Novel Ce(OH)CO3/carbon nanotubes hybrid material towards a highly sensitive electrochemical dopamine determination in real urine samples

MUÑOZ, FERNANDO F.; COSCI, SANTIAGO; GONZALEZ JORGE, JOSÉ IVÁN; RINALDI, ANA L.; DABAS, PAULA; SOBRAL, SANTIAGO; CARBALLO, ROMINA; BONETTO M. CELINA

ELECTROCHIMICA ACTA

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2024 vol. 488

0013-4686

Ceriumhydroxycarbonate and multiwalled carbon nanotubes (Ce(OH)CO3/CNT),drop-casted onto a glassy carbon (GC) electrode and electrochemically treated  (tCe(OH)CO3/CNT) has been obtainedas a new hybrid material. tCe(OH)CO3/CNT was characterized throughSEM, FT-IR, UV–Vis, andelectrochemical techniques suchas cyclic voltammetry (CV) with differentredox couples as Fe2+/3+, Fe(CN)63-/4- or Ru(NH3)62+/3+ and electrochemical impedancespectroscopy (EIS) measurements with Fe(CN)63-/4- . The charge transfer resistance (RCT) valueof tCe(OH)CO3/CNT was up to two orders of magnitude lower than the RCTof bare GC electrodes and these results were confirmed by the effectiveheterogeneous electron transfer rate constant values (k◦eff, 2.4 10- 3 vs 7.0 10- 4,respectively). The calibration curve of DA exhibits a linear response withinthe range of 0.1 and 70 μmol L- 1 with acorrelation coefficient (R2) of 0.987 (n = 3) and alimit of detection of 0.003 μmol L-1.Inorganic and organic interferents do not alter significatively theselectivity. The electrochemical treatment of Ce(OH)CO3 and CNTgenerates a modified electrode which successfully combines the selectivity ofCe towards catechol with the high conductivity of CNT presenting an idealperformance for the electrochemical DA determination in 5 real urine samples(1.94 μmol L- 1 in a 1:20dilution) using differential pulse voltammetry (DPV) with an RSD < 6.1 %