Kinetics of the chemical and electrochemical, reversible oxidation of bis(dithiooxalato-S,S')cuprate(II), [Cu(Dto)2]2-. A facile, light-activated, intramolecular electron transfer and cleavage of the carbon-carbon bond in the coordinated Dto ligands in the [Cu(Dto)2]- anion

Determination of the pharmaceutical peptide TP9201 by post-column reaction with copper(II) followed by electrochemical detection

An electrochemical detection method was applied to the determination of the synthetic peptide TP9201 (Telios Pharmaceuticals). The method utilizes reversed-phase HPLC, followed by post-column formation of Cu(II)-peptide complexes to render peptides electrochemically active via the Cu(III/II) couple. TP9201 is cyclic and N-amidated; the lack of a free amine precludes the use of typical fluorescent labeling reagents. Neither the cyclic structure nor the N-amidation prevented the copper complexation reaction, however. The detection limit in bovine serum was 20 nM, limited by interfering sample peaks, and the detector response was linear in a range 10-400 nM.