Step 16: Admire your product
Furthermore, this material is extremely pure. I analyzed it using gas chromatography/mass spectrometry, and found it to be >99% nepetalactone (see the second image below). In the chromatogram, nepetalactone is the giant peak around 12 min with a molecular weight of 166, and it's the only peak that is visible. For comparison, a sample of "catnip oil" that I purchased online was only about 80% nepetalactone (third picture).
If your sample has any amount of solid material mixed in with the liquid, most likely that is nepetalic acid. You may see that if you chose to omit the base wash from step 13. It's OK and isn't going to harm anything.