A rapid, precise, low cost, selective and sensitive paper-based
electrochemical device for the determination of H2O2 in milk is
described here. Commercially available varnish and a simple hand
drawing method were used to develop the hydrophobic pattern to
generate a hydrophilic detection zone on the filter paper. The
electrode system was fabricated on the detection zone in order to
detect H2O2 electrochemically. A commercially available graphite
pencil and conductive silver ink were used to fabricate the counter
electrode and pseudo-reference electrode, respectively. A paste of
Prussian blue (PB) modified graphite, unmodified graphite and
phenol-formaldehyde polymer were used to fabricate a PB modified
graphite working electrode on paper. This modified electrode
showed electrocatalytic activity towards the reduction of H2O2 and
it was successfully used for the chronoamperometric detection of
H2O2 at 0 V vs Ag reference electrode in 0.1 mol l
-1 phosphate
buffer, buffered at pH 6.0 in 0.1 mol l
-1 KCl. Under optimum
conditions, the calibration curve for the H2O2 determination was
linear from 5 to 50 mmol l
-1 with a detection limit (LoD = 𝑥̅+ 3SD)
of 4.0 mmol l
-1
. In addition, the PB modified graphite electrode
showed selectivity for H2O2 detection in the presence of ascorbic
acid, sucrose and citric acid.
Abstract
A rapid, precise, low cost, selective and sensitive paper-based
electrochemical device for the determination of H2O2 in milk is
described here. Commercially available varnish and a simple hand
drawing method were used to develop the hydrophobic pattern to
generate a hydrophilic detection zone on the filter paper. The
electrode system was fabricated on the detection zone in order to
detect H2O2 electrochemically. A commercially available graphite
pencil and conductive silver ink were used to fabricate the counter
electrode and pseudo-reference electrode, respectively. A paste of
Prussian blue (PB) modified graphite, unmodified graphite and
phenol-formaldehyde polymer were used to fabricate a PB modified
graphite working electrode on paper. This modified electrode
showed electrocatalytic activity towards the reduction of H2O2 and
it was successfully used for the chronoamperometric detection of
H2O2 at 0 V vs Ag reference electrode in 0.1 mol l
-1 phosphate
buffer, buffered at pH 6.0 in 0.1 mol l
-1 KCl. Under optimum
conditions, the calibration curve for the H2O2 determination was
linear from 5 to 50 mmol l
-1 with a detection limit (LoD = 𝑥̅+ 3SD)
of 4.0 mmol l
-1
. In addition, the PB modified graphite electrode
showed selectivity for H2O2 detection in the presence of ascorbic
acid, sucrose and citric acid.
