Detection of gamma-hydroxybutyrate in hair: Validation of GC-MS and LC-MS/MS methods and application to a real case

trova@unifi(opens in a new window)|View at Publisher| Export | Download | Add to List | More... Journal of Pharmaceutical and Biomedical Analysis Volume 70, November 2012, Pages 518-522 Detection of gamma-hydroxybutyrate in hair: Validation of GC-MS and LC-MS/MS methods and application to a real case (Article) Bertol, E.a , Argo, A.b, Procaccianti, P.b, Vaiano, F.a, Di Milia, M.G.a, Furlanetto, S.c, Mari, F.a a Forensic Toxicology Division, Institute of Legal Medicine, University of Florence, Italy b Department of Biopathology Biotechnology and Legal Medicine, University of Palermo, Italy c Department of Pharmaceutical Sciences, University of Florence, Italy View additional affiliations View references (17) Abstract A gas chromatography-mass spectrometry (GC-MS) and a liquid chromatography tandem mass spectrometry (LC-MS/MS) method were validated for quantifying endogenous and exogenous hair concentrations of gamma-hydroxybutyrate (GHB). The GC-MS method is based on overnight extraction of 25. mg hair in NaOH at 56°C, liquid/liquid extraction in ethylacetate and trimethylsylil derivatization; analysis is by electron ionization and single ion monitoring of three ions. The LC-MS/MS method entails a rapid digestion of 25. mg hair with NaOH at 75°C for 40. min, liquid/liquid extraction in ethylacetate and reconstitution of the extract in the LC mobile phase; negative ion electrospray ionization and multiple reaction monitoring (MRM) analysis are employed for the LC-MS/MS detection. In both cases, GHB-d6 is used as an internal standard. The endogenous amount in " blank" hair are estimated by the standard addition method. Limits of detection are 0.4 and 0.5. ng/mg for GC-MS and LC-MS/MS respectively, while the limit of quantification (LOQ) is 0.6. ng/mg for both methods; the GC-MS method proved to be linear in the range 1-50. ng/mg whereas linearity was demonstrated from 0.6 to 50. ng/mg for the LC-MS/MS; imprecision and inaccuracy were always lower than 23% for quality controls samples. The two methods were applied to a real case of a man addicted to GHB; the drug concentration in segments from 17. cm hair strand well correlated with self-reported use of GHB in different periods of his life