Lanthanide Coordination Polymers of Tricarboxylic Acid Functionalized 1,2,3-triazole based Linker (Ln trz CPs) for Electrochemical Detection of Dopamine and Epinephrine

Abstract

Lanthanide coordination polymers [Ln(C18H12N3O7)2(OH)(H2O)]n (Ln = Nd, La, Ce) of tricarboxylic acid functionalized 1,2,3-triazole based linker were synthesized by solvothermal synthesis of Ln(NO3)3.6H2O and 5-((1-(4-carboxyphenyl)-1H-1,2,3-triazol-4-yl)methoxy)isophthalic acid in DMF. The formation of the coordination polymers and their chemical formula were proposed from the combination of different characterization techniques such as FTIR, ICP-OES, SEM-EDX, TGA, CHN-elemental, acid digestion HNMR spectroscopy and PXRD analysis. The materials were investigated for their electrochemical detection of epinephrine (EP) and dopamine (DA) at a scan rate of 50 mV/s in the voltage range of -0.4–0.8 V in 10 mM PBS. Nd trz CP/GCE exhibited highest activity for sensing of dopamine and epinephrine with limit of detection 1.8 µM and 1.84 µM and sensitivity of 5.18 µAµM−1cm− 2 and 9.9 µAµM−1cm− 2, respectively and performed well at pH 7. The Nd trz CP/GCE exhibited small charge transfer resistance (Rct) than La trz CP and Ce trz CP/GCE when measured using electrochemical impedance spectroscopy (EIS). Chronoamperometry study was conducted for testing the selectivity of the Nd trz CP modified electrode in the presence of 5 µM of ascorbic acid, uric acid, Ɣ-aminobutyric acid, cysteine, and glucose and the results showed that the catalyst is only responsive towards epinephrine and dopamine.