[penhimdangyeu]

After we add Folin reagent into protein sample, we wait for the color development within 30 minutes. What wrong if the incubation time take longer than usual. I tested with 3 diferent incubation time and I recieved three different results after measuring colorimetrically.

[Arkcon]

Good work.  You've learned something important -- how you do things, including timing, has to be the same at all times you perform a procedure, if you want results you can rely on.  Now, some tasks for you -- how different were they?  Are they more different, over time, as they are with multiple runs with the same sample?  As an example of things to think about.

[penhimdangyeu]

I wonder whether any reaction occur after 30 minutes and more or not. I think something hapened inside the tubes but I dont know exactly what was going on. It may be due to the self-oxidation of some components inside or the colorimetric reaction continue to happen but out of control.