An evaluation of washing and extraction techniques in the analysis of ethyl glucuronide and fatty acid ethyl esters from hair samples

Letter to the Editor—Hair Ethanol Glucuronide (EtG) and Washout Effects: Can and Should Pre‐Analytical Washout Effects be Assessed During the Method Validation Phase?

“…Although an organic, methanol has the ability to dissolve polar compounds and is one of the common solvents used for hair washing described in these methods. Consequently, its ability to extract EtG during this process can occur as well (as supported by Bossers et al, [9]) and this may be the medium as to how washout effects have occurred. Whilst not re-simulating actual real-life events, experiments during method validation investigating hair EtG washing steps and the solvents used (following in line with Bossers et al, (9) and Luginb€ uhl et al's (5) research into washout effects) may also be considered to determine the extent it may have on analytical quantitation.…”

“…Consequently, its ability to extract EtG during this process can occur as well (as supported by Bossers et al, [9]) and this may be the medium as to how washout effects have occurred. Whilst not re-simulating actual real-life events, experiments during method validation investigating hair EtG washing steps and the solvents used (following in line with Bossers et al, (9) and Luginb€ uhl et al's (5) research into washout effects) may also be considered to determine the extent it may have on analytical quantitation. In addition, comparing multiple short-term exposures as well as extended exposures may also offer different insights into how washout effects arise as we can only speculate on the former.…”

“…In some of these methods, different volumes were used and the length of time for the washing process was either longer (up to hours), shorter, or not specified. In the study conducted by Bossers et al (9) specifically investigating the effect of washout effects during the sample preparation stage, they observed that even organic solutions can induce washout with effects of up to 50% in losses.…”

Alcohol Biomarkers in Hair

“…Experiments to find a common procedure for FAEE and EtG led to the proposal of washing the hair sample with dichloromethane and methanol followed by addition of 1 mL of methanol and sonication for 30 min to extract the FAEEs and EtG from hair [119]. It was tried to save the liquid extraction and to submit the washed hair pieces directly with phosphate buffer to HS-SPME at 90 C (M. Hastedt, F. Pragst, unpublished results).…”

“…Positive chemical ionization and MS/MS (88, 101, and M 1 1 for FAEEs, and 93, 106, and M 1 1 for FAEEs-D5) were also reported but without data about the performance[119] or with unreliable results because of other experimental reasons[118]. Positive chemical ionization and MS/MS (88, 101, and M 1 1 for FAEEs, and 93, 106, and M 1 1 for FAEEs-D5) were also reported but without data about the performance[119] or with unreliable results because of other experimental reasons[118].…”