Dissolved ammonia sensing in complex mixtures using metalloporphyrin-based optoelectronic sensor and spectroscopic detection

摘要

We demonstrate dissolved ammonia (NH_3) sensing in complex mixtures using an optoelectronic sensor comprising a composite sensing material based on a metalloporphyrin zinc tetraphenylporphyrin (ZnTPP) and spectroscopic detection. The metalloporphyrin dye is incorporated within ion-exchange polymeric microbeads arranged in a microfluidic array. Spectroscopic analysis at multiple wavelengths allows sensitive detection in complex backgrounds. The sensor shows preferential sensitivity to ppm levels of concentrations of NH_3 dissolved in water, as well as in human saliva, making it relevant for medical diagnostic applications (e.g. detection of stomach bacterial infections). The microfluidic platform and a miniaturized optical arrangement provide a potential for the development of a portable low-power sensor for detection of dissolved ammonia for a variety of applications.