Microsensing of plutonium with a glass optofluidic device

The cointegration of optical and microfluidic functions on chemically resilient borosilicate glass to provide microfluidic chemical analyses is described. An evanescent wave sensing chip containing a fluid channel of 21  μL is implemented to carry out absorption spectroscopy measurements in the near-infrared range. Microchip packaging allows to perform remote analysis of harsh chemical solutions in confined environments. Detection of plutonium(VI) in aqueous 1 mol/L nitric acid solutions is achieved on solutions ranging from 0.05 to 0.13 mol/L. Results showcase the validity of the proposed approach by obtaining a sensor calibration curve and chip resilience to highly concentrated strong acids and radioactive elements. This proof-of-concept opens the path to optimized devices with a lower limit of detection.