Rapid Quantification of Ethyl Carbamate in Spirits Using NMR Spectroscopy and Chemometrics

Yulia B Monakhova,Dirk W Lachenmeier,Thomas Kuballa

doi:10.5402/2012/989174

Abstract

Ethyl carbamate (EC, urethane, C2H5OCONH2) is a genotoxic carcinogen and is regularly found in fermented food products including alcoholic beverages. In this study, the rapid method of nuclear magnetic resonance (NMR) spectroscopy in combination with partial least squares (PLS) regression is applied for the first time to the analysis of ethyl carbamate in stone fruit spirits () and unrecorded alcohols () (analysis time only 15 min per sample). The PLS procedure was validated using an independent set of samples (, , mg/L) in comparison to reference GC/MS/MS results. The NMR method was found to outperform other screening techniques based on NIR or FTIR regarding sensitivity and selectivity. The major advantage over GC/MS/MS, besides the reduced time of instrumental analysis, is that no sample preparation besides addition of buffer with internal standard is required, while for GC/MS/MS labour-intensive sample extraction is necessary prior to measurement.

Highlights

Ethyl carbamate (EC) may occur as contaminant in fermented foods and beverages with highest concentrations generally found in stone fruit spirits
The rapid method of nuclear magnetic resonance (NMR) spectroscopy in combination with partial least squares (PLS) regression is applied for the first time to the analysis of ethyl carbamate in stone fruit spirits (n = 119) and unrecorded alcohols (n = 27)
In this study, NMR spectroscopy in combination with partial least squares (PLS) regression was applied for the first time for quantitative determination of ethyl carbamate in stone-fruit spirits and unrecorded alcohols

Summary

Introduction

Ethyl carbamate (EC) may occur as contaminant in fermented foods and beverages with highest concentrations generally found in stone fruit spirits. Concerns over this compound were raised as it is possibly carcinogenic to humans [1] and its margin of exposure may reach public health relevant ranges [2,3,4]. An alternative way to decrease matrix effects is the use of derivatization of EC with xanthydrol for HPLC/MS analysis [21] Besides these quantitative reference procedures, spectroscopic techniques have been evaluated for screening analysis of ethyl carbamate, including FT near-infrared (NIR) and FT infrared (IR) spectroscopy [22, 23]. In this study, NMR spectroscopy in combination with partial least squares (PLS) regression was applied for the first time for quantitative determination of ethyl carbamate in stone-fruit spirits and unrecorded alcohols

Experimental Section

Results and Discussion

Conclusions