LAUSR

Abstract In this study, we report the synthesis of thermosensitive poly(N-vinylcaprolactam) semi-interpenetrated conductive polypyrrole microgels (PVCL/PPY semi-IPN MGs) for “on-off” switchable electrochemical sensing of carcinogenic nitrogen mustard drug chlorambucil (Leukeran™). The synthesized PVCL/PPY semi-IPN MGs modified electrode acts as a thermo-reversible switch-like sensor for the electrochemical oxidation of chlorambucil due to the temperature stimulus-response of PVCL. Cyclic voltammetry (CV) of chlorambucil at the PVCL/PPY semi-IPN MGs modified electrode manifest well-defined higher oxidation peak current when the electrolyte temperature is above the TLCST of PVCL, signifying the “on” state. This chlorambucil electro-oxidation peak current reduced below the TLCST of PVCL, signifying the “off” state. Repeatable “on-off” switching of the CV responses of chlorambucil at the PVCL/PPY semi-IPN MGs modified electrode was attained by controlling the electrolyte temperature. The proposed temperature-responsive switched sensor had a wide dynamic range (0.02 to 420 µM), excellent sensitivity, and a low detection limit of 1.98 nM for chlorambucil at 40 °C compared to 25 °C. Interestingly, the proposed sensor proves excellent selectivity for detecting chlorambucil in potential interference compounds. Moreover, the proposed method was successfully used to detect chlorambucil in human blood serum and human urine samples.