Determination of gamma-hydroxybutyric acid (GHB) in plasma and urine by headspace solid-phase microextraction and gas chromatography/positive ion chemical ionization mass spectrometry.
A new method for the qualitative and quantitative analysis of gamma-hydroxybutyric acid (GHB) in plasma and urine samples is described. It involves the conversion of GHB to gamma-butyrolactone (GBL), its subsequent headspace solid-phase microextraction (SPME), and detection by gas chromatography/positive ion chemical ionization mass spectrometry (GC/PICI-MS), using D(6)-GBL as internal standard. The assay is linear over a plasma GHB range of 1-100 microg/mL (n = 5, r = 0.999) and a urine GHB range of 5-150 microg/mL (n = 5, r = 0. 998). Relative intra- and inter-assay standard deviations, determined for plasma and urine samples at 5 and 50 microg/mL, are all below 5%. The method is simple, specific and reasonably fast. It may be applied for clinical and forensic toxicology as well as for purposes of therapeutic drug monitoring.
Frison
G
G
Forensic Toxicology and Antidoping, University Hospital of Padova, Via Falloppio 50, I-35121 Padova, Italy.
Tedeschi
L
L
Maietti
S
S
Ferrara
S D
SD
D015107:4-Butyrolactone / Q000378:metabolism; D002138:Calibration; D016903:Drug Monitoring / Q000379:methods; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006885:Hydroxybutyrates / Q000097:blood* / Q000378:metabolism / Q000627:therapeutic use / Q000652:urine*; D012015:Reference Standards; D012680:Sensitivity and Specificity; D013696:Temperature
D006885:Hydroxybutyrates; C111420:4-hydroxybutyric acid; D015107:4-Butyrolactone