Ultrasensitive and miniaturized ion sensors using ionically imprinted nanostructured films

Ion-Selective Electrodes in the Food Industry: Development Trends in the Potentiometric Determination of Ionic Pollutants

“…Using this approach, sub-nanomolar level detection has been achieved, even in complex media such as fruit juice, and the material composition can be tailored to overcome the current limitations in ion sensors. This technology has been recently applied to simple anions such as chloride, with a material composition able to overcome standard ion-selective electrodes, such as the Nernst sensitivity limit [234]. Moreover, they can be applied to complex ions where ligands have not been reported yet, including methylmercury [99].…”

Composite Silica‐Based Films as Platforms for Electrochemical Sensors

“…Among the potentiometric sensors, one can cite a carbon paste electrode modified with diazo-thiophenol-functionalized silica for the detection of Ag(I) (with LOD at 9.5×10 À 7 M), [252] or the selective potentiometric detection of chloride ions using an ultra-thin (300 nm thick) nanostructured film of porous silica grafted with amino-groups and gold nanoparticles. [253] A potentiometric biosensor for urea has been fabricated by immobilizing urease in a composite film made of silica and MWCNTs on ITO electrode, exhibiting a fast response time (10-25 s) with a sensitivity of 23 mV/decade in the concentration range extending from 0.02 to 1 mM. [254] Knowing that sol-gel films can be patterned on ISFETs by photo-assisted electrodeposition, [255] or deposited as ultrathin layers on p-type and n-type organic field effect transistors (OFETs) by spin-coating, [256] and that such films can be generated in the form of composites with organic compounds or polymers, [257][258][259] has opened the door to silica-based ISFET and OFET sensors.…”

“…Beside their use in amperometric/voltammetric devices, silica thin films are considered as prospective membranes for potentiometric sensors or ion‐selective field‐effect transistors (ISFET) exhibiting high sensitivity and requiring small sample volume. Among the potentiometric sensors, one can cite a carbon paste electrode modified with diazo‐thiophenol‐functionalized silica for the detection of Ag(I) (with LOD at 9.5×10 −7 M), [252] or the selective potentiometric detection of chloride ions using an ultra‐thin (300 nm thick) nanostructured film of porous silica grafted with amino‐groups and gold nanoparticles [253] . A potentiometric biosensor for urea has been fabricated by immobilizing urease in a composite film made of silica and MWCNTs on ITO electrode, exhibiting a fast response time (10–25 s) with a sensitivity of 23 mV/decade in the concentration range extending from 0.02 to 1 mM [254] .…”