Effects of lactate and acetate on the determination of serum ethyl glucuronide by CZE

Abstract

The analysis of ethyl glucuronide (EtG), a marker of recent alcohol consumption, in serum with an optimized CZE assay is reported. The method uses a 0.1-mm id fused-silica capillary of 50 cm effective length that is coated with linear polyacrylamide, a pH 4.4 nicotinic acid/epsilon-aminocaproic acid (EACA) BGE, reversed polarity and indirect analyte detection. The assay is based on a 1:1 dilution of serum with deionized water and has LODs for EtG, lactate and acetate of 3.8 x 10(-7) M, 2.60 x 10(-6 )M and 2.18 x 10(-6 )M, respectively. Separation of EtG from endogenous macro- and microcomponents (anionic serum components of high and low concentration, respectively) and its quantification are shown to be possible for a wide range of lactate (stacker) and acetate (destacker) concentrations, macrocomponents that have an impact on the CZE behavior of EtG and that change after intake of ethanol. The assay has been successfully applied to the analysis of EtG, lactate and acetate in (i) sera of volunteers that ingested known amounts of alcohol and (ii) samples of patients that were classified (teetotalers and social drinkers vs. alcohol abusers) via analysis of carbohydrate-deficient transferrin.

Determination of ethyl glucuronide in human serum by hyphenation of capillary isotachophoresis and zone electrophoresis

“…The analysis of EtG represents a useful forensic tool as well as a possible method for monitoring of alcohol consumption of patients being treated for alcoholism. It covers a clinically and forensically important time window between short-term markers, such as ethanol itself, and long-term markers, such as carbohydratedeficient transferrin [3][4][5][6][7][8][9][10][11][12]. Deaths on the roads or in the workplace might be related to the after-effects of recent heavy drinking corresponding to alcoholic hangover, and the analysis of EtG or another marker of acute alcohol ingestion would prove useful to aid in the interpretation for postmortem toxicology.…”

“…For example, the concentration of lactate in serum can increase due to many factors, such as diseases (Diabetes mellitus), physical effort, and also by consumption of alcohol [22]. The effect of varying lactate concentration has a significant impact on the electrophoretic separation of EtG and conditions for CZE analysis of EtG have to be tuned very carefully to eliminate or reduce this effect as much as possible [4]. Another possibility to avoid this effect is to simplify the sample by an on-line preseparation step.…”

“…Lactate and acetate are present in serum at concentrations of 0.5-10 and 0. 4-4.0610 23 M, respectively [4,20,21], and their concentrations can be influenced strongly by the physical and health states of individuals. For example, the concentration of lactate in serum can increase due to many factors, such as diseases (Diabetes mellitus), physical effort, and also by consumption of alcohol [22].…”

“…So far, GC-MS [15] after derivatization, LC-MS or LC-MS/ MS [16,17] methods, and CZE with indirect detection [3,4] have been reported for EtG determination. The main problem of EtG determination in serum by CZE is the varying concentration of some macrocomponents in the matrix and its effect on the separation process, separation efficiency, and resolution as well as still not sufficient sensitivity.…”

Nonaqueous capillary electrophoresis for analysis of the ethanol consumption biomarker phosphatidylethanol

“…The timeliness of developing analytical methods for emerging ethanol consumption markers, e.g. ethyl glucuronide, ethyl phosphate and ethyl sulfate, is highlighted by recent studies [9][10][11].…”