Amphetamines are controlled substances which are potent stimulants that induce fee領(lǐng)s of strength and energy while decreasing the need to sleep or eat. The majority of illegal amphetamine products are racemic; consequently, both isomers will appear in the biological fluids unchanged. In comparison the break-down products formed by the metabolism of most pharmaceutical drugs show the appearance of pure amphetamine enantiomers. Circular dichroism is a form of light absorption spectroscopy that measures the difference in absorbance of right- and leftcircularly polarized light (rather than the commonly used absorbance of isotropic light) by a substance. Since different enantiomers absorb different portions of the light, it provides and excellent means for enantiomer detection. In this application CD will be used to study the isomers of amphetamine and methamphetamine. JASCO圓二色光譜儀CD J-1500