Application of Nuclear Magnetic Resonance on the Analysis of Cereals Toxins

• Main Authors: Chen-Yi Li, 李貞儀
• Other Authors: Wei-Jyun Chien
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/03317736315204224874

碩士 === 朝陽科技大學 === 應用化學系碩士班 === 96 === Nuclear magnetic resonance methods have been used to identify four mycotoxins, aflatoxin, fumonisin, zearalenone and deoxynivalenol under the same extraction condition in affinity column analysis. The chemical assignments are used to carry on a quantitative analysis to estimate the level of zearalenone in cereal sample for animal feed. Next, we monitored the change of signals in absorption and fluorescence spectra for the four mycotoxins with the introduction of cyclodextrins. The intensity enhancement and blue shift of λmax in fluorescence spectra suggest a possible association of mycotoxins with the hydrophoic region of cyclodextrin. Nuclear magnetic resconance spectral techniques are then applied to further investigate the interaction between zearalenone and β–cyclodextrin. From the NOESY spectra, intra-molecular NOE signals can be identified for H3 of zearalenone with H2, H5, H6 of β–cyclodextrin and H5 of zearalenone with H3, H5 of β–cyclodextrin. These evidences indicate that the aromatic part in zearalenone molecule associates with the interior region of cyclodextrin, which is consistent with the observation in fluorescence study. We used PFG-NMR to measure the diffusion coefficients for zearalenone in both aqueous solution and β–CD solution. Base on these diffusion coefficient data and a two-stage approximation model, the association constant for zearalenone-β-CD complex is estimated to have a value about 5.1×102 M-1.