Determination of gamma-hydroxybutyric acid in biological fluids by using capillary electrophoresis with indirect detection.
gamma-Hydroxybutyric acid (GHB) is a central nervous system (CNS) depressant and hypnotic which, in recent times, has shown an increasing abuse either as recreational drug (due to its euphoric effects and ability to reduce inhibitions) or as doping agent (enhancer of muscle growth). Analogues of GHB, namely gamma-butyrolactone (GBL) and 1,4-butanediol (1,4-BD), share its biological activity and are rapidly converted in vivo into GHB. At present, GHB and analogues are placed in the Schedules of Controlled Substances. Numerous intoxications in GHB abusers have been reported with depressive effects, seizures, coma and possibly death. The purpose of the present work was the development of a rapid analytical method based on capillary zone electrophoresis for the direct determination of GHB in human urine and serum at potentially toxic concentrations. Analytical conditions were as follows. Capillary: length 40 cm (to detector), 75 microm i.d.; buffer: 5.0 mM Na(2)HPO(4), 15 mM sodium barbital adjusted to pH 12 with 1.0 M NaOH; voltage: 25 kV at 23 degrees C; indirect UV detection at 214 nm; injection by application of 0.5 psi for 5 s. alpha-Hydroxyisobutyric acid was used as internal standard (IS). Sample pretreatment was limited to 1:8 dilution. Under these conditions, the sensitivity was approximately 3.0 microg/ml (signal-to-noise ratio >3). Calibration curves prepared in water, urine and serum were linear over concentration ranges 25-500 microg/ml with R(2)>/=0.998. Analytical precision was fairly good with R.S.D.<0.60% (including intraday and day-to-day tests). Quantitative precision in both intraday and day-to-day experiments was also very satisfactory with R.S.D.</=4.0%. No interferences were found neither from the most common "drugs of abuse" nor from endogenous compounds. In conclusion, capillary electrophoresis can offer a rapid, precise and accurate method for GHB determination of biological fluids, which could be important for screening purposes in clinical and forensic toxicology.
Bortolotti
Federica
F
Department of Medicine and Public Health, Unit of Forensic Medicine, University of Verona, Policlinico G.B. Rossi, Verona 37134, Italy. febo@virgilio.it
De Paoli
Giorgia
G
Gottardo
Rossella
R
Trattene
Maristella
M
Tagliaro
Franco
F
D002138:Calibration; D004300:Doping in Sports; D062787:Drug Overdose / Q000175:diagnosis; D019075:Electrophoresis, Capillary; D004632:Emergency Medical Services; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006993:Hypnotics and Sedatives / Q000032:analysis* / Q000097:blood / Q000652:urine; D007202:Indicators and Reagents; D012015:Reference Standards; D012978:Sodium Oxybate / Q000032:analysis* / Q000097:blood / Q000652:urine; D013056:Spectrophotometry, Ultraviolet; D019966:Substance-Related Disorders / Q000097:blood / Q000652:urine
D006993:Hypnotics and Sedatives; D007202:Indicators and Reagents; D012978:Sodium Oxybate