▎ 摘　　要

In combination with 2, 4-dinitrophenylhydrazine ( DNPH ) pre-column derivatization, an ultrasound-assisted magnetic solid phase extraction method with Fe3O4 -grafted nitrogen-doped graphene (Fe3O4/N-G) nanomaterials as magnetic adsorbent was developed for the determination of acetone , acrolein , butenal, n-butanal, cyclohexanone and hexanal in environmental water samples by ultra performance liquid chromatography-high resolution mass spectrometry ( UPLC-HRMS) . The derivation conditions were optimized by single-factor experiments as follows ; the pH of water sample was adjusted to 3. 0 , and derivatization was performed for 40 min at 40 degrees C with 500 times of DNPH. As a result, the conversion ratios of 6 carbonyl compounds were in the range of 52. 1% -86. 6% . Several significant factors that affected the magnetic solidphase extraction efficiency including the amount of magnetic nanoparticles , salt concentration and kinds of desorption solvent were also optimized using a response surface methodology. The optimal conditions were as follows ; 4. 7 mg of Fe3O4/N-G was dispersed into 100 mL of water with ultrasonic extraction for 10 s. Then the adsorbents were separated by a magnet and eluted with 2 mL of acetonitrile. Finally , the eluent was dried under a mild stream of nitrogen gas and reconstituted with acetonitrile and water ( 1 : 1 , V/V) for the subsequent UPLC-HRMS analysis. It was obvious that the excessive DNPH could be almost eliminated by the MPSE process. Under the optimal conditions , a good linearity was obtained in the concentration range of 2-100 ng/L, with correlation coefficients ranged from 0. 9980 to 0. 9995. The limits of detection ( LOQs, S/N= 3) and the limits of quantification ( LOQs, S/N = 10) ranged from 0. 05 to 0. 20 ng/L and 0. 20 to 0.96 ng/L, respectively. The average recoveries at three spiked levels ranged from 74. 1% to 101. 0% with the inter- and intra-day precisions ( n=6 ) of less than 6. 3% . Moreover, the trace level of acetone , acrolein , butenal, n-butanal, and hexanal in real water samples has been successfully detected using the proposed method. Attributed to the excellent performances of Fe3O4/N-G, the proposed method was demonstrated to be simple, quick and high sensitive 14 the trace analysis of carbonyl compounds in water samples.