| dc.description.abstract | Paper-based electroanalytical devices are more
attractive than any other analytical techniques for
determining the caffeine (CAF) content in different
applications to assess the quality of food and pharmaceuticals
due to the simplicity, portability, sensitivity, stability and low cost nature of the devices. This research employs a paper base
and a commercially available polyurethane varnish to
develop the hydrophobic pattern to generate the hydrophilic
detection zone in which the sample is spiked. The electrode
system having three electrodes, was fabricated on the
detection zone for the electrochemical detection of caffeine
using cyclic voltammetry (CV). The working electrode was
modified with anthraquinone and showed electrocatalytic
activity towards the oxidation reaction of caffeine.
Throughout the research, unmodified carbon paste electrodes
(UMCPEs) and silver plates served as counter and pseudo reference electrodes respectively. The pH, scan rate, and
modifier concentration were optimized to improve the
analytical performance. Under optimum conditions, the
calibration plot that was obtained between peak current and
the caffeine concentration showed a good correlation with a
correlation coefficient as high as 0.99, over the concentration
range from 0.1 mM to 1.0 mM, having a detection limit (LoD),
quantification limit (LoQ), and sensitivity (S) of 40 µM, 0.4
mM and 5.0 ×10-6 A mM-1
respectively. The electrochemical
analysis demonstrated the applicability and reliability of this
method, since the calculated precision, accuracy, detection,
and quantification limits (LoD and LoQ) fall within the
acceptable range for monitoring caffeine levels in various
samples. The low-cost nature, high sensitivity, and good
linearity further support it’s potential as an effective
analytical method for caffeine determination | en_US |
