Detection of diethyl chlorophosphate using a composite optical waveguide sensor

Abstract

A highly sensitive composite optical waveguide (COWG) sensor was developed by spin coating a thin membrane of rhodamine B hydrazide (RbH)–polyvinylpyrrolidone (PVP) onto a K⁺ ion-exchanged glass optical waveguide. The COWG sensor was used to detect diethyl chlorophosphate (DCP) vapor which is a typical simulant for organophosphorus pesticides and chemical weapon agents. The membrane is stable in air but exposure to DCP vapor at room temperature can result in rapid and reversible changes of absorbance (A) and refractive index (n₁) of this membrane. The sensor was found to exhibit a linear response to DCP vapor in the range of 0.026–26.32 × 10⁻⁶ (volume fraction). The sensor has a short response time, high sensitivity, and good reversibility.