title: Stability of ethyl glucuronide in hair reference materials after accelerated aging.
abstract: Two different hair reference materials, one produced from authentic hair displaying an ethyl glucuronide (EtG) content of about 25 pg/mg and one obtained by fortification of blank hair to an EtG level of 85 pg/mg were submitted to accelerated aging between 4 °C and 60 °C for periods between one and 24 months. Subsequently, the EtG content was determined in the aged samples and untreated reference samples stored at -22 °C under repeatability conditions following the so-called isochronous approach. The EtG content remained stable even at 40 °C for 24 months and at 60 °C over six months. This is in contrast to many organic analytes contained in trace concentrations in diverse matrices. A slight but significant increase of the recovered EtG in case of authentic hair samples having been exposed for 24 months between 4 °C and 60 °C may be due to a temperature-driven process that allows increased recoveries of the physiologically embedded EtG.
authors.affiliation: Federal Institute for Materials Research and Testing (BAM), Berlin, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Ammann
authors.affiliation: Federal Institute for Materials Research and Testing (BAM), Berlin, Germany. Electronic address: roland.becker@bam.de.
authors.forename: R
authors.initials: R
authors.lastname: Becker
authors.affiliation: Federal Institute for Materials Research and Testing (BAM), Berlin, Germany.
authors.forename: I
authors.initials: I
authors.lastname: Nehls
mesh_terms: D015415:Biomarkers / Q000032:analysis; D002853:Chromatography, Liquid; D004355:Drug Stability; D053593:Forensic Toxicology; D005965:Glucuronates / Q000032:analysis*; D006197:Hair / Q000737:chemistry*; D006801:Humans; D013058:Mass Spectrometry; D013048:Specimen Handling; D013997:Time Factors
chemical_list: D015415:Biomarkers; D005965:Glucuronates; C093924:ethyl glucuronide
keywords: Alcohol marker; Fortification; HPLC–MS/MS; Long term stability; Micropulverization