index of the solvents and the bixin-solvent dispersion interaction. There was a small influence of the solvents dielectric constant, permanent dipole interaction and hydrogen bonding occurred between bixin and solvents. The absorbance of bixin in various solvents, with the exception of hexane, increased linearly with concentration.
我们在此描述非质子溶剂对联囊壁红素光谱特性的影响。将联囊壁红素分别溶解于二甲基亚砜、丙酮、二氯甲烷、乙酸乙酯、氯仿、碳酸二甲酯、环己烷和己烷中，并在常压和室温下通过紫外可见分光光度法测定所得溶液中的光谱。我们根据翁萨格空腔模型和汉森理论分析了非质子溶剂对最大吸收波长的影响，并利用比尔-朗伯定律确定了近似吸收系数。我们发现联囊壁红素的紫外可见吸收光谱取决于溶剂。溶液中联囊壁红素的S0→S2跃迁能量主要取决于溶剂的折射率以及联囊壁红素与溶剂的色散相互作用。溶剂的介电常数、永久偶极相互作用以及联囊壁红素与溶剂之间的氢键作用影响较小。除己烷外，联囊壁红素在各种溶剂中的吸光度随浓度呈线性增加。
