ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

A rapid LC-MS/MS method for determination of urinary EtG and application to a cut-off limit study

Beril Anilanmert, Ali Acar Özdemir, Muhammet Aydin, Meral Akgül, and Salih Cengiz

Institute of Forensic Sciences, Faculty of Medicine, Istanbul University, 34303, Cerrahpasa / Istanbul, Turkey

E-mail: drberil@gmail.com

Abstract: Ethyl glucuronide (EtG) is a metabolite and a specific marker of alcohol consumption that can be detected days after the complete elimination of alcohol after drinking. A rapid, simple, and sensitive LC-ESI-MS/MS method for the determination of urinary ethyl glucuronide was developed and fully validated in accordance with analytical standards, using the C₁₈ column. The whole process including sample preparation and LC-MS/MS lasted 10 min. A comprehensive validation including HorRat, measurement uncertainty, system suitability and intermediate precision calculations among analysts, and a cut-off limit study was performed. The method was applied to real samples and a cutoff limit determination study. The LOD and LOQ (using the IUPAC and Eurachem methods) were determined as 104.21 ng mL⁻¹ and 165.00 ng mL⁻¹. A cut-off limit of ≈ 818 ng mg⁻¹ (normalised to creatinine) was found for urinary EtG. The results showed that the cut-off limits currently in use should be re-considered in further studies and standardised on a global scale. Normalisation to creatinine is important because of the risk of the dilution of urine intentionally or with a change of diet. The concentrations of real samples from subjects who had consumed alcohol were successfully predicted using this method, after zero HS-GC/MS results of urine alcohol concentration.

Keywords: ethyl glucuronide – LC-MS/MS – rapid determination in urine – validation – cut-off limit – alcohol metabolite

Full paper is available at www.springerlink.com.

DOI: 10.1515/chempap-2015-0173

Chemical Papers 69 (12) 1532–1540 (2015)