title: Simultaneous determination of L- and D-methotrexate using a sequential injection analysis/amperometric biosensors system.
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.
authors: Department of Chemistry, University of Pretoria, Pretoria 0002, South Africa. raluca.stefan@chem.up.ac.za
authors: Raluca-Ioana
authors: RI
authors: Stefan
authors: Rahel Girmai
authors: RG
authors: Bokretsion
authors: Jacobus Frederick
authors: JF
authors: van Staden
authors: Hassan Y
authors: HY
authors: Aboul-Enein
mesh_terms: D000594:Amino Acid Oxidoreductases / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D045424:Complex Mixtures / Q000032:analysis / Q000737:chemistry; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004800:Enzymes, Immobilized; D004867:Equipment Design; D019544:Equipment Failure Analysis; D017022:Flow Injection Analysis / Q000295:instrumentation* / Q000379:methods; D006735:Horseradish Peroxidase / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000032:analysis / Q000737:chemistry; D050830:L-Amino Acid Oxidase; D008727:Methotrexate / Q000032:analysis* / Q000737:chemistry*; D008832:Microchemistry / Q000295:instrumentation / Q000379:methods; D009862:Online Systems; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013237:Stereoisomerism
chemical_list: D045424:Complex Mixtures; D004800:Enzymes, Immobilized; D006861:Hydrogen Peroxide; D006735:Horseradish Peroxidase; D000594:Amino Acid Oxidoreductases; C023061:L-glutamate oxidase; D050830:L-Amino Acid Oxidase; D008727:Methotrexate