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在适当的酸性介质中,秋水仙碱(COL)能与色氨酸(Trp)、酪氨酸(Tyr)和苯丙氨酸(Phe)等芳香族氨基酸反应并形成结合产物,此时将引起上述氨基酸的荧光发生猝灭,最大猝灭波长分别位于350nm(Trp),304nm(Tyr),284nm(Phe).其荧光猝灭值(ΔF)在一定范围内与秋水仙碱成正比.当用Trp和Tyr作探针时,荧光猝灭法测定秋水仙碱具有高灵敏度,其检出限分别为15.1ng/mL(3.78×10-8mol/L)和19.8ng/mL(4.96×10-8mol/L).文中研究了适宜的反应条件和影响因素,考察了共存物质的影响,表明方法有良好的选择性,可用于秋水仙碱的测定.文中讨论了复合物的组成、结合力和结合模式.通过温度的影响以及Stern-Volmer作图,判断该反应为静态猝灭反应,它们的结合常数(K)在25℃时分别为9.7×106(COL-Trp),8.9×106(COL-Tyr)和6.3×105(COL-Phe).其作用力主要是芳基堆集作用和氢键结合作用,而芳基堆集作用是发生荧光猝灭的主要原因.
Colchicine (COL) reacts with aromatic amino acids such as tryptophan (Trp), tyrosine (Tyr), and phenylalanine (Phe) in a suitable acidic medium to form a conjugate product that will cause The fluorescence of the above amino acids was quenched, and the maximum quenching wavelength was at 350 nm (Trp), 304 nm (Tyr) and 284 nm (Phe), respectively, and its fluorescence quenching value (ΔF) was proportional to colchicine within a certain range Trp and Tyr as probes, the detection limit of colchicine by fluorescence quenching was 15.1ng / mL (3.78 × 10-8mol / L) and 19.8ng / mL (4.96 × 10-8mol / L) .In this paper, the appropriate reaction conditions and influencing factors were studied, and the influence of coexisting substances was investigated, indicating that the method has good selectivity and can be used for the determination of colchicine.The composition, binding force and binding Model.The quenching reaction was judged to be static quenching by the influence of temperature and Stern-Volmer mapping.The binding constants (K) of them were 9.7 × 106 (COL-Trp) and 8.9 × 106 (COL- Tyr) and 6.3 × 105 (COL-Phe), respectively. The main forces are the aryl group stacking and the hydrogen bonding, while the aryl group stacking is the main reason for the fluorescence quenching.