Fe(II), Ni(II), Cu(II), and Co(II) salen Schiff base complexes: Proposal for a voltammetric sensor to analyze cocaine hydrochloride and its interferents

Author(s)

Castro, Alex Soares ^{[1, 2]} ; Pinke Rodrigues, Caio Henrique ^{[2, 3]} ; Teles de Menezes, Matheus Manoel ^[4] ; Defendi da Silva, Ana Beatriz ^[1] ; Bruni, Aline Thais ^{[2, 3]} ; de Oliveira, Marcelo Firmino ^[1]

Affiliation

^[1] Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, Dept Quim, Grp Eletroquim Eletroanalit & Quim Forense, Ave Bandeirantes 3900, Ribeirao Preto, SP - Brazil

^[2] Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, Dept Quim, Lab Estudos Interdisciplinares Direito Quim, Ave Bandeirantes 3900, Ribeirao Preto, SP - Brazil

^[3] Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, Inst Nacl Ciencia & Tecnol Forense INCT Forense, Dept Quim, Ave Bandeirantes 3900, Ribeirao Preto, SP - Brazil

^[4] Inst Fed Educ Ciencia & Tecnol Sao Paulo, Campus Catanduva, Catanduva, SP - Brazil

• Document type: Journal article
• Source: FORENSIC CHEMISTRY; v. 25, AUG 2021.
• Web of Science Citations: 1

Abstract

Given the fast-growing demand for anti-trafficking measures, this article investigates the development of voltammetric sensors for the oxidation of cocaine hydrochloride on the surface of carbon paste electrodes chemically modified with Schiff base complexes and their potential use for cocaine detection and quantification in seized samples. Voltammetric analyses revealed that {[}CoII(salen)] displayed amperometric and thermal stability, was uniformly distributed on the electrode surface, was only degraded at temperatures above 300 degrees C, and did not undergo passivation in acid medium. The {[}CoII(salen)]-modified voltammetric sensor gave error below 10%, an improvement on HPLC. SIMCA chemometric analyses predicted the group belonging to cocaine hydrochloride and its interferents effectively, attesting to the good selectivity and specificity of the developed sensor. The sensor has potential application in forensic investigations: its LOD and LOQ, intra and inter-day precision, accuracy, linearity ranges, selectivity, specificity, and sensitivity are better as compared to other chemically modified electrodes. Finally, the Density Functional Theory (DFT) method confirmed the oxidation-reduction mechanisms proposed in the literature. (AU)

• FAPESP's process: 16/01447-7 - Development of chemically modified electrodes (NDEs) with complexes of Schiff base for determination of cocaine: voltammetric studies and application of density functional theory (DFT)
• Grantee: Alex Soares Castro
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 16/23825-3 - Development of voltammetric sensors for determination of cocaine and delta-9-tetrahydrocannabinol in samples seized by the police
• Grantee: Marcelo Firmino de Oliveira
• Support Opportunities: Regular Research Grants