A highly sensitive non-enzymatic ascorbate sensor based on copper nanoparticles bound to multi walled carbon nanotubes and polyaniline composite

A novel, stable and highly sensitive non-enzymatic ascorbic acid sensor was developed using copper nanoparticles (CuNPs), carboxylated multi-walled carbon nanotubes (MWCNTs) and polyaniline (PANI) composite electrodeposited on gold electrode. The modified Au electrode was characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), cyclic voltammetry and impedance spectroscopy. The linear sweep voltammetry peak current showed a linear dependence on the ascorbic acid concentration and a linear calibration curve was obtained in the range, 5–600 μM of ascorbic acid with a correlation coefficient (r) of 0.998. The sensors response time was less than 2 s and detection limit was 1.0 μM (at signal/noise = 3). When tested with serum, fruits and vegetables, the sensor exhibited high electrocatalytic activity, fast response and good selectivity against common interfering species, suggesting its potential to be developed as a non-enzymatic ascorbic acid sensor.