A validated GC-MS procedure for fast, simple, and cost-effective quantification of glycols and GHB in human plasma and their identification in urine and plasma developed for emergency toxicology

Abstract

Methods developed for use in emergency toxicology have to be fast and simple. Additionally, such methods should be multi-analyte procedures because they allow monitoring of analytes of different drug classes in one single body sample. This is important because often only a limited amount of sample is available and the results have to be reported as fast as possible. Therefore, we describe the improvement of an existing method published by van Hee at al. The new method is fast and simple and designed for the simultaneous determination of ethylene glycol, 1,2-propylene glycol, lactic acid, glycolic acid, gamma-hydroxybutyric acid (GHB), diethylene glycol, triethylene glycol, and tetraethylene glycol in human plasma or urine. A 50-μL aliquot of sample was deproteinized and 20 μl of the diluted specimen were derivatized using bis-N,O-trimethylsilyl trifluoroacetamide and the catalyst dimethylformamide. After microwave-assisted derivatization, an aliquot was injected into the gas chromatograph and analyzed with electron ionization mass spectrometry in selective ion monitoring mode. All compounds are separated within 12 min and detected with a limit of quantification of 0.05 and 0.01 g/L for glycols and GHB, respectively. Calibration was linear from 0.05 to 1.0 g/L for glycols and 0.01 to 0.2 g/L for GHB. Validation criteria were shown to be in the required limits with exception of lactic acid. Average analysis time from starting sample preparation until quantitative plasma results of approximately 35 min was achieved. This turnaround time is considered most appropriate for emergency cases.