PNNL

Abstract

Rapid and sensitive detection and quantification of trace and ultra-trace analytes is critical to environmental remediation, analytical chemistry and defense from chemical and biological contaminants. While affinity based electrochemical sensors have gained immense popularity, they occasionally are not able to meet the requirements of desired sensitivity and detection limits. Here, we demonstrate a complementary luminescence mode that can significantly enhance sensitivity of impedance or voltammetric electrochemical sensors. Our methodology involves using a redox probe, whose luminescence properties change upon changing the oxidation state. By tailoring the system such that these luminescence changes can be correlated with the capture of target analytes, we are able to significantly lower the detection limit and improve efficiency of detection compared to the electrochemical modes alone. Our proof-of-concept demonstration using a model system designed for Ca2+ capture, illustrated that the luminescent mode allowed us to lower the limits of detection by 3-orders of magnitude compared to the impedance or voltammetric modes alone without requiring any modification of electrode design or cell configuration.