1. Validation of a headspace solid-phase microextraction–GC–MS/MS for the determination of ethyl glucuronide in hair according to forensic guidelines 
Ronald Agius, Thomas Nadulski, Hans-Gerhard Kahl, Johannes Schräder, Bertin Dufaux, Michel Yegles, Fritz Pragst 
Forensic Science International 
Volume 196, Issue 1, Pages 3-9 (March 2010)
DOI: /j.forsciint
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2. Fig. 1
Negative chemical ion mass spectra of (a) EtG and (b) EtG-d5 after derivatization with heptafluorobutyric acid anhydride in full scan mode.
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3. Fig. 2 EtG, EtG-PFPA and EtG-HFBA derivatives [26].
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4. Fig. 3
Optimization of the SPME extraction time and the SPME extraction temperature for the determination of EtG in hair using HS-SPME and NCI-GC–MS; calculated by multivariate analysis (central composite design; CCD) [26]. (a) Temperature vs. extraction time 2D and (b) temperature vs. extraction time 3D.
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5. Fig. 4
(a) MRM chromatogram for a blank hair sample and (b) MRM chromatogram m/z 596→427 and m/z 596→288 for EtG in a spiked control at the cut-off concentration of 8pg/mg hair (peak to the right) with a signal to noise ratio of 447; MRM chromatogram m/z 601→432 and 601→288 for EtG-D5, used as an internal standard at 50pg/mg hair (peak to the left).
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6. Fig. 5
MRM chromatogram m/z 596→427 and m/z 596→288 for EtG in a real hair sample at the LLOQ level (2.8pg/mg hair) with a signal to noise ratio of 62.
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7. Fig. 6
Internal QC for EtG in hair for 20 separate days for spiked controls at (a) 8pg/mg, (b) 25pg/mg, (c) 40pg/mg and (d) 120pg/mg hair showing the calculated maximal permissible values using the rms deviations of measurement; Xo, target value; ULEL, upper laboratory error limits and LLEL, lower laboratory error limits.
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8. Fig. 7
Inter-laboratory comparisons between ethyl glucuronide concentration in hair samples measured in the Labor Krone and at the National Health Laboratory at the University of Luxembourg (Dr. Yegles).
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9. Fig. 8
The error profile based on the extended uncertainty of measurement U at 99% confidence intervals as a function of the calibration EtG levels in hair.
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