南海砗磲Sr/Ca比值测试:XRF和ICP-OES方法对比研究（英文）

Measurement of Sr/Ca Ratio in Tridacna spp.Shells from South China Sea:A Comparison of SR-XRF and ICP-OES Analysis Methods

对采自中国南海的5个砗磲(1个现代砗磲、4个化石砗磲)进行了两种高分辨率Sr/Ca比值分析。电感耦合等离子体发射光谱法(ICP-OES)得到的Sr/Ca比值呈现出年周期变化,且与海表面温度呈现负相关关系,这表明Sr/Ca可作为良好的SST替代性指标。ICP-OES是测试砗磲壳体Sr/Ca常用的方法,但大量的样品需要钻样及预处理,相当耗时。而同步辐射X射线荧光分析(SR-XRF)可以克服这些缺点,它只需要前期的样品制备,并允许固态样品原位无损快速分析,具有高空间分辨率(微米级)、高灵敏度和多元素分析的特点。在本研究中,我们用SR-XRF方法测试砗磲样品化学元素的可行性。据查阅,目前尚未有类似的相关研究文献。本文实验结果显示SR-XRF数据能够揭示元素含量及其比值变化。且SR-XRF测得的砗磲Sr/Ca比值与ICP-OES分析方法测得的Sr/Ca通过相关统计分析发现其显著性水平p值(5个砗磲样品的p值均<0.05)非常显著,表明高分辨率SR-XRF测得的砗磲Sr/Ca比值在一定程度上代替ICP-OES分析方法的可能性非常大。SR-XRF方法在砗磲重建古气候领域有很大的应用前景。

Two different analysis methods were applied and compared for determining high-resolution Sr/Ca ratio profiles of one modern(live-caught)and four fossil(dead-collected)Tridacna spp.samples from South China Sea.The Sr/Ca profileof Tridacna gigas in the South China Sea determined by Inductively coupled plasmaoptical emission spectrometry(ICP-OES)had well defined annual cycles and wassignificantly,negatively correlated with sea surface temperature,implying thatthey can be used as good proxies of historical Sea Surface Temperature(SST).ICP-OES is an commonly used method for measuring Sr/Ca ratios in Tridacna spp.shells,but it needs ex-situ,time-consuming chemical pretreatments usingvariable acids and considerable amounts of sample.While the synchrotron radiation X-ray fluorescence(SR-XRF)technique does not have these shortcomings,itrequires little sample preparation and allows rapid in situ analysis of solid-state samples at high spatial resolution(submicron scales),and it is characterized by non-destructive,high sensitivity,and multi-elemental distribution.Inthis study,we tested the feasibility of determining chemical elements in shellsamples of Tridacna spp.by using SR-XRF.To the best of our knowledge,no similar studies have been reported in the literature.Our study showed that the data of SR-XRF can reflect the elements contents and their ratios change.SR-XRFderived Sr/Ca ratio profiles are significantly correlated with those from ICP-OES(P-values for five Tridacna spp.samples are all<0.05);therefore,SR-XRF can be a promising alternative to ICP-OES.And it has a broad application potential in palaeoclimate reconstructions by using Tridacna spp..