Comparison of two methods for the extraction of ethylglucuronide from hair.

The aim was the comparison between the Society of Hair Testing (SoHT) consensus for the use of alcohol markers which powdering hair for the extraction of ethylglucuronide (EtG) in water and extraction using the patented M3 Reagent Test kit on cut hair. Hair samples were cut into small segments and washed twice with methanol and diethyl ether. The SoHT-Consensus entails the extraction of pulverised hair in water. This is obtained by incubation of 25 mg of hair at room temperature overnight and 2 h sonication, even if the overnight incubation is not mandatory. The M3 method entails incubation of 25 mg of cut hair with the M3-Reagent at 100°C for 60 min. After centrifugation, the supernatant is injected into a liquid chromatography-tandem mass spectrometry (LC-MS/MS). Samples (191) were collected in the APSS laboratory in Trento, Italy, between 2021 and 2022. The limit of quantification (LOQ) was set at 5 pg/mg for the pulverised and M3-Reagent methods. Assays showed good linearity above the range of LOQ-300 pg/mg. Precision (within 20%) values were also obtained using both methods. In the Passing-Bablock linear regression, the final regression curve between M3 (y) and the pulverising method (x) showed good agreement; the Bland-Altman analysis did not show any significant bias between the two methods. The M3-Reagent method, due to cut hair use, is easy to perform, saves time and allows for a smaller sample quantity loss with use of nondisposable grinding jars for the ball mill to obtain the extraction of EtG.