I am not sure what kind of situation you are talking about right now.
I assume two cases as below :
1) Sample received from supplier
- Please be informed that the sample you sent dated ( xx / xx / xx ) is received and confirmed ,we will send to customer for approval.We will keep you posted.
Will contact you once I need anything else / I have problems.
2)Once the sample is approved by customer ,we need to inform supplier the item is approved .
- Pleased to inform you that your sample dated ( xx / xx / xx ) is approved today.Please go ahead to proceed any pending orders.Thanks for your effort.
both are ok, depending on what context you're using them. 'sample confirmation' is a noun phrase, so you can use it as in "The sample confirmation has been performed in XXX factory."
In my view, I think 'sample confirmed' is more widely used. You'd probably use it as in "The sample confirmed has been sent to you for reference."
btw, I'm not very sure what kind of samples you're referring to. i think the verb for 確認 can be other than 'confirm' , depending on what sample you're talking about.