Stability of plasma gamma-hydroxybutyrate determined by gas chromatography-positive ion chemical ionization-mass spectrometry.
An effective method for the determination of gamma-hydroxybutyric acid (GHB) in human plasma is described that utilizes a simple liquid-liquid extraction procedure and gas chromatography-positive ion chemical ionization-mass spectrometry (GC-PCI-MS). The method has been used to study the stability of plasma GHB under several storage conditions. Following the extraction with acetonitrile, GHB and deuterated GHB (GHB-d(6)) were derivatized with N,O-bis[trimethylsilyl] trifluoroacetamide (BSFTA). After the separation on a capillary GC column, the derivatives were ionized with ammonia reagent gas and analyzed by MS. The lower limit of quantitation in 100 microL of plasma was 2.5 microg/mL, over a range from 2.5 to 250 microg/mL. The coefficients of variation did not exceed 3.9% and the mean measured concentrations did not deviate more than 8% from the target for both intra- and interassay precision and accuracy. Plasma GHB was found to be stable at -20 degrees C for up to 9 months, at room temperature for 48 h, and after 3 freeze/thaw cycles. It was also found to be stable in processed samples stored at room temperature for 5 days and for 15 days at -20 degrees C.
Chen
Meng
M
Center for Human Toxicology, Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, Utah 84112, USA. mc4@utah.edu
Andrenyak
David M
DM
Moody
David E
DE
Foltz
Rodger L
RL
D004355:Drug Stability; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D012680:Sensitivity and Specificity; D012978:Sodium Oxybate / Q000097:blood*; D013048:Specimen Handling; D015813:Substance Abuse Detection / Q000379:methods*
D012978:Sodium Oxybate