I want to determine the glucose concentration of my samples using the Biosensor. However, my samples contain glucose oxidase (GOD) in order to remove hydrogen peroxide from my samples.
The principle of the biosensor is that the glucose in the sample generates hydrogen peroxide by glucose oxidase in the enzyme electrode. Then, the generated hydrogen peroxide is oxidized by the platinum anode. The glucose concentration is then determined by the change of the currect value according to this oxidation.
Because my samples contain glucose oxidase, the glucose concentration decreases.
I determined the glucose concentration of a known sample, having a concentration of 1.9 g/L. However, when GOD is added to my sample, the concentration decreases to 1.75 g/L .
Therefore, I want to remove glucose oxidase prior to using the Biosensor. How can I do this?
Filtering the sample using a size exclusion column (NAP 25 for example) could easily separate glucose from GOD by fractionation. This, however, will dilute the sample and the peroxide may react with the column. Denaturing agents (urea, guanidine) or specific metal salts could inhibit GOD, but those may be electroactive.
Also, keep in mind that GOD does not remove hydrogen peroxide, but in fact produces it! ("...glucose oxidase (GOD) in order to remove hydrogen peroxide from my samples"). If needed, peroxide removal could be performed with the HRP enzyme.
Best regards,
Roy
Roy Cohen Thank you very much for the reply Sir Cohen.
My mistake, I have glucose oxidase in my samples in order to produce hydroygen peroxide and in order to remove hydrogen peroxide, I added catalase since the biosensor uses hydrogen peroxide to determine the glucose concentration.
Because my samples contains both glucose oxidase and catalase, the concentration of glucose read by the biosensor deviates and decreases.
I thought of heating my samples to denature the enzymes present in my samples. However, my samples might evaporate. So I am still not sure how to go about this. Thank you very much your suggestions, Sir Cohen. I will keep this is mind.
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