title: 1H NMR analysis of GHB and GBL: further findings on the interconversion and a preliminary report on the analysis of GHB in serum and urine.
abstract: A 1H nuclear magnetic resonance (1H NMR) method for the determination of gamma-hydroxybutyric acid (GHB) and gamma-hydroxybutyrolactone (GBL) in human serum and urine using spiked samples has been developed. The method gives linear responses (correlation coefficients of 0.99 or greater) over the concentration range 0.01 mg/mL to 4.0 mg/mL in urine and 0.3 mg/mL to 2.0 mg/mL in serum. No sample pretreatment is required. Studies of the chemical interconversion of GBL and GHB showed hydrolysis of GBL to be rapid at pH 11.54, slower and less complete (30% hydrolysis) at pH 2.54 and slowest at pH 7.0, reaching 30% hydrolysis in about 40 days. No esterification of GHB was observed at any pH.
authors.affiliation: Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA.
authors.forename: Anthony G
authors.initials: AG
authors.lastname: Del Signore
authors.forename: Michael
authors.initials: M
authors.lastname: McGregor
authors.forename: Bongsup P
authors.initials: BP
authors.lastname: Cho
mesh_terms: D015107:4-Butyrolactone / Q000097:blood* / Q000652:urine*; D002138:Calibration; D005554:Forensic Medicine / Q000379:methods; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D006885:Hydroxybutyrates / Q000097:blood* / Q000652:urine*; D009682:Magnetic Resonance Spectroscopy; D012680:Sensitivity and Specificity; D012997:Solvents / Q000032:analysis*; D013048:Specimen Handling
chemical_list: D006885:Hydroxybutyrates; D012997:Solvents; C111420:4-hydroxybutyric acid; D015107:4-Butyrolactone