Drugs are used everyday by people in many different ways for many different reasons. Drug testing has become a standard in pre-employment testing, because of the wide variety of drug use in today's society. Drugs tested for by a possible employer include Cocaine (crack), Amphetamines (crystal), Opiates (codeine, morphine, heroin), PCP (phencyclidine), and Marijuana. Gas chromatography/mass spectrometry is used to test hair and urine samples of possible drug abusers or job applicants, and it is the best method for the testing of drug use. Gas c ....