Comparative analysis of gamma-hydroxybutyrate and gamma-hydroxyvalerate using GC/MS and HPLC

This paper describes two analytical techniques used to separate and quantify gamma-hydroxybutyrate (GHB) and gamma-hydroxyvalerate (GHV). The first technique was a N,O-bis(trimethylsilyl)triflouro-acetimide-trimethylchlorosilane derivatization, followed by gas chromatography/mass spectrometry analysis using an HP-5 capillary column at a rate of 1.0 mL/min with a run time of 9.25 min. This technique was found to be sensitive (LOD 1 pg on column) and gave a low average error (5%) in a beverage study. When supplemented by a surrogate spike, the method yielded 97% analyte recovery from beverages. The second technique was high-performance liquid chromatography/UV (HPLC/UV) using a C-18 column with a (20:80% v/v) methanol:dibasic phosphoric buffer (10 mM, pH 3) at a rate of 1.00 mL/min with a run time of 7.5 min. UV detection occurred at 254 nm. This method was found to be less sensitive (LOD 0.05 microg on column) for direct analysis of aqueous samples. To remove interferences seen in the beverage study, a liquid-liquid extraction before HPLC analysis was tested. However, a decreased sensitivity (LOD 100 microg on column) and irreproducible peak profiles resulted.