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.

Contactless conductivity detection for analytical techniques— Developments from 2014 to 2016

“…Pretreatment of human body fluids prior to CE‐C 4 D analyses was performed by standard techniques, such as precipitation and liquid‐liquid extraction , moreover, the application of novel microextraction techniques was also reported. Determination of formic acid in whole blood and serum samples after methanol intoxication , three amphetamines in spiked plasma samples , plasma concentrations of branched chain amino acids in secretion studies and tamoxifen and its metabolites in plasma samples of patients with breast cancer undergoing tamoxifen treatment were presented.…”

“…Moreover, as the content of proteinaceous matrix components is relatively low, pretreatment of saliva samples is rather simple and usually requires dilution and filtration/centrifugation only. Various major as well as minor analytes were determined in saliva samples demonstrating the potential of CE‐C 4 D in analysis of salivary inorganic anions , γ‐hydroxybutyric acid , inorganic cations/anions and organic anions and polyamines . DOI was applied for simultaneous determination of cations and anions to reduce the total analysis time and EME (see Section ) was necessary to preconcentrate salivary polyamines to levels detectable by C 4 D .…”

A five-electrode capacitively coupled contactless conductivity detector with a low limit of detection

“…[6][7][8][9][10][11][12] In addition, C 4 D has the advantages of miniaturization and being nondestructive to samples. Thus it has been widely applied in the elds of environment, 13,14 food, 15,16 medicine [17][18][19] and others.…”