Extractionless GC/MS analysis of gamma-hydroxybutyrate and gamma-butyrolactone with trifluoroacetic anhydride and heptafluoro-1-butanol from aqueous samples.

gamma-Hydroxybutyrate (GHB) is a DEA Schedule I drug of abuse commonly spiked into beverages to incapacitate victims of sexual assault. GHB is a challenging drug for analysis by GC/MS because of its small size, charged nature, low volatility, and intramolecular esterification leading to gamma-butyrolactone (GBL). In this work an extractionless technique has been developed that allows for the use of an aqueous sample for direct derivatization. The technique uses a solution of trifluoroacetic anhydride (TFAA) and 2,2,3,3,4,4,4-heptafluoro-1-butanol (HFB) to derivatize the active hydrogens of GHB. The conversion of GBL into GHB can be forced under alkaline conditions by diluting the sample in 10 mM borate buffer, pH 12. GBL found in beverages intended for human consumption is treated as a Schedule I control substance analogue. Spikes of the two compounds into several beverage matrices gave quantitative recovery of GHB by GC/MS. The derivatization produces higher molecular mass products whose fragmentation pattern provides multiple peaks for confirmation and quantification. The concentration of GBL can also be indirectly determined by the method developed. Therefore, this extractionless technique is rapid, sensitive, and selective for the confirmation of the presence of GHB and GBL in commercial beverages.