Measurement of high acidity using a renewable-reagent fiber optic sensor

摘要

The renewable-reagent sensor concept was initially developed to address shortcomings in fiber optic chemical sensors dependent on immobilized, reversible reagents to produce analyte specific responses. The renewable-reagent sensor incorporates semi-selective membranes, analyte specific reagents and remote spectroscopic detection to extract selective responses. While renewable-reagent fiber optic sensor have been demonstrated for a number of chemical sensing applications, the transfer of laboratory prototypes to real world applications require devices which oversample the measurement matrix to differentiate among environmental and analyte specific response components. For example, optical sensor which acquire broadband rather than single wavelength spectroscopic data provide diagnostics regarding the identity of and measurement error associated with matrix interferences. The following describes the fabrication and evaluation of two renewable-reagent fiber optic sensor designs for the measurement of HNO(sub 3) in the 0.1 M to 10.0 M concentration range. Both sensor designs employ an internal pH indicator reagent and broadband visible spectroscopic detection to characterize HNO(sub 3) concentration.