Biomedical Engineering Reference
In-Depth Information
and 2). Hence, this potential was selected as the working potential for amperometric reg-
istration of AP activity [11,13].
The same cyclic voltammograms for iodine
product system
for amperometric detection of HRP-label activity were investigated. For amperometric
detection of HRP activity, the background and working voltammograms were obtained in
the presence of 1 mM potassium iodine (substrate-mediator for HRP) and different con-
centration of iodine in a sodium acetic-acid buffer solution pH 4.5 (Figure 22.3).
The range of reduction current of iodine, as HRP enzymatic reaction product, is
observed at potentials from
iodide as redox substrate
200 to
200 mV (shown in Figure 22.3 as black arrows for
cathodic curves 1 and 2). The
125 mV was selected as the working potential for amper-
ometric registration of HRP activity.
1
+300
2
3
4
0
300
600
400
200
0
200
400
600
Scaned potential (mV)
FIGURE 22.2
Cyclic volt
-naphthol (alkaline phosphatase (AP)
product): 1, 4 mM; 2, 2 mM; 3, 0.0 in 0.05 M sodium bicarbonate buffer solution (BcBS) with 1.0 mM
ampere diagrams obtained with two concentrations of
-naphthyl
(AP substrate) and 0.15 M NaCl; 4, 0.05 M BcBS with 0.15 M NaCl. Working electrode is graphite rod (5 mm diam-
eter), reference electrode is Ag/AgCl wire (1 mm diameter, 10 mm length), and counter electrode is carbon rod
(2 mm diameter, 10 mm length).
+300
1
2
3
0
300
0
200
400
600
600
400
200
Scaned potential (mV)
FIGURE 22.3
Cyclic volt
ampere diagrams obtained with different concentrations of iodine (HRP product): 1, 0.3 mM; 2, 0.5
mM; 3, 0.0 in 0.1 M AcBS with 1.0 mM KI and 0.15 M NaCl. Working electrode is graphite rod (5 mm diameter),
reference electrode is Ag/AgCl wire (1 mm diameter, 10 mm length), and counter electrode is carbon rod (2 mm
diameter, 10 mm length).
 
Search WWH ::




Custom Search