title: Detection of methotrexate in a flow system using electrochemical impedance spectroscopy and multivariate data analysis.
abstract: Methotrexate (MTX), a common pharmaceutical drug in cancer therapy and treatment of rheumatic diseases, is known to cause severe adverse side effects at high dose. As the side effect may be life threatening, there is an urgent need for a continuous, bed-side monitoring of the nominal MTX serum level in a patient while the chemical is being administered. This article describes a detection of MTX using a flow system that consists two modified gold electrodes. Interaction of MTX with the antibodies fixed on the electrode surface is detected by electrochemical impedance spectroscopy and evaluated using singular value decomposition (SVD). The key finding of this work is that the change in the electrode capacitance is found to be quantitative with respect to the concentration of MTX. Moreover a calibration curve constructed using the principal component regression method has a linear range of six orders of magnitude and a detection limit of 1.65 × 10(-10) M.
authors.affiliation: Department of Chemistry, Umeå University, SE 90187 Umeå, Sweden. Electronic address: solomon.tesfalidet@chem.umu.se.
authors.forename: Solomon
authors.initials: S
authors.lastname: Tesfalidet
authors.affiliation: Corpus Data & Image Analysis AB, Rålambsvägen 66 B, Suit 1408, SE 112 56 Stockholm, Sweden.
authors.forename: Paul
authors.initials: P
authors.lastname: Geladi
authors.affiliation: Department of Chemistry, Umeå University, SE 90187 Umeå, Sweden; Physical and Theoretical Chemistry Laboratory, Department of Chemistry, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Shimizu
authors.affiliation: Department of Chemistry, Umeå University, SE 90187 Umeå, Sweden.
authors.forename: Britta
authors.initials: B
authors.lastname: Lindholm-Sethson
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000032:analysis; D018501:Antirheumatic Agents / Q000032:analysis; D058266:Dielectric Spectroscopy / Q000379:methods*; D008727:Methotrexate / Q000032:analysis*; D015999:Multivariate Analysis
chemical_list: D000964:Antimetabolites, Antineoplastic; D018501:Antirheumatic Agents; D008727:Methotrexate
keywords: Calibration model; Complex number singular value decomposition; Flow cell; Gold electrode; Impedance spectrometry; Methotrexate