Development of silver/carbon screen-printed electrode for rapid determination of vitamin C from fruit juices

A silver/carbon screen-printed electrode (S/C-SPE) was fabricated using polymer-based conductive inks blended with in-house synthesized nanoparticles and investigated for its application in electrochemical analysis. Silver nanoparticles (∼59 nm) and carbon nanoparticles (∼76 nm) were synthesized having zeta potential (<±60 mV) and particle morphology were investigated for both the nanoparticles. These nanoparticles were blended with a thermoset epoxy resin to formulate different conductive inks viz. silver (Ag) ink, carbon (C) ink and silver/silver chloride (Ag/AgCl) ink. The formulated inks were characterized for their viscosity, which ranged from 1500 to 4500 cP making them ideal for screen printing. Post printing and thermal curing, the sensing area of the S/C-SPE was characterized for its elemental content by EDX, electrode thickness ranged from 0.3 to 0.8 μm and bulk resistance (ρ) (4.7-13.4 × 10−4 Ω-cm). The level of vitamin C was determined in different fruit juices at the S/C-SPE using a developed voltammetric method and compared with that of standard biochemical method. The vitamin C content of different juices ranged from 5 to 60 mg/100 ml. The analytical characteristics of the S/C SPE (linear range, reproducibility, stability, matrix effect, electrode saturation and response time) were investigated. The results obtained by the two methods were in good agreement.