Synthesis and characterization of tetra-ganciclovir cobalt (II) phthalocyanine for electroanalytical applications of AA/DA/UA

Abstract

Cobalt (II) phthalocyanine embedded with ganciclovir units has been synthesized by a novel method using tetracarboxylic phthalocyanine reported for the first time. The synthesized dark green colored complexes were characterized by electronic spectroscopy, elemental analysis, FT-IR, MASS and XRD. Thermal stability study reveals that the newly synthesized complex was stable up to 300 °C and XRD patterns showed amorphous nature of the complex. In the present work, the synthesized complex was characterized by cyclic voltammetry and shows the redox behavior corresponding to central metal (Co^+II/Co^+I) of the complex. Three biomolecules are well-separated by their oxidation peaks in simultaneous determination predicting the potentials for (-128, 335, and 723 mV) with highly increasing current. The low detection limit of AA, DA, and UA were 0.33, 0.03 and 0.10 μmol by CV method and good responses of amperometric and DPV technique. The modified tetra substituted CoTGPc/GCE exhibit an excellent electrocatalytic activity, stability, high sensitivity, good linearity, and selectivity without losing its catalytic activity and proves to be a versatile chemical sensor for commercial pharmaceutical samples, vitamin C tablets, and dopamine injections.

Keywords: Amperometry sensors; Analytical chemistry; Ascorbic acid; CoTGPc; Dopamine; Electrochemistry; Uric acid.

Scheme 1

Synthesis of tetra-carboxylic acid cobalt (II) phthalocyanine (CoTCPc).

Scheme 2

Synthesis of tetra-ganciclovir cobalt (II) phthalocyanine (CoTGPc).

Fig. 1

UV-Vis spectra of (a) tetra ganciclovir cobalt (II) phthalocyanine and (b) tetra carboxy cobalt (II) Phthalocyanine.

Fig. 2

FTIR spectra of (a) tetra ganciclovir cobalt (II) Phthalocyanine and (b) tetra carboxy cobalt (II) Phthalocyanine.

Fig. 3

TGA analysis of (a) tetra ganciclovir cobalt (II) Phthalocyanine and (b) tetra carboxy cobalt (II) Phthalocyanine.

Fig. 4

XRD spectra of tetra ganciclovir cobalt (II) Phthalocyanine.

Fig. 5

ESI-MS mass spectrum of tetra ganciclovir cobalt (II) phthalocyanine.

Fig. 6

CV plots of CoTGPc/GC electrode in PBS (pH=7) electrolyte system peaks at; (A) modified CoPc/GCE (B) 10 μM AA, (C) 15 μM DA and (D) 20 μM UA. Scan rate=100 mVs^-1.

Fig. 7

CVs plot of CoTGPc/GCE electrode in PBS (pH=7) electrolyte system at peaks: inset (a) bare GCE, (b) CoTGPc/GCE, (c) 10 μM of AA, (d)15 μM of DA and (e) 20 μM of UA (black dots peak). Scan rate=50 mVs^-1.

Fig. 8

CVs plot of CoTGPc/GCE in PBS (pH=7) electrolyte system peaks at; (A) Different scan rates of 10 μM AA, (B) Linear plot of positive peak current vs. different scan rates of AA/mV s^-1, (C) Different scan rate of 15 μM DA and (D) Linear plot of positive peak current vs. different scan rates of DA/mVs^-1.

Fig. 9

CV plots recorded of CoTGPc/GCE in PBS (pH=7) electrolyte system peaks at; (A) Different scan rate a-u (50-1000 mVs^-1) of AA, DA and UA. Linear plot of cathodic peak current vs. different scan rates of (B) AA, (C) DA and (D) UA/mVs^-1.

Fig. 10

CVs plot of CoTGPc/GCE in PBS (pH=7) electrolyte system peaks at; (A) Different concentrations 2-10 μM of AA at scan rate 50 mVs^-1, (B) Linear plot of peak current vs. different concentrations of AA/μM, (C) Different scan rate (10-100 mV/s) of AA and (D) Linear plot of positive peak current vs. different scan rates of AA.

Fig. 11

CVs plot of CoTGPc/GCE in PBS (pH=7) electrolyte system peaks at; (A) Different concentrations 2-10 μM of DA, (B) Linear plot of peak current vs. different concentrations of DA, (C) Different scan rate (10-100 mV/s) of DA and (D) Linear plot of peak current vs. different scan rates of DA.

Fig. 12

CVs plot of CoTGPc/GCE in PBS (pH=7) electrolyte system peaks at; (A) Different concentrations 2-10 μM of UA, (B) Linear plot of peak current vs. different concentrations of UA, (C) Different scan rate (10-120 mV/s) of UA and (D) Linear plot was positive peak current vs. different scan rates of UA.

Fig. 13

DPV plots recorded of CoTGPc/GCE in PBS (pH=7) electrolyte system peaks at; (A) Mixtures determination of 2―12×10^-6 M of AA, DA and UA. Linear plot of Ipc vs. different concentrations of (B) AA, (C) DA and (D) UA/μM. at scan rate= 50 mV/s.

Fig. 14

DPV plots recorded of CoTGPc/GCE in PBS (pH=7) electrolyte system peaks at; simultaneously determination of 2―12×10^-6 M, of (A) AA, (C) DA and (E) UA. Linear plot of Ipc vs. different concentration of (B) AA, (D) DA and (F) UA/μM. at scan rate= 50 mV/s.

Fig. 15

Amperometric individual response of CoTGPc/GCE in PBS (pH=7) electrolyte system peaks at; (A), (C), (E) various amounts (5-45 μL) of 10, 15, 20 μM for AA, DA UA; at fixed potential were -0.200 +0.400 and +0.700 V, and Linear plot of cathodic peak current (Ipc) vs. different amounts of (B) AA, (D) DA and (E) UA.

Fig. 16

Amperometric response of CoTGPc/GCE in (PBS) pH=7 in electrolyte system peaks at; (A) interference addition of different concentration (2, 5 and 10×10^-6 M) AA, DA and UA, (B) Linear plot of peak current vs. different concentrations of AA, DA and UA; at fixed potential +0.700 V.

Fig.17

Selectivity studies of interfering species like Nitrite (NO₂^-), Hydrogen Peroxide (H₂O₂) and Glucose (GOx) by during AA, DA and UA.