Development Of Determination Method For Ethyl Carbamate In Soy Sauce

Ethyl carbamate (EC) is a kind of genotoxic carcinogens, which is known to cause tumours on the lungs, lymph nodes, liver and other diseases. It is determinate that EC occurs at trace amounts in many fermented foods and beverages. Because of the low level of EC, present pre-treatment methods used by most of determination methods have time-consuming and large-scale use of organic solvents shortcomings.A method of headspace solid-phase micro-extraction combined gas chromatography-mass spectrometry (HS-SPME-GC/MS) was developed and applied for the determination of ethyl carbamate in soy sauce.75μm CAR/PDMS fibers were chosen to extract the ethyl carbamate from the soy sauce. After5mL of soy sauce (adjusted to pH7.5) equilibrated10min at70℃under800rpm, the CAR/PDMS fiber was inserted into the vial for30min then injected into GC-MS for10min. Under this extraction conditions, the limits of detection were1.0μg/mL. The recoveries of ethyl carbamate in soy sauce were70.56-129.21%. The precision (RSD) was3.69%(intraday) and8.50%(interday).HS-SPME-GC/MS was applied to analysis of ethyl carbamte in different brands of commercial soy sauce products. All samples were determined with the standard addition method and the content of EC was obtained by extending method. The results showed that it was common to detect ethyl carbamate in soy sauce. Because of the different conditions of samples, such as raw materials, fermentation, place of production, the concentrations of ethyl carbamate has large differences.The developed HS-SPME-GC/MS method was validated by AOAC method<AOAC Official Method994.07>, which was recommended by AOAC to determine ethyl carbamate in alcoholic beverages and soy sauce. And the results of this method was correlated well (R2>0.95) with AOAC method. It was further proved that the accuracy of HS-SPME/GC/MS method was suitable. The HS-SPME/GC/MS technique is reliable for the determination of ethyl carbamate in soy sauce.