title: Determination of γ-hydroxybutyric acid in saliva by capillary electrophoresis coupled with contactless conductivity and indirect UV absorbance detectors.
abstract: The aim of the current study was to optimise and validate the methodology for determination of γ-hydroxybutyric acid (GHB) in saliva by CE combined with a contactless conductivity detector (C(4)D) and indirect UV absorbance detection (λ(ABS) = 210 nm). The optimized BGE, consisting of 8.5 mM maleic acid, 17 mM arginine, 255 μM cetyltrimethylammonium bromide (CTAB), and 15% acetonitrile, was evaluated for the separation of GHB in saliva within 6 min. The performance characteristics of the CE-C(4)D-indirect UV methodology was validated. The instrument detection and quantification limits were 0.49 and 1.6 mg/L for C(4)D, and 5.1 mg/L and 17.0 mg/L for indirect UV, respectively. The linearity was obtained over the range from 2.5 to 400 mg/L for C(4)D and from 12.5 to 400 mg/L for indirect UV. The interday precisions were within 2.3-5.7% and intraday precisions were within 1.6-9.0% for C(4)D as well as 2.1-9.3%, 5.6-10.1% for indirect UV in spiked saliva, respectively. The recoveries were within 87.2-104.4%. The matrix effects were +53.2% for small concentrations up to 25 mg/L for C(4)D and +23.6% for concentrations up to 75 for mg/L for indirect UV detection. No matrix effects were observed for higher concentration levels. In conclusion, CE-C4D-indirect UV can offer a rapid, accurate, sensitive, and definitive method for the determination of GHB abuse in saliva samples as a forensic screening tool.
authors.affiliation: Department of Chemistry, Tallinn University of Technology, Tallinn, Estonia.|NarTest AS, Tallinn, Estonia.
authors.forename: Jekaterina
authors.initials: J
authors.lastname: Mazina
authors.affiliation: Department of Chemistry, Tallinn University of Technology, Tallinn, Estonia.
authors.forename: Piret
authors.initials: P
authors.lastname: Saar-Reismaa
authors.affiliation: Department of Chemistry, Tallinn University of Technology, Tallinn, Estonia.
authors.forename: Maria
authors.initials: M
authors.lastname: Kulp
authors.affiliation: Department of Chemistry, Tallinn University of Technology, Tallinn, Estonia.
authors.forename: Mihkel
authors.initials: M
authors.lastname: Kaljurand
authors.affiliation: Department of Chemistry, Tallinn University of Technology, Tallinn, Estonia.
authors.forename: Merike
authors.initials: M
authors.lastname: Vaher
mesh_terms: D000328:Adult; D000368:Aged; D004553:Electric Conductivity; D019075:Electrophoresis, Capillary / Q000379:methods*; D005260:Female; D006801:Humans; D006885:Hydroxybutyrates / Q000032:analysis*; D057230:Limit of Detection; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012463:Saliva / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D006885:Hydroxybutyrates; C111420:4-hydroxybutyric acid
keywords: CE; Contactless conductivity detection; Indirect UV absorbance detection; Saliva; γ-Hydroxybutyric acid