A novel high performance dual biosensor for the detection of aspartame in food samples
An improved high performance dual enzyme based biosensor has been
developed for the determination of aspartame in food samples. The
nanobiocomposite involves ammonium piperidine dithiocarbamate
(APDC) capped copper nanoparticles (CuNPs) loaded on multi walled
carbon nanotubes (MWCNTs) and assimilated with ?-cyclodextrin.
Finally, the dual enzyme system was immobilized onto the electrode
surface to construct CHT-LAAO/CuNPs-APDC-MWCNTs-?-CD/
GCE. Characterization was performed using Transmition electron
microscope (TEM), Thermogravimmetric analysis (TGA), X-ray
diffraction (XRD) and Fourier transition infrared spectroscopy (FTIR).
The biosensor showed optimum response within 5s at pH 7.5 and
35oC, when polarized at 0.25 V vs. Ag/AgCl. Furthermore, CHT and
LAAO were adsorbed tightly on the surface of the modified electrode
and shows enzyme activity to convert aspartame to its oxidized
product of keto ester and H2O2. There was a linear relationship
between biosensor response (mA) and aspartame concentration in
the range 0.001–2.0 mM. The sensitivity of the biosensor was 78.35 ?A
cm?2mM?1 with a detection limit of 0.005 mM (S/N=3). The long
term stability of the sensor in terms of 89.0% of the original response
on the third day was observed when conducted over a range of ten
runs for five days using the same coating. The biosensor was evaluated
and employed for the measurement of aspartame concentrations in
different commercially available food samples.