Plumbagin: A New Route to the Electroanalytical Determination of Cystine

Abstract

Abstract The interaction between 5‐hydroxy‐1,4‐naphthoquinone and cysteine was found to give a clearly resolved voltammetric signature that could be used as an electrochemical assay for the thiol. A structure‐function study assessed the nature of the resulting voltammetric profile and the highly selective response to cysteine. The translation of the system as the basis of an assay for the determination of cystine was investigated using mercaptopropanol as the in situ reducing agent. The lack of response to the latter and high recovery performance of the label opens up a new direction for the one pot, mercury free determination of cystine.