The acrylamide eluate (2 mL) of HPLC was injected into an MS detector
[mobile phase: (a) 0.1% (vol/vol) formic acid/water; (b)
0.1% (vol/vol) formic acid/methanol; source temperature:
600C; electrospray capillary voltage: 5.5 kV; collision energy:
30 V]. Data acquisition was performed using the selected ion
monitoring mode. The ions monitored in the sample had m/z
values of 72.04 and 75.04 for acrylamide and 13C3-labeled
acrylamide, respectively. Full-scan analyses were performed
within the mass range 50e200. The acrylamide calibration
curve was built within the range of 5.208e500 ng/g.