基于X光电子能谱的芸豆表面成分分析

X光电子能谱是一种以X射线为激发源,测定材料的成分及其化学态的电子能谱技术。本试验以4种常见芸豆为研究对象,利用光电子能谱仪测定芸豆子叶和种皮,并对其谱图进行了分析和比较。结果表明,芸豆的子叶主要是由C、O、N元素组成。黑芸豆子叶中氧碳物质的量比(nO/nC)最高,为0.26。芸豆的种皮除了有C、O、N还有Si、Ca、Zn元素,Si、Ca和Zn的含量超过子叶中的含量,花芸豆种皮氧碳物质的量比最高,为0.22。红芸豆、白芸豆和花芸豆的子叶和种皮中的碳有C—C(或C—H)、C—O(或C—N)和CO这3种存在形态,氧对应有C—O和CO 2种存在形态。黑芸豆子叶中碳的形态中还出现了OCO或者NCON结合形成的峰,氧对应有3种存在形态。芸豆种皮的碳有3种形态,氧有2种形态。

Surface analysis of different Cultivars of Beans based on X-ray photoelectron spectroscopy

X-Ray Photoelectron Spectroscopy (XPS) is a type of electron spectroscopy involving ejection of electrons from the core levels of atoms in materials by X-rays and measurement of their energy. The cotyledons and testae of different cultivars kidney beans were studied by X-ray photoelectron spectroscopy. The atomic ratio of oxygen to carbon and the detailed analysis of the contributions to the C1s peak were identified from the survey spectra as well as from the detailed C 1s and O 1s spectra. The results showed a remarkable difference between element C, O and N of different kinds of beans and relative content. The ratio of O/C between 0.19 and 0.22 is close to each other, but the O/C ratio of black kidney bean cotyledon was about 0.26, which was much higher than that for the other three kinds of kidney bean. The ratio of O/C of kidney bean testae between 0.17 and 0.22 is close to each other. The C1s peaks of colored, white and red kidney bean were curve fitted into three sub-peaks, and correspondingly O 1s peaks can be divided two sub-peaks.