Rapid and Direct Low Micromolar NMR Method for the Simultaneous Detection of Hydrogen Peroxide and Phenolics in Plant Extracts

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• 作者：Pantelis Charisiadis ; Constantinos G. Tsiafoulis ; Vassiliki Exarchou ; Andreas G. Tzakos ; Ioannis P. Gerothanassis
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2012
• 出版时间：May 9, 2012
• 年：2012
• 卷：60
• 期：18
• 页码：4508-4513
• 全文大小：295K
• 年卷期：v.60,no.18(May 9, 2012)
• ISSN：1520-5118

文摘

A rapid and direct low micromolar ¹H NMR method for the simultaneous identification and quantification of hydrogen peroxide and phenolic compounds in plant extracts was developed. The method is based on the highly deshielded ¹H NMR signal of H₂O₂ at 10.30 ppm in DMSO-d₆ and the combined use of picric acid and low temperature, near the freezing point of the solution, in order to achieve the minimum proton exchange rate. Line widths of H₂O₂ below 3.8 Hz were obtained for several Greek oregano extracts which resulted in a detection limit of 0.7 渭mol L^鈥?. Application of an array of NMR experiments, including 2D ¹H鈥?sup>13C HMBC, spiking of the samples with H₂O₂, and variable temperature experiments, resulted in the unequivocal assignment of H₂O₂ precluding any confusion with interferences from intrinsic phenolics in the extract.

Keywords:

hydrogen peroxide; ¹H鈭?sup>13C HMBC; NMR; phenolics; spiking; DETAPAC