How to say you did two things, but separately?

Question

When describing an experiment (inside a thesis paper), I want to explain that we took a sample and did two things to it, but not together, rather as two separate experiments.

One way to write it is :

We took the sample and either did X to it, or did Y to it.

Another way is:

We took the sample and did X to it, and separately did Y to it.

Frankly I'm not happy with either forms. What's a good way to write this?

Answer 1

Sample taking is pretty much assumed, so no need to emphasize that at the start of your sentence. How about something like: "Samples were subjected to Kjeldahl analysis or Multiplex polymerase chain reaction followed by capillary electrophoresis"?

Answer 2

We did X to the sample in one experiment and Y to it in another.

Answer 3

It is unclear from the example sentences how the sample was treated. One might more clearly say something like the following:

We did X to the sample, and then did Y to that result.
We did X to part of the sample, and Y to another part.
Separate portions of a sample were given treatment X or treatment Y.

You could prefix "After taking the sample," or "A sample was taken and" to the above if for some reason you wish to emphasize that a sample was taken, but otherwise could leave the sample-taking as an implied fact.