Biosensors and Bioelectronics 2003-11-30

Simultaneous determination of L- and D-methotrexate using a sequential injection analysis/amperometric biosensors system.

Raluca-Ioana Stefan, Rahel Girmai Bokretsion, Jacobus Frederick van Staden, Hassan Y Aboul-Enein

Index: Biosens. Bioelectron. 19(3) , 261-7, (2003)

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Abstract

A sequential injection analysis (SIA) is proposed for the simultaneous determination of L- and D-methotrexate (Mtx) using amperometric biosensors as detectors. A SIA system is proposed due to the highest precision and accuracy and lower consumption of sample and buffer. The amperometric biosensors used as detectors in SIA system were based on L-amino acid oxidase (L-AAOD) or/and L-glutamate oxidase (L-Glox) and horseradish peroxidase (HRP) for the assay of L-Mtx and D-amino acid oxidase (D-AAOD) and HRP for the assay of D-Mtx were selected. The linear concentration ranges are of pmol/l to nmol/l magnitude order, with very low limits of detection. The SIA/biosensors system can be used reliably on-line in synthesis process control, for the simultaneous assay of L- and D-Mtx with a frequency of 34 samples per hour.