ABSTRACT
Phosphatidylethanol (PEth) has become a widespread marker offering an up to four weeks retrospective window to detect alcohol use. Due to the COVID 19 pandemic, ethanol-based hand sanitizers are frequently used. The aim of this study was to develop and validate a method for determination of up to seven different homologues of PEth from dried blood spots (DBS) after use of an ethanol-based hand sanitizer. Objectives of its preliminary application were to prove whether a threshold of 20 ng/mL for PEth 16:0/18:1 is reached and whether other homologues are formed as well as if positive findings of urinary ethyl glucuronide (UEtG) can be observed with respect to assess monitoring of abstinence control programs. Ten volunteers (8 occasional, 2 regular drinkers) were recruited to excessively use an ethanol-based hand sanitizer on 5 successive days. Dried blood spots and urine samples were collected daily. PEth and UEtG were determined by LC-MS/MS. In total, two volunteers with initial PEth 16:0/18:1-concentrations of 19.3 and 14.6 ng/mL exceeded the threshold of 20 ng/mL six times. Regular drinkers had starting PEth 16:0/18:1-concentrations of 242 and 354 ng/mL, showing a decline of PEth-concentrations in six out of the seven homologues over five days. In teetotalers, formation of PEth species could not be observed. Thus, not satisfying requirements in an alcohol monitoring program with initial PEth-negative blood cannot be explained by a frequent use of ethanol-based hand sanitizer only. In cases of regular alcohol consumption, PEth-homologues are not likely to be further influenced. However, results indicated that individuals with a PEth-concentration close to 20 ng/mL are at risk of exceeding the threshold by using ethanol-based hand sanitizer.