This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A c c e p t e d M a n u s c r i p t 2 AbstractThe electrochemical oxidation mechanism of the anti-cancer drug and kinases inhibitor danusertib was studied by cyclic, differential pulse, square wave voltammetry and a glassy carbon electrode. Danusertib undergoes oxidation in a cascade mechanism and depending on the pH of the supporting electrolyte several oxidation peaks were observed. The number of electrons and protons involved in each oxidation step as well as the pK a ~ 10.0 were determined. The analytical determination of danusertib was carried out in pH = 7.0 by square wave voltammetry with LOD = 27.4 nM and UV-VIS spectrophotometry with LOD = 0.5 µM. Different electroactive centres of danusertib were identified through comparative studies with similar compounds such as imatinib and piperazine, and an oxidation mechanism of danusertib proposed.

The electrochemical behaviour of 2,8-dihydroxyadenine (2,8-DHA)-the main adenine oxidation product-has been investigated over a wide pH range at a glassy carbon electrode (GCE) using cyclic, differential pulse and square wave voltammetry. The oxidation of 2,8-DHA is a quasi-reversible process, pH dependent and occurs with the formation of a main oxidation product, P 2,8-DHA , that strongly adsorbs on the electrode surface. The reduction of 2,8-DHA also occurs and is a reversible process in the absence of molecular oxygen. In electrolytes with pH between 4 and 9 two consecutive reversible charge transfer reactions were identified. However, it was observed that O 2 interfered with the reductive electron transfer process of 2,8-DHA and that, in the presence of oxygen, the reduction of 2,8-DHA occurs at less negative potentials than in the absence of oxygen.

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