Dual Electrode Liquid Chromatography-Electrochemical Detection (LCEC) for Platinum-Derived Cancer Chemotherapy Agents

Abstract

Trace methods of analysis and speciation have now been developed for a number of platinum derived anti-cancer chemotherapeutic agents, drugs such as: cis-dichloro diammine platinum (CDDP), cis-diammine-1,1-cyclobutane dicarboxylate platinum (CBDCA), and cis-dichloro-trans-dihydroxy diisopropylamine platinum (CHIP). It is possible to utilize parallel dual electrode operations for all three of these Pt derivatives, with overall improved analyte specificity and identification. At the same time, these approaches provide calibration plots of detector sensitivity as a function of the particular working electrode potentials in use via dual electrode LCEC. These response ratios as a function of the applied potentials then become quite unique for individual Pt compounds. By suitably selecting the operating electrode potentials in parallel operation, it is possible to alter the detectability of individual Pt analytes and to drastically vary the resultant LCEC chromatograms. The overall analyte selectivity possible via dual electrode LCEC surpasses that thus far possible via LC-polarographic reduction or single electrode LCEC operations. Glassy carbon as well as gold/mercury electrodes can readily be used for some of these Pt derivatives. These overall trace methods of analysis and speciation for the Pt anti-cancer agents have also been applied to plasma samples spiked with known levels of each drug. It is also possible to utilize these single or dual electrode approaches for the analysis of each of these Pt derivatives in cancer patients undergoing chemotherapy treatment.