Abstract

The classical way to modify a gold electrode surface for immunosensor development is through self-assembly of functionalised thiols for subsequent attachment of antibodies. Here is described a new pathway for surface modification using a diazonium salt-based immunosensor for detection of methotrexate (MTX) with electrochemical immittance spectroscopy (EIS). The diazonium salt, 4-carboxybenzenediazonium tetrafluoroborate was synthesized using a diazotization reaction and characterized by IR and cyclic voltammetry (CV). The Au electrode was electrografted with diazonium and used for anti-MTX antibody immobilization. The EIS detection of MTX was studied with and without application of redox probe; Fe(CN)(6)(3-/4-). MTX could not be detected using Fe(CN)(6)(3-/4-) as redox probe, whereas EIS measurements without redox probe and analysis of the data with singular decomposition (SVD) gave good results. A multivariate calibration model showed good linear behavior on a logarithmic scale with a detection limit for MTX of 7 x 10(-12) mol L--(1).

Keywords

4-carboxybenzenediazonium tetrafluoroborate; Gold electrode; Antibody; Immnunosensor; Singular value decomposition; Cyclic voltammetry; Chronoamperometry; Electrochemical impedance spectroscopy

Published in

Journal of electroanalytical chemistry
2018, Volume: 812, pages: 235-243
Publisher: ELSEVIER SCIENCE SA

SLU Authors

• Geladi, Paul

  • Department of Forest Biomaterials and Technology, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Analytical Chemistry


Publication identifier

DOI: https://doi.org/10.1016/j.jelechem.2017.12.072

Permanent link to this page (URI)

https://res.slu.se/id/publ/96846