This depends on your research questions. In any case you need to do a sample size calculation.

Depend to the objective(s). If this is for a method validation or preliminary study, you must have at least results from 20-30 samples for data analysis.

if you are performing the research including population or groups study, you need to do a sample size calculation.

It depends on the objectives of the study and the research question, Cochran's formula can be used.

Thank you for your response

Use Cochran formula

Cochram formula will guide you properly

Cochran formula will guide you.