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同步辐射X射线荧光光谱分析(SRXRF)是一种基于同步加速器光源与X射线荧光光谱分析(XRF)相结合的原位分析方法,可以直接对沉积物进行扫描获得每个点的能谱图,从而计算元素含量的相对变化。但是由于荧光光谱定性和定量分析中存在的问题,国内发表文献中各种XRF原位分析数据均以相对含量或者计数表示。本文通过对各种标准物质(土壤、沉积物和岩石)的SRXRF分析,结合标准样品的定量数据,对同步辐射X射线荧光光谱的定量方法进行了研究。鉴于元素质量数和谱线强度的差异,不同元素需要运用不同的归一方法。对于K和Ca元素,采用ROI_(0-195)背景归一;Ti元素采用ROI_(293-303)背景归一;Mn元素采用ROI_(214-222)背景归一;而较高序数的元素Fe采用拟合康普顿散射峰归一。通过上述归一方法,我们获得了K、Ca、Ti、Mn和Fe元素的定量标准曲线,相关系数分别为0.89、0.98、0.96、0.93和0.98。运用标准样品对各元素的定量标准曲线进行检验,结果表明:Fe元素含量预测的平均相对偏差小于10%,K、Ca和Ti的平均相对偏差小于20%,Mn的相对偏差较大,为35.9%。从总体上看,SRXRF获得的数据可以基本满足湖泊沉积物中元素分析的定量化需求。为验证SRXRF方法能否揭示元素含量的季节性变化,我们对四海龙湾纹层沉积物进行了分析,按选定的归一方法计算样品中元素特征谱线的强度,利用各元素的标准曲线计算岩芯沉积物中元素含量。K、Ca、Ti、Mn和Fe元素含量具有明显的季节韵律变化,浅色碎屑微层中Ti和Ca含量较高,而Mn和Fe丰度的高值对应于暗色有机质-碎屑混合层。初步研究结果表明同步辐射X射线荧光光谱分析可以揭示湖泊中沉积的元素的季节性变化,对研究过去季节-年尺度的古气候、古环境变化具有重要的科学意义。
Synchrotron radiation X-ray fluorescence spectroscopy (SRXRF) is an in situ analysis method based on the synchrotron light source combined with X-ray fluorescence spectroscopy (XRF), which can directly scan the sediment to obtain the energy spectrum of each point, To calculate the relative changes in elemental content. However, due to the problems existing in the qualitative and quantitative analysis of fluorescence spectra, all kinds of XRF in-situ analysis data published in the domestic literature are expressed by relative content or count. In this paper, the quantitative methods of synchrotron radiation X-ray fluorescence spectrometry were studied by SRXRF analysis of various reference materials (soil, sediment and rock) combined with the quantitative data of standard samples. Due to the differences in element mass and spectral line intensity, different elements need to use different normalization methods. For the K and Ca elements, the ROI_ (0-195) background is normalized; the Ti element is normalized by the ROI_ (293-303) background; the Mn element is normalized by the ROI_ (214-222) background; and the higher ordinal elemental Fe The fitted Compton scattering peak is normalized. Through the above normalization method, we obtained the quantitative standard curves of K, Ca, Ti, Mn and Fe, the correlation coefficients were 0.89, 0.98, 0.96, 0.93 and 0.98 respectively. The results showed that the average relative deviation of Fe content was less than 10%, the average relative deviation of K, Ca and Ti was less than 20%, and the relative deviation of Mn was 35.9 %. Overall, the data obtained by SRXRF can basically meet the quantitative requirements of elemental analysis in lake sediments. To verify whether the SRXRF method can reveal the seasonal variation of elemental content, we analyzed the siliceous sediments in Silong Bay and calculated the intensities of the characteristic lines of the elements in the samples according to the selected normalization method. Using the standard curve of each element, Element content in core sediments. The contents of K, Ca, Ti, Mn and Fe have obvious seasonal rhythms, and the content of Ti and Ca in the light colored clastic microlayer is relatively high, while the high values of Mn and Fe abundance correspond to the dark organic matter - clastic mixed layer . The preliminary results show that synchrotron radiation X-ray fluorescence spectroscopy can reveal the seasonal variation of elements deposited in lakes, and is of important scientific significance for the study of paleoclimate and paleoenvironmental changes in past seasons-years.