Enhancement of Drug Detection and Identification by Use of Various Derivatizing Reagents on GC-FTIR Analysis.
FEDERAL AVIATION ADMINISTRATION WASHINGTON DC OFFICE OF AVIATION MEDICINE
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Phenylpropanolamine PPA is a relatively common non-prescription sympathomimetic amine. As such, it is frequently detected during forensic analysis. The presence of phenylpropanolamine can be confirmed by using Gas Chromatograph-Fourier Transform Infrared GC-FTIR spectrophotometry. One constraint of the GC-FTIR is the quantity of material required to obtain a suitable IR spectrum. If a drug is a relatively weak infrared absorber, several micrograms may be required in order to obtain a clear, reliable spectrum. While this amount of material may be readily available for some types of analysis, it can easily exceed the quantity of material available in the forensic toxicology setting. One method that can be used to increase a drugs infrared absorption is to derivatize the drug with a polyfluorinated acid anhydride. Since carbonyl and carbon-fluorine bonds are strong infrared absorbers, molecules that possess such bonds have a heightened sensitivity to GC-FTIR analysis. Polyfluorinated acid anhydrides are capable of adding both carbonyl and carbon-fluorine bonds to drugs that possess either a hydroxyl, primary or secondary amine, or primary or secondary amide functional groups. Several derivatizing reagents were used and the extent to which they enhanced the identification of phenylpropanolamine were compared. Of the reagents studied, heptafluorobutyric acid anhydride HFAA produced the greatest increase in the phenylpropanolamines sensitivity to GC- FTIR identification. Prior to derivatization, 1.8 micrograms of phenylpropanolamine was required for identification on the GC-FTIR, while only 0.032 micrograms of phenylpropanolamine was required after derivatization with HFAA. GC-FTIR, Drugs, Phenylpropanolamine.
- Organic Chemistry
- Physical Chemistry