Analysis of Ethyl Carbamate in Food Using the Aniyipu 7700 Single Quadrupole Gas Chromatograph-Mass Spectrometer
Refer to "GB 5009.223-2014 National Food Safety Standard: Determination of Ethyl Carbamate in Foods." Use gas chromatography-mass spectrometry (GC-MS) with a mixed standard of ethyl carbamate and its internal standard D5-ethyl carbamate. Perform Scan mode analysis for qualitative identification based on retention time, mass spectrum, and characteristic ion pairs. Conduct Sim mode analysis for quantitative determination using the internal standard method with D5-ethyl carbamate as the internal standard.
Experimental Conditions
Chromatographic Parameters
Injection mode: Splitless; Purge time: 0.8min; Purge flow: 50mL/min.
Liner: Glass wool-free; Injection volume: 1.0μL; Inlet temperature: 220℃;
Column: DM-Wax 60m × 0.25mm × 0.25µm
Column flow rate: 1mL/min (constant flow);
Column oven temperature program: 50°C (1 min), 8°C/min, 180°C (3 min), 10°C/min, 240°C
Mass Spectrometry Parameters
Ion Source: 240°C; Transfer Line: 250°C; Ionization Energy: 7 eV; Filament Current: 100 µA; EM Voltage:
900V; solvent delay 15min
Scan Mode: Full Scan (SCAN) and Selected Ion Monitoring (SIM); SCAN mode scan range: 40~100 amu.
Experimental Results
Analyze samples according to instrument analysis conditions, starting from low to high concentrations. The ethyl carbamate concentration points are 10.0ng/mL, 25.0 ng/mL, 50.0 ng/mL, 100 ng/mL, 200 ng/mL, 400 ng/mL, and 1000 ng/mL (containing 200 ng/mL D5-ethyl carbamate internal standard); 2.0 ng/mL, 5.0 ng/mL, 10.0 ng/mL, 15.0 ng/mL, and 40.0 ng/mL (containing 200 ng/mL D5-ethyl carbamate internal standard). Plot the response ratio of analyte to internal standard on the x-axis and the concentration ratio of analyte to internal standard on the y-axis. Construct calibration curves using least squares regression. The squared correlation coefficient r for both curves²One for 0.9999 and one for 0.9987.
Perform 6 replicate injections of urethane (with internal standard D5-urethane at concentration 200ng/mL) for 10ng/mL, 400ng/mL, and 1000ng/mL; compare retention times and peak areas.
Prepare urethane standard solutions at concentrations of 2.0ng/mL and 5.0ng/mL. Using signal-to-noise ratios (S/N) of 3 and 10 as the limits of detection and quantification, respectively, the limit of detection for urethane is approximately 2.0ng/mL, and the limit of quantification is approximately 5.0ng/mL. The instrument meets the requirements for determining urethane in food.
This study establishes a method for determining ethyl carbamate in food using gas chromatography-mass spectrometry. The method demonstrates excellent linearity, low detection limits, and good repeatability, making it suitable for ethyl carbamate analysis in food samples.