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 toner should be left for only 20 minutes to 30 minutes maximum on the hair. Fir exact time duration, check the directions at the package of the particular brand of the toner that you are using . If toner is left for a long time, it turns the hair gray .