For any sample you prepare 5 different concentration and For each sample, record its reading from the UV device.

if you are not using microplate, time management would be difficult. in DPPH assay, incubation time is crucial so that we can compare the differences in the samples at exactly same time. Taking abs while taking lots of time for all the samples as well as positive control will hinder in the results and the justification would not be fair. I suggest you to use microplates. Otherwise manage your time while taking readings accordingly.

try to use Eppendorf's if you have available to work as a microplate. This way may be easier. Try to perform the assay with 6 concentrations for each sample and control. If Eppendorf's are also a concern, you can do a trial before: Just 3 or 2 concentrations of each sample to not waste time with lower concentrations if they can't inhibit the radical.

Thank you for your question

Yes, of course.

If you want, I can do it

Kind regards

You will have to use a plate reader to measure them all at once. Otherwise it will be hard to manage the time.

Yes you can take the absorbance of the samples and ascorbic acid first. Then from the obtained data you can calculate the % scavanging and IC50 value of the samples and standard

Rafina Naqiyya Qatrunnada Yes it is possible to do the experiment all at once including the sample and standard. Remember and manage time to maintain the dark incubation time accurately.

Look this paper

Article Antioxidant and antimicrobial activity of different plant pa...