I emailed Chris at My Freedom Smokes, here is his response.
You have to shake the bottle before you open and use it. Nicotine smells like pesticide. It is very unpleasant when it is in it’s pure state. We use 999mg (free-base) nicotine to mix our unflavored and when mixed with VG, it separates and the nicotine rises to the top of the bottle. What you are smelling is pure nicotine. I can assure you there is nothing wrong with what we sent you.
You have to shake the bottle before you open and use it. Nicotine smells like pesticide. It is very unpleasant when it is in it’s pure state. We use 999mg (free-base) nicotine to mix our unflavored and when mixed with VG, it separates and the nicotine rises to the top of the bottle. What you are smelling is pure nicotine. I can assure you there is nothing wrong with what we sent you.