Voltammetric determination of leucovorin using silver solid amalgam electrode

The voltammetric behavior of leucovorin (LV), as an important and stable reduced metabolite of folic acid, has been investigated on polished (p-AgSAE) and mercury meniscus modified (m-AgSAE) silver solid amalgam electrodes in this paper. LV, after its reverse electrochemical oxidation, can be reduced in two reduction steps in an acidic medium on both electrodes used. The first reduction peak (E-p = -400 mV) can be used for determination of LV. Differential Pulse Voltammetry (DPV) was applied for monitoring voltammetric behavior of LV on both working electrodes. Elimination voltammetry with linear scan was applied for elucidation of the reaction mechanisms. The limits of detection were calculated as 2.2 x 10(-8) mol L-1 (t(acc) = 60 s) for m-AgSAE and 5.0 x 10(-8) mol L-1 (t(acc) = 100 s) for p-AgSAE. The proposed method was applied for LV determination in the pharmaceutical preparation which has been commonly used during methotrexate therapy. (C) 2011 Published by Elsevier Ltd.