Review of energy-dispersive X-ray fluorescence on food elements detection

Energy-dispersive X-ray fluorescence (EDXRF) is a physical rapid detection method to analyze the types of elements through the energy characteristics of fluorescent X-ray particles. When applied to the detection of food element content, it not only needs simple sample pretreatment but also the element measurement time generally does not exceed 10 min to have the accuracy of μg/g, which can greatly reduce the time and cost of detection. Due to the limitations of the EDXRF instrument and measurement mechanism, it has low sensitivity to light elements in food, and the detection sensitivity varies with elements in food element analysis. For example, the detection sensitivity of Ca, Mg, Fe, Zn, Cu and other elements concerned by people is not high when the content is low, and the measurement accuracy is extremely dependent on the detector resolution. However, with the improvement of detector performance and algorithm optimization of EDXRF, the detection limit of this technology can reach 0.1 μg/g, the detection of trace elements has also been improved, which has made a new breakthrough in the field of food element detection. Therefore, this paper reviews that in recent 20 years, in order to overcome the various difficulties of EDXRF in food detection, the hardware optimization of EDXRF (For example, the development of an analyzer without sample preparation can greatly reduce the time required for the detection of food elements, and a series of instruments combined with EDXRF and cluster capillary technology can greatly improve the excitation efficiency of lighter elements in food. The spectrometer with a high-resolution detector can improve the detection accuracy of target elements with low content in food) and in order to solve the problem of spectrum resolution in food detection, (For example, the wavelet transform method which has good performance in spectrum smoothing, identifying weak peaks and maintaining peak shape is applied to EDXRF spectrum resolution, which can better solve the problem that the X-ray characteristic peaks of elements with a low atomic number in food are submerged) the reform and innovation of spectrum resolution methods are introduced. This paper summarizes and analyzes the representative application examples of EDXRF in food safety detection, discusses the advantages and disadvantages of EDXRF compared with other rapid detection or food detection methods in different situations, concludes its application conditions, and discusses the application prospect of EDXRF technology in the field of food detection.     

Analysis of trace elements in different three region coals in Erzurum (Turkey): a study using EDXRF

Analysis by energy dispersive X-ray fluorescence (EDXRF) spectroscopy of A?kale, Balkaya and Sütkans coal in Erzurum (Turkey) has been carried out for the determination of their elemental composition, using an annular and radioisotope source. The characteristic K X-rays of the different elements were detected with Si(Li) and Ge(Li) detectors. The analysis were performed on coal samples and the results were compared.     

Elemental analysis of trace elements in fly ash sample of Yata?an thermal power plants using EDXRF

Fly ash samples collected by means of an electrostatic precipitator from the lignite-fired Yata?an Power Plants of the located in Turkey was analysed using X-ray fluorescence technique. Five trace elements, namely Nd, Ba, Sr, Mo and As were quantified using XRF. These concentration values can be helpful in developing a environmental pollution abatement approach for various applications of fly ash such as cement manufacture, wastewater treatment, lightweight contraction aggregate, ceramic production, and secondary source in recovery of valuable elements. Present results compared with results of the Kemerkoy thermal power plants [?ahin Y, Karabulut A, Budak G. A practical method for the analysis of overlepped peaks in energy dispersive X-ray spectra. Appl Spectrosc Rev 1996;31:333-45].     

高能偏振能量色散X射线荧光光谱仪测定地质样品中稀土元素

由于稀土元素本身的特点及以往X射线荧光光谱仪的局限性,用XRF方法快速测定地质样品中稀土元素一直是个难点。探讨了有效解决该问题的途径。采用粉末压片制样,应用Epsilon 5型高能偏振X射线荧光光谱仪(HE-P-EDXRF)建立了土壤、岩石和水系沉积物中稀土元素La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb,Lu和Y的EDXRF分析方法,对分析线,二次靶,基体校正方法及校准曲线的回归等进行了探讨。结果表明,La,Ce,Pr,Nd和Y的校准曲线的相关系数r>0.99,其余元素的相关系数也均在0.969以上;Pr的检出限为4.09,其余元素的检出限在0.03~2.13之间;对岩石标准物质GBW07105连续测定10次,RSD在0.81%~8.35%;检验样本的EDXRF测定值与电感耦合等离子体质谱法(ICP-MS)测定值平均相对偏差在4.4%~15.4%之间,除Gd外其余元素的平均相对偏差均在15%以内,其中较好的为Y(4.4%),La(8.3%),Ce(8.3%),Nd(8.6%)。综上可知,本方法操作简单,能够实现大批量的岩石、土壤、水系沉积物中稀土元素的快速准确测定。     

A Review of Application of Total Reflection X-ray Fluorescence Spectrometry to Water Analysis

Abstract

The aim of this article is to review the literature on the application of the total reflection X-ray fluorescence (TXRF) spectrometry for the determination of the chemical composition of aqueous samples. Details of the main stages of the analytical procedures are described. Special attention is given to the sample preparation procedure, current instrumentation, and potential error sources when analyzing the water samples of varying compositions. The examples of matrix effects and spectral interferences as well as the analytical figures of merit are also presented.     

掠出射X射线荧光分析

掠出射X射线荧光分析技术是全反射X射线荧光分析技术的延伸和发展，文章介绍了掠出射X射线荧光分析技术的形式，特点，基本原理和作者在实验室搭建的实验装置，简述了掠出射X射线荧光分析技术的发展史，以及该技术在化学元素微量和痕量分析及薄膜特性分析等领域中的应用，展望了这种技术今后的发展前景。     

基于PCA-BP神经网络的EDXRF分析测定地质样品中铁、钛元素含量的应用研究

为实现地质样品中元素含量的准确预测,提出了基于主成分分析(PCA)的改进型BP神经网络模型。采用X荧光光谱法,对新疆西天山地质样品中Fe,Ti,V,Pb和Zn等元素进行测量,将得到的X荧光计数作为输入变量,应用该模型对未知地质样品中Fe和Ti元素进行定量预测。结果表明：主成分分析与改进型BP神经网络模型取得了较好的预测效果,预测结果与化学分析值的相对误差小于3%,为地质样品元素含量预测提供了一种新型有效的方法。     

用同步辐射X荧光测量大鼠脑中微量元素的分布

采用同步辐射微探针技术研究了正常大鼠脑中的微量元素的分布,并给出了二维空间分布图.结果显示:Cl,Ca,Zn,主要集中分布在海马区,K,主要分布在海马和 皮层,而,Cu,的分布则相对无规律.元素的聚类分析结果表明,Cl,和,K,的分布相关性较好.由于同步辐射,X,荧光技术可以更直观地给出脑组织的二维元素分布, 因此这种方法可用于研究发生病变的脑中微量元素的变化.     

衍射光学元件车削补偿技术的研究

超精密单点金刚石车削加工是高精度衍射光学元件制造的重要方法,但是以往的加工方法是直接一次车削加工成型,无法实现具有加工-检测-补偿加工-检测的闭环控制特点的超精密加工,从而导致零件精度较低。针对这种加工技术的缺陷,通过研究衍射光学元件金刚石车削过程和面形状误差补偿,对表面轮廓仪实际测量的轮廓数据进行处理,计算出实际车削曲线与理想曲线之间的法向残余误差,以此获得新的金刚石车削加工轨迹,实现衍射光学元件的超精密闭环控制加工。利用单点金刚石车床对口径78的衍射光学元件进行补偿加工试验,最终使其PV值由10.4 m经过一次补偿加工后降为4.3 m。     

纳米材料的同步辐射研究

近年来,科学家们在纳米材料的生长及应用研究等诸多方面取得了巨大的进展.然而,由于受到表征手段的限制,纳米科技领域的许多关键科学问题至今仍未得到清楚的解答.同步辐射具有多种独特优点,随着国内第三代同步辐射光源的逐步发展,基于同步辐射的各种实验技术将为实时、原位、动态地表征纳米结构提供功能强大的研究平台.文章简单介绍了基于同步辐射的一些新型纳米结构表征技术,并根据作者的研究举例说明了同步辐射技术在纳米材料研究方面的一些优势.     

铅锌矿区土壤重金属的EDXRF分析

铅锌矿区及附近土壤由于受铅锌矿开采和选冶影响,受到普遍污染,Pb和Zn含量高,浓度范围宽。由于谱线重叠,高含量Pb严重干扰As的测定。同时高含量Pb和Zn的土壤标样缺乏。针对以上3个问题,该工作研究探讨了有效解决途径,建立了铅锌矿区土壤重金属Pb,As,Cd,Cu和Zn等的EDXRF分析方法。所建方法的可测量浓度,Pb为4.4～23 600 μg·g-1,Zn为7.0～39 400 μg·g-1,方法检出限分别为1.1和0.9 μg·g-1,平均相对误差分别为7.6%和6.2%。     

卷积完全匹配层在空爆电磁脉冲2维模拟中的应用

 在分析不同类型完全匹配层特点的基础上,选用了卷积形式完全匹配层（CPML）截断空中核爆电磁脉冲数值模拟的开放边界。从自由空间中电磁波的平面波解和分裂形式的完全匹配层出发,构造了未分裂形式的完全匹配层,应用傅里叶变换的卷积定理,推导出2维旋转椭球-双曲正交坐标系下卷积形式完全匹配层介质中电磁场的迭代形式的离散方程。计算表明,采用CPML吸收边界方法使得截断的外边界处的场的计算误差大大减少。     

2H nuclear magnetic resonance study of deuterated water dynamics in perfluorosulfonic acid ionomer Nafion

We have employed deuteron nuclear magnetic resonance (NMR) spectroscopy in order to study the dynamics of the deuterated water (D₂O) molecules introduced into a perfluorosulfonic acid ionomer Nafion (NR-211) film. According to the ²H NMR spectral analysis, the deuterated water molecules at low temperatures occupied either relatively rigid or mobile sites up to the temperature T_M=240 K where all the deuterated water molecules became mobile. The temperature-dependent NMR linewidths sensitively reflected the motional narrowing of the rigid and mobile sites, and the NMR chemical shift reflected significant changes in the hydrogen bonds of the deuterated water. While a slow- to fast-limit motional transition was manifested at T_M in the laboratory-frame NMR spin–lattice relaxation, the rotating-frame spin–lattice relaxation indicated no bulk liquid water state down to 200 K.     

基于散射实验极化靶的2.5T/1.3K的动态核极化(DNP)系统的开发

动态核极化法(Dynamic Nuclear Polarization, DNP)是利用热平衡下的电子在磁场中的高自旋极化率转移到原子核自旋的技术,从而极大的提高原子核自旋极化率。多种动态极化靶材料已广泛的用于自旋物理散射实验。本文介绍一种简单实用,共同开发的日本山形大学DNP系统,包括超导磁场,氦4蒸发恒冷器,微波系统以及NMR核磁共振检测系统,测得中子靶材料氘带丁醇(D-butanol)中氘核的极化率在2.5T/1.3K达到+6.5%。     

X射线荧光在地质材料卤族元素分析中的应用评介

卤族元素氟、氯、溴、碘广泛分布在地圈、水圈和生物圈,它们是矿产资源,也是许多地学研究的信息载体,更与人类生活紧密相关.卤族元素分析是地质分析的重要组成部分,而X射线荧光光谱分析方法在当今的卤族元素分析中占有重要地位.本文收集我国1988年—2020年间X射线荧光光谱分析地质材料氟、氯、溴、碘的文献126篇,在简述卤族元...     

同步辐射X射线荧光微探针技术测定熔融包裹体中的微量元素

采用同步辐射X射线荧光微探针无损分析技术,对吉林龙岗火山群地幔捕掳体中的斜方辉石矿物及其熔融包裹体进行了测试,并用美国玻璃标样(NIST 612)标定出K,Sc,Ti,Cr,Mn,Fe,Co,Ni,Cu,Zn,Ga,Sr,Y等13种元素的含量.其中,斜方辉石中的Cr?,Mn?,Fe?,Ni等元素含量与波长色散电子探针分析结果相对误差分别为15%,5%,7%,8%.包裹体中过渡族元素球粒陨石标准化曲线型式与中子活化全岩分析结果相似,反映原始岩浆在上升过程中经历了部分熔融或分离作用     

A TEM study of the stability of intermetallic precipitates in Zircaloy nuclear reactor components

Transmission electron microscopy (TEM) has been used to characterise the radiation-induced changes in Zr(Cr,Fe)₂ intermetallic precipitates present in Zircaloy-2 and -4 nuclear reactor components. The results show that the precipitates become completely amorphous at low fluences (<1 × 10²⁴ n·m⁻²) during low temperature neutron irradiation (about 330 K) with no associated chemical composition change. At higher temperatures (about 573 K), a duplex amorphous-crystalline structure is produced. The precipitates retain a crystalline core surrounded by a peripheral amorphous layer that advances inwards with increasing fluence. The amorphous outer layer is coincident with a depletion of Fe that is dispersed into the surrounding hcp -phase matrix. Subsequent post-irradiation heat-treatment below the amorphous phase recrystallisation temperature results in the back-diffusion of Fe into the precipitates.     

X射线荧光微区分析结合电感耦合等离子体质谱法进行保健食品中元素含量的测定

X射线荧光光谱微区分析法既有X射线荧光光谱法快速、简便、无损检测等特点,又可对保健食品表面的元素分布进行检测,电感耦合等离子体质谱法具有检出限低、线性范围宽、多元素同时测定等优点,旨在建立一种X射线荧光光谱微区分析法和电感耦合等离子体质谱法联合测定保健食品中元素种类、分布及含量的方法.利用X射线荧光光谱微区分析技术对一...