Martín Laura, Olives Ana I, del Castillo Benito, Martín M Antonia
Laboratorio de Técnicas Instrumentales, S. D. Química Analítica, Facultad de Farmacia, Universidad Complutense de Madrid, 28040-Madrid, Spain.
Luminescence. 2005 May-Jun;20(3):152-61. doi: 10.1002/bio.812.
The study of fluorescence quenching of the fluorophores allows the localization of the alkaloids (harmane and harmine) in the micelles (SDS, CTAB, Brij-35) to be established. In aqueous micellar solutions (SDS and Brij-35) at pH 13.0, emission corresponding to the neutral or zwitterionic forms can be observed. In the presence of CTAB (pH = 13.0) it was possible to observe the emission of anionic form. These species are not present in buffered aqueous solutions at these pH values. Bromide ion was added to the different surfactant solutions and the quenching effect was studied according to the Stern-Volmer equation. In the presence of SDS the quenching effect is considerably reduced compared to the aqueous solutions without surfactants, while for Brij-35 micelles were similar to those observed in homogeneous aqueous solution. For CTAB micelles a notable fluorescence quenching was observed for the different pH values studied. The fluorescence quenching studies show that the neutral species are associated inside the micelles, instead of the ionic species (cationic, zwitterionic or anionic) remaining on the surface of the micelles. The anionic surface of SDS micelles prevents the quenching effect by anionic quenchers for both neutral and charged species.
对荧光团荧光猝灭的研究使得能够确定生物碱（哈尔满和哈尔明）在胶束（十二烷基硫酸钠、十六烷基三甲基溴化铵、Brij - 35）中的定位。在pH值为13.0的水性胶束溶液（十二烷基硫酸钠和Brij - 35）中，可以观察到对应于中性或两性离子形式的发射。在十六烷基三甲基溴化铵存在下（pH = 13.0），可以观察到阴离子形式的发射。在这些pH值下，这些物种不存在于缓冲水溶液中。向不同的表面活性剂溶液中加入溴离子，并根据斯特恩 - 沃尔默方程研究猝灭效应。与没有表面活性剂的水溶液相比，在十二烷基硫酸钠存在下猝灭效应显著降低，而对于Brij - 35胶束，其与在均相水溶液中观察到的情况相似。对于十六烷基三甲基溴化铵胶束，在所研究的不同pH值下均观察到显著的荧光猝灭。荧光猝灭研究表明，中性物种在胶束内部缔合，而不是离子物种（阳离子、两性离子或阴离子）留在胶束表面。十二烷基硫酸钠胶束的阴离子表面可防止阴离子猝灭剂对中性和带电物种产生猝灭效应。
