A new method for the direct determination of acrylamide residues in poly-acrylamide (PAM) by ultra-performance liquid chromatography (UPLC)-quadrupole electrostatic field orbitrap high-resolution mass spectrometry with the Hypercarb column was developed. With being diluted by water, the PAM sample was dissolved well by high-speed stirring. After filtering through a 0.22 μm aqueous phase microporous membrane, the sample was analyzed by high-resolution mass spectrometry directly. Chromatographic analysis was carried out using a Hypercarb column, distilled water and methanol applied as the mobile phases. In addition, the column temperature was strictly set at 20℃. The sample was determined in the mode of parallel reaction monitoring (PRM). Accurate mass-to-charge ratio extraction of the target compound ion and its fragment ion were utilized with elemental composition analysis and isotope distribution of the fragment ion to further improve the accuracy of qualitative and quantitative analysis. Meanwhile, the fragmentation pattern of acrylamide was acquired. The calibration curve showed a good linearity in the range of 2-50 μg/L with the correlation coefficient of 0.9998. The limit of detection (LOD) was 1.5 μg/kg, satisfying the detection demands. The recoveries of the acrylamide were in the range of 101.3%-107.1%. The relative standard deviations (RSD) were 3.1%-4.1%. The applications indicated that the mass percentages of AM in PAM were in the range of 0-0.43%. The proposed method is easy, fast, sensitive and suitable for the determination and confirmation of acrylamide residues in PAM.
Keywords: acrylamide (AM); poly-acrylamide (PAM); quadrupole electrostatic field orbitrap high-resolution mass spectrometry; ultra-performance liquid chromatography (UPLC).