Total Vaporization Solid-Phase Microextraction (TV-SPME) relies on the same mechanism as standard headspace SPME but completely vaporizes a liquid sample as analytes are adsorbed onto the fiber coating [1,2]. This allows for partitioning of the analyte between only the vapor and the coating of the fiber. A marked increase in sensitivity has been previously demonstrated for nicotine and cotinine utilizing a TV-SPME method [1]. With this approach, more of the sample is adsorbed onto the fiber and relatively large sample volumes (e.g., up to 100 µl) may be used. This method also helps to eliminate matrix effects due to this being a two-phase system

Gas chromatography-mass spectrometry (GC-MS) is a "workhorse" in the analysis of controlled substances in forensic laboratories. However, many drugs are not amenable to GC-MS due to thermal instability, non-ideal interactions in the column, or both. To improve the suitability of a molecule for analysis by GC-MS, derivatization can be employed. Derivatization replaces a labile hydrogen in the analyte molecule with a more stable functional group. In this paper, three different derivatization agents were tested for effectiveness with two classes of drugs: primary amines (i.e., amphetamine and 2C-I) and zwitterions (i.e., gabapentin, lorazepam, vigabatrin, pregabalin, and clorazepate). Trifluoroacetic anhydride (TFAA) was used as an acylating agent and N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) was used as a silylating agent. Dimethylformamide-dimethyl acetal (DMF-DMA), which has not been previously used for derivatization of drugs, was used as an alkylating agent. DMF-DMA was found to form dimethylaminomethylene derivatives with several primary amines and zwitterions. Amphetamine, 2C-I, gabapentin, and lorazepam were all detected in their underivatized form but generally suffered from peak asymmetry and band broadening. Derivatization resulted in drastic improvements in their chromatographic behavior. Vigabatrin, clorazepate and pregabalin were not detectable in their underivatized form. However, the trimethylsilyl (TMS) derivative of clorazepate was readily detected by GC-MS, as were the TMS and trifluoroacetyl (TFA) derivatives of vigabatrin. Derivatization of pregabalin was not successful, resulting in multiple chromatographic peaks with each derivatization agent. The mass spectra of several derivatives were not found in commercially available mass spectral databases. Hence, those spectra are reported here with interpretation of their fragmentation.

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