Roe J N, Szoka F C, Verkman A S
Department of Bioengineering, University of California, San Francisco 94143.
Analyst. 1990 Apr;115(4):353-8. doi: 10.1039/an9901500353.
A fluorescence fibre optic sensor has been developed for measurement of the potassium concentration in aqueous solution based on the change in optical absorbance of the hydrophobic indicator 7-decyl-2-methyl-4-(3',5'-dichlorophen-4'-one)indonaphth-1-o l (MEDPIN). The sensor was constructed by dipping the distal end of a single optical fibre in a poly(vinyl chloride) (PVC) coating solution containing MEDPIN, a plasticiser, the ionophore valinomycin and the fluorescent dye 1,1'-dioctadecyl-3,3,3',3'-tetramethylindodicarbocyanine perchlorate [DilC18(5)]. The change in the absorbance of MEDPIN induced by potassium was detected from the quenching of the fluorescence of DilC18(5) due to energy transfer. Glass slides dipped in the PVC coating solution were used to establish the optical properties of the sensor. The potassium concentration was detected by the absorbance of MEDPIN at 650 nm and by the quenching of the DilC18(5) fluorescence by MEDPIN. The fluorescence intensity and lifetime of DilC18(5) decreased by ca. 40% with the addition of 33 mM KCl, indicating a resonance energy transfer mechanism. Experiments with the fibre optic sensor showed a decrease in the fluorescence of 57% with increasing potassium concentration (0-5 mM) at pH 7.45. The potassium concentration giving a 50% decrease in the fluorescence (Kd) for the most sensitive probe was 0.05 mM KCl. The value of Kd was increased to 1.3 mM when the plasticiser was changed from 2-nitrophenyl octyl ether to tris(2-ethylhexyl)phosphate; however, the 90% response time increased from 10 s to 4.2 min.(ABSTRACT TRUNCATED AT 250 WORDS)
基于疏水性指示剂7-癸基-2-甲基-4-(3',5'-二氯苯-4'-酮)茚并萘-1-醇(MEDPIN)的吸光度变化，开发了一种用于测量水溶液中钾离子浓度的荧光光纤传感器。该传感器通过将单根光纤的远端浸入含有MEDPIN、增塑剂、离子载体缬氨霉素和荧光染料1,1'-二十八烷基-3,3,3',3'-四甲基吲哚二碳菁高氯酸盐[DilC18(5)]的聚氯乙烯(PVC)涂层溶液中构建而成。由于能量转移，通过DilC18(5)荧光猝灭检测钾离子诱导的MEDPIN吸光度变化。将载玻片浸入PVC涂层溶液中用于确定传感器的光学性质。通过MEDPIN在650 nm处的吸光度以及MEDPIN对DilC18(5)荧光的猝灭来检测钾离子浓度。添加33 mM KCl时，DilC18(5)的荧光强度和寿命降低了约40%，表明存在共振能量转移机制。光纤传感器实验表明，在pH 7.45条件下，随着钾离子浓度(0 - 5 mM)增加，荧光降低了57%。对于最灵敏的探针，使荧光降低50%的钾离子浓度(Kd)为0.05 mM KCl。当增塑剂从2-硝基苯基辛基醚变为三(2-乙基己基)磷酸酯时，Kd值增加到1.3 mM；然而，90%响应时间从10秒增加到4.2分钟。(摘要截断于250字)
