Beginning of Essay
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 ( ....

Middle of Essay
.... gas chromatograph offers rapid and very high-resolution separations of a very wide range of compounds, with the only restriction that the analyzed substance needs to have sufficient volatility. The theory behind the mass spectrometer is to use the difference in mass-to-charge ratio (m/e) of ionized atoms or molecules to separate them from each other. Mass spectrometry is therefore useful for quantitation of atoms or molecules and also for determining chemical and structural information about molecules. Molecules have distinctive fragmentation patterns that provide structural information to identify structural components. The combination of the gas ch ....