VladimirRogovsky

I've been working with this assay for 2 years. That's my experience: 1) Usually my ABTS stock solution is stable for approximately 2 weeks. I identify its degradation based on its color. If I cant obtain diluted working solution abs. 0.700 - then my stock solution is degraded. For example in first days I use 1 ml of stock solution and 99 ml of PBS to obtain abs. 0.7 in working solution, in next week I have to use 2 ml and 98 ml of PBS to obtain the same abs. 2) I usually prepare new diluted ABTS working solution for each experiment, because its abs. decreases significantly even during the experiment. 3) Usually SEM (standard error of the mean) in my ABTS experiments is more, than 0.05, so for me its no difference whether the range of abs. is 0.700±0.02 or 0.700±0.05. 4) I usually use 2.45 mM potassium persulfate and 7 mM ABTS in a ratio of 1:1, so I have no experience of mixing two times concentration of potassium persulfate and ABTS. 5) I have the same experience. Abs. of ABTS working solution is not stable and decreases even during experiment. I dont use 96-well plate, instead of this I use single plate. After 3-5 experimental tests I determine abs. of control ABTS working solution. Usually I incubate my probes for 2 minutes. When I analyse my results I compare each experimental result with its own control and determine the percent of abs. decreasing. Any way exposure to light of stock and working solution should be minimized. I'm glad if my experience can help you.