Novel iron (III) phthalocyanine derivative functionalized semiconductor based transducers for the detection of citrate

• Novel electrochemical iron phthalocyanine derivative based sensors using Si-p/SiO2/Si3N4 and ISFET structures.
• Successful miniaturization process for the semiconductor based transducer.
• Study of the developed chemical sensors performance towards the detection of citrate.
• Wide span linear range of detection (10−6–10−1 M) with a detection limit of about 10−7 M.
• Modelisation of experimental data using the enhanced site binding model and TopSPICE ISFET/MEMFET macromedel.

In the present work, we report a novel citrate-selective sensor based on iron (III) phthalocyanine chloride-C-monoamido-Poly-n-Butyl Acrylate (Fe(III)MAPcCl-P-n-BA) modified silicon nitride and Ion sensitive field effect transistor (ISFET) structures for the electrochemical determination and estimation of the pathophysiological range of citrate. The developed capacitive sensor based on Fe(III)MAPcCl-P-n-BA had a Nernstian sensitivity of (−20.2 ± 1.3) mV/decade with a detection limit of about 7 × 10−7 M and a linear range from 10−6 M to 10−1 M (RSD = 6.2%). Then, the performance of the Fe(III)MAPcCl-P-n-BA functionalized ISFET structure towards the detection of citrate has been investigated. A Nernstian sensitivity of about (−19.8 ± 1.0) mV/decade in the range from 10−6 M to 10−1 M was achieved (RSD = 4.8%) which covered the pathologically important clinical range of citrate. The detection limit was about 4 × 10−7 M. The number of available recognition sites Ns and the complexation constant pK were calculated using the enhanced site binding model. A side by side comparison of the developed chemical sensors based on electrolyte-insulator-Semi conductor (EIS) and ISFET structures showed similar characteristics which proves the successful miniaturization of the semiconductor based transducer. The obtained experimental data of the Fe(III)MAPcCl-P-n-BA functionalized ISFET structure were used to validate the TopSPICE ISFET/MEMFET macromodel. The obtained theoretical sensitivity was in good agreement to the experimental one which proves the successful design of the developed ISFET/MEMFET macromodel.

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