Electrochemical study on transfer reaction of ionizable cefotiam across a water/1,2-dichloroethane interface and drug sensing applications

In this article, electrochemical investigation of the transfer reaction of ionizable cefotiam (CTM), an antibiotic molecule across a polarized water/1,2-dichloroethane (water/1,2-DCE) interface was studied. Ion partition diagram providing the preferred charged form of CTM in either water or 1,2-DCE phase was established via the voltammetric evaluation of the transfer process of differently charged CTM species depending upon the pH variation of aqueous solutions. Thermodynamic information including the formal transfer potential and formal Gibbs transfer energy values in addition to important pharmacokinetics including partition coefficients of ionizable CTM were also evaluated. In particular, the current associated with the transfer of CTM present at pH 3.0 aqueous solution proportionally increased with respect to the CTM concentration which was further used for developing CTM sensitive ion sensor. In order to improve the portability and convenient usage, a single microhole interface fabricated in a supportive polyethylene terephthalate film was used of which hole was filled with a polyvinyl-chloride-2-nitrophenyloctylether (PVC-NPOE) gel replacing 1,2-DCE, a toxic organic solvent. A dynamic range of 1-10 µM CTM was obtained.