[Multiple headspace solid-phase microextraction after matrix modification for the determination of ethyl carbamate in...

A method based on multiple headspace solid-phase microextraction (MHS-SPME) combined with gas chromatography for determining ethyl carbamate (EC) in various alcoholic beverages was established. A novel polyethylene glycol/hydroxy-terminated silicone oil fiber was used instead of commercial ones because of its high extraction ability. Anhydrous sodium sulphate was added to modify the matrix and the extraction efficiency of EC was greatly improved. The optimum conditions for MHS-SPME were as follows: extraction time, 10 min; extraction temperature, 35 degrees C; Na2SO4 addition, 4.0 mg Na2SO4 per microliter of sample; volume of sample, 20 microL. The proposed method was linear in the range of 0.04 to 100 mg/L with a correlation coefficient of 0.999 7. The limit of detection was 34 microg/L and the repeatability of six replicates was 2.19%. The method was used to determine EC in various alcoholic beverages. The concentrations obtained were compared with those obtained by standard addition method and no statistically significant differences were observed. The application of MHS-SPME avoids the matrix effect, which commonly appears in SPME-based analysis. The results indicate that MHS-SPME has a great potential for EC quantification of complex samples due to its simplicity, sensitivity, reliability, ease of operation and environmental protection, especially for the analysis of a large number of samples in different matrices.