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Flow‐injection–electrochemical oxidation fluorimetry for determination of methotrexate
Author(s) -
Chen Suming,
Zhang Zhujun,
He Deyong,
Hu Yufei,
Zheng Huzhi,
He Chao
Publication year - 2007
Publication title -
luminescence
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.428
H-Index - 45
eISSN - 1522-7243
pISSN - 1522-7235
DOI - 10.1002/bio.968
Subject(s) - detection limit , methotrexate , chemistry , fluorescence , electrochemistry , linear range , carboxylic acid , fluorescence spectroscopy , chromatography , calibration curve , analytical chemistry (journal) , electrode , organic chemistry , physics , immunology , biology , quantum mechanics
A novel fluorimetric model of on‐line electrochemical oxidation for the determination of methotrexate (MTX) is described in this paper. The method was based on the oxidation of MTX to a highly fluorescent product, 2,4‐diaminopteridine‐6‐carboxylic acid, by constant potential in the electrochemical oxidation flow cell. Stopped‐flow techniques were employed. Under optimal conditions, the fluorescence intensity of 2,4‐diaminopteridine‐6‐carboxylic acid was measured at excitation and emission wavelengths of 380 and 465 nm, respectively. The calibration graph was linear over concentrations of methotrexate in the range 2.0 × 10 −7 –1.0 × 10 −5 g/mL, with a detection limit of 5.2 × 10 −8 g/mL (3 σ ). The method has been successfully applied to the determination of methotrexate in human urine samples and showed a percentage recovery in the range 94.3–102.5%. Copyright © 2007 John Wiley & Sons, Ltd.