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Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: Biotech78 on February 06, 2020, 06:37:55 PM

Title: Electrochemistry question - HQ/H2O2 Chronoamperometry
Post by: Biotech78 on February 06, 2020, 06:37:55 PM
Hi all
I am trying to develop a sandwich immunosensor in which a peroxidase mimicking N.P is conjugated to secondary antibody will be used to catalyse the HQ/H2O2 reaction. I have consistently observed one weird thing which I have never been able to understand. Sometimes when I start the reaction with 1mM HQ alone on the SPE surface, the current seems unstable. Ideally what I expect is a slight decrease and stabilization within a few seconds (50-100 seconds) until I inject H2O2 at that point. Mos of the successful runs I observe the same (as picture attached) but in some cases the current actually starts to increase.
Also, is it OK if the current at the start is in negative as I have observed in some cases. Mostly it starts in the positive.
I would appreciate if someone could explain what's going on here, what's normal and if something is wrong how can I avoid it
Pardon my ignorance but my basic training is as a biologist and I am new to all this analytical and electrochemistry things