锂离子选择性光电二极管传感装置的研究及在血清分析中的应用

将锂离子选择性中性载体和亲脂性pH指示剂结合在增塑的PVC膜中,pH缓冲液中锂离子浓度的变化将引起膜颜色的改变.将该膜涂覆在光电二极管光敏区并与发出锐线光的发光二极管组装在一起,构成了一种新型锂离子选择性传感装置.报道了这一传感装置的响应特性,探讨了临床分析应用的可能性.

Studies on Lithium Ion-selective Photodiode Based on Neutral Ionophores and Application in Blood Serum

Optical chemical sensors are becoming increasingly popular and a multitude of designs have been reported recently.All these devices rely on a light source and a detector.Optical fibres are often employed to bring the incident light to the detector.Spectral selectivity is achieved conventionally using monochromators.Here we report on a compact probe that consists of a photodiode coated with a poly (vinyl chloride) (PVC) sensitive membrane and a light emitting diode having a relatively narrow spectral output.The two diodes are embedded in a plastic barrel opposite each other and the photodiode can be dipped into solutions similar to an ion-selective electrode.ETH1810 and ETH 2439 were chosen as the lithium ion carrier and pHindicator, respectively.The ETH2439 shows an absorption band at 514 nm in the unprotonated form which changes to about 650 nm when protoned.The competitive binding of lithium ion and hydrogen ion will change the color of the PVCmembrane.The red light emitting diodes have a maximum output at 660 nm, so that the change can be adequately monitored.The sensor shows a linear response to lithium ion over the range of 1×10^-4-7.9 × 10^-2 mol/Lwith the same selectivity as in potentiometric system.By use of the standard-addition method, different serum samples containing Li⁺ in the clinical range were assayed with this photodiode sensor.