【摘要】 建立了一种基于核酸适体(Aptamer)构象效应和荧光探针噻唑橙(TO)为荧光分子开关进行钾离子检测的光学方法。室温下钾离子可与Aptamer结合形成G-四面体结构,使双链解链变为四面体结构和单链,从而导致TO荧光强度降低。考察了TO浓度、反应温度及反应时间的影响。在最佳实验条件下,钾离子浓度在1.0×10-6~2.0×10-4mol/L范围内与荧光强度降低比率(IF0-IF)/I0F呈良好的线性关系,检出限达3.3×10-7mol/L;对Li+、Na+、Ca2+、Mg2+、NH4+离子进行对照实验的结果表明,该方法不仅具有较好的灵敏度和选择性,且无需荧光标记,操作简单、成本低。将该方法用于药品中钾离子含量的测定,其结果与原子吸收法一致。更多还原

【Abstract】 An optical method for the detection of potassium ion based on the conformational change of aptamer and fluorescent probe thiazole orange(TO)was reported.Anti-K+ aptamer was hybridized with its complementary strand which has a single base mutation and is shorter than aptamer.TO exhibited stronger fluorescence when it interacted with the double-strand DNA mentioned above.The fluorescence emission intensity of TO decreased when double-strand DNA was dehybridized due to the formation of G-quadruplex structure and single strand DNA in the presence of K+.The influences of TO concentration,temperature and time on the sensing of K+ were investigated.Under the optimum reaction conditions,a good linear relationship was found between the fluorescence decreasing ratio(I0F-IF)/I0F and the potassium ion concentration in the range of 1.0×10-6-2.0×10-4 mol/L,and a sensitive detection limit of 3.3×10-7 mol/L was obtained.Contrast experiments with other ions such as Li+,Na+,Ca2+,Mg2+ and NH+4 showed that this method was label-free,simple and economical,and could be used for the determination of K+ in potassium penicillin-V tablets with good sensitivity and specificity for K+.The results obtained by this method were in agreement with those from atomic absorption spectrophotomertic analysis.更多还原