Generally speaking it takes 12 hours, for some few hours more and others less.However, the chemical dependency of nicotine is far more tricky. If you are trying to quit I would recommend staying clear of all stimulants including caffeine, alcohol...ect. Stimulants only fuel your brains craving for the next fix of nicotine. It takes 3-4 days for your body to break free of this craving...after that you have 30 days to break the oral fixation...and then its just a monkey on your back that gets easier for you to tell to shut-up. Good Luck.
It takes 72 hours for all nicotine to leave your system whether you smoke or use a form of NRT (nicotine replacement therapy). Check out whyquit.com....it tells it all
to be honest im not sure , but black natural liquarice helps ,