Amphetamines are controlled substances whichare potent stimulants that induce feelings ofstrength and energy while decreasing the need tosleep or eat. The majority of illegal amphetamineproducts are racemic consequently, both isomerswill appear in the biological fluids unchanged. Incomparison the break-down products formed bythe metabolism of most pharmaceutical drugsshow the appearance of pure amphetamineenantiomers. Circular dichroism is a form of lightabsorption spectroscopy that measures thedifference in absorbance of right- and leftcircularlypolarized light (rather than the commonlyused absorbance of isotropic light) by a substance.Since different enantiomers absorb differentportions of the light, it provides and excellentmeans for enantiomer detection. In thisapplication CD will be used to study the isomers ofamphetamine and methamphetamine.
AbstractThis application note describes two approaches for achieving robust, multiresidue pesticide analysis in 10 minutes by GC/MS/MS, while maintaining sufficient chromatographic resolution for the analysis of over 200 pesticides in spinach a challenging high chlorophyll, fresh matrix. First, the conventional 15 × 15 m (0.25 mm × 0.25 μm) midcolumn backflush configuration was used with an accelerated oven ramp, yielding an analysis time of 10 minutes. Second, a minibore 10 × 10 m (0.18 mm × 0.18 μm) midcolumn backflush configuration was used,enabling a fast 10-minute analysis time. The latter method was precisely scaled using the Agilent GC method translation technique. It was shown that midcolumn backflushing enabled method robustness and extended maintenance-free operation of the system by minimizing column trimming and source cleaning. Resultsdemonstrate that the Agilent 7000E and 7010C triple quadrupole GC/MS systems delivered excellent linearity over a concentration range of 0.1 to 1,000 parts perbillion (ppb). Method robustness was shown with 700 consecutive injections of a spinach extract, spiked with pesticides at 20 ppb, that spanned over 175 hours ofcontinuous running of the GC/TQ.