Sànchez J, Del Valle M
Sensors and Biosensors Group, Department of Chemistry, Autonomous University of Barcelona, Edifici Cn, E-08193 Bellaterra, Catalonia, Spain.
Talanta. 2001 Jun 21;54(5):893-902. doi: 10.1016/s0039-9140(01)00348-4.
The preparation of a new ion-selective field-effect transistor (ISFET) based on a photocurable membrane sensitive to anionic surfactants is described. The membrane is formed by an urethane-acrylate matrix with 2-cyanophenyl octyl ether as the plasticiser. When compared to conventional ion-selective electrodes, the prepared ISFETs do not show significant differences in sensitivity and reproducibility (P=0.05). When calibrating with dodecylbenzenesulfonate (DBS(-)) the prepared ISFETs show a nernstian behaviour, with a slope of 57.5 mV per decade. The linear working range is 1.0x10(-3) to 3.0x10(-6) M DBS(-) and the detection limit is 1.2x10(-6) M. The response times were below 0.7 min in all cases (95% of the step change). As the application, photodegradation processes using titanium dioxide dispersions, were monitored for two common anionic surfactants: DBS(-), being aromatic, and the more alkylic dodecylsulfate, DS(-). The determination of surfactant concentration was performed following a standard addition methodology, using ISFETs as the sensors, and without any previous separation stages. The degradation kinetics in both cases are first-order processes, with half-life times (t(0.5)) of 31.5 min for DBS(-) and 52.0 min for DS(-).
本文描述了一种基于对阴离子表面活性剂敏感的光固化膜制备新型离子选择性场效应晶体管（ISFET）的方法。该膜由聚氨酯 - 丙烯酸酯基体与2 - 氰基苯基辛基醚作为增塑剂形成。与传统离子选择性电极相比，所制备的ISFET在灵敏度和重现性方面没有显著差异（P = 0.05）。用十二烷基苯磺酸盐（DBS(-)）校准后，所制备的ISFET呈现能斯特行为，斜率为每十倍变化57.5 mV。线性工作范围为1.0×10(-3)至3.0×10(-6) M DBS(-)，检测限为1.2×10(-6) M。在所有情况下响应时间均低于0.7分钟（阶跃变化的95%）。作为应用，使用二氧化钛分散体的光降解过程针对两种常见阴离子表面活性剂进行了监测：芳香族的DBS(-)和链烷基性更强的十二烷基硫酸盐DS(-)。采用标准加入法，以ISFET作为传感器，无需任何先前的分离步骤来测定表面活性剂浓度。两种情况下的降解动力学均为一级过程，DBS(-)的半衰期（t(0.5)）为31.5分钟，DS(-)的半衰期为52.0分钟。
