Development of Molecularly Imprinted Polymers for Forensic Applications

In some forensic disciplines various methods of extraction are used to perform analysis. Among these methods, solid phase extraction (SPE) and solid phase microextraction (SPME) are used in fields such as toxicology and explosives analysis. To enhance extraction efficiency in SPE and SPME, molecularly imprinted polymers (MIPs), which are designer polymers, can be more selective for the binding of an analyte or group of analytes that are similarly structured. Separation of analytes from complex mixtures is possible by utilizing these polymers. This may be especially useful in forensic applications where sample sizes may be small and composition may be complex. In this work, MIP solid phase microextraction fibers (MIP-SPME) were fabricated and caffeine was selectively sampled in the presence of theophylline and theobromine. Calibration studies were performed using the MIP-SPME to quantitate the concentration of caffeine in teas and coffees. MIP-SPME fibers were also prepared with 2,4-dinitrotoluene and deuterated 2,6-dinitrotoluene. Less selectivity was obtained for extraction of 2,4-DNT and 2,6-DNT in the presence of other DNT isomers. Fabricated blank polymers extracted analytes at the same response as templated polymers for both caffeine and DNT, despite expected results. MIP-SPE columns were also fabricated using deuterated 2,6-DNT to determine if changing the extraction procedure would increase extraction selectivity. Using different solvents in the extraction procedure changed the extraction performance efficiency of the MIPs due to the change in solvent polarity. All samples were analyzed using gas chromatography mass spectrometry