Screen-Printed Glucose Oxidase-Based Biosensor for Inhibitive Detection of Heavy Metal Ions in a Flow Injection System

A screen-printed electrode amperometric biosensor based on glucose oxidase was successfully used for the inhibitive detection of a wide set of heavy metal ions (Hg²⁺, Ag⁺, Cu²⁺, Cd²⁺, Co²⁺, Ni²⁺) in a flow-injection system. The present work represents a successful way of combining advantages coming from Flow Injection Analysis (FIA) with ones deriving from the use of screen-printing technology in the development of an enzyme inhibition based biosensor. One of the most novel and attractive features of the developed system is the easy and rapid response recovery that does not require any treatment with regenerating reagents. Moreover, sensor response was satisfactory in terms of linear range, limit of detection (LOD), sensitivity and standard deviation. In particular, Hg²⁺, Cu²⁺, Cd²⁺, Co²⁺, Ni²⁺ have been successfully revealed at ppm concentration while LOD for Ag⁺ is in the ppb range. Also the application of the system in glucose detection was satisfactory. Glucose concentrations in the range 0.5–50 mM were detected and sensor response to glucose 10 mM revealed to be stable for 4 hours analysis after being subject to 20 subsequent injections.