Nicotine presence can be detected in the blood for a short period only (about 48 hours) . However, its metabolite, cotinine, can be detected up to about three weeks from the last use and the cut-off detection levels is 200 ng/ml.
Q: What is the purpose of toner? Our skin is happiest at a pH of 5.5. Toner balances the pH of your skin. If you are acne prone the skin is too acidic. So finding a slightly alkaline toner can help balance the acidic nature. If the skin is dry, it is too alkaline, so finding a toner that has a lower pH can bring it to a happy balance of 5.5. Toning 1 minute after cleansing allows all the beneficial molecules to absorb into the skin as it is still wet.
A pH of 7 or less is considered acidic, which means all juice is acidic, but some is better-tolerated than others. For reference, citrus fruits such as lemon juice has a pH of 2.0 to 2.6, grapefruit a pH of 3 to 3.8 and orange juice a pH of 3.3 to 4.2, while apple juice has a pH of 3.4 to 4 and milk a pH of 6.3 to 6.6. Acidity in juice creates a sour taste, though the sourness is often offset by the natural sugar in juice.