Origin and three-dimensional fluorescence spectrum of the chromophoric dissolved organic matter in Yangtze estuary, East China     

Fan YANG Qinghui HUANG Jianhua LI Xiaomin ZHU 《中国地球化学学报》2006,25(B08):262-262

Dissolved organic matter （DOM） is an important chemical component in natural water. Chromophoric dissolved organic matter （CDOM）, a fraction of optical properties, plays art important role in the biogeochemical cycle of nutrients in aquatic environment. People realized that DOM cycle is crucial in the global carbon and nitrogen flux, and also is inherently related to nutrients and trace metal elements. Therefore, CDOM was concerned by scientists in global oceanography and limnology fields. Water samples were collected from three sections （North Channel, South Channel and Zhuyuan） of the Yangtze （Changjiang River） estuary in March 2006 Three-dimensional excitation emission matrix （3-DEEM） fluorescence spectra were analyzed for those filtrates through Whatman GF/F filters. Dissolved organic carbon （DOC） was also measured by TOC analyzer. The tidal variety was also taken into account. The 3-D EEM fluorescence scans suggested the fluorescence characteristics of humic acid （Ex=332-344 nm, Em=439-451 nm） and fulvic acid （Ex=250-254 nm, Em=472-478 nm） were obvious, and the fluorescence group of protein-like and tyrosine （Ex=230 nm, Em=283 nm） was also found. They are mainly composed of CDOM in the Yangtze estuary. Further data analysis, especially the fluorescence index （f 450/500）, showed that terrestrial signal was rather strong （1.41-1.65） in the surface water, however, some terrestrial CDOM signals of bottom water showed excursions （1.28-1.39）. On the other hand, anthropogenic sign was impressed in the waters of Zhuyuan, which is one of the main drain outlets of Shanghai Metropolis. DOC concentrations ranged from 2.2 mg/L to 3.4 mg/L in Zhuyuan and South Channel, and from 2.0 mg/L to 2.4 mg/L in North Channel. The tide effect played a role in the composition of the CDOM measured by 3-D fluorescence scan technology.  相似文献   

氢化物发生-原子荧光光谱法测定地球化学样品中痕量碲   总被引：4，自引：4，他引：4  

范凡 《岩矿测试》2005,24(3):225-228

采用焙烧富集分离地球化学样品中痕量Te,并用氢化物发生原子荧光光谱法测定。通过实验确定出方法的最佳实验条件,在此条件下获得的检出限为0.005μg/g,线性范围0.025~10μg/g,精密度(RSD,n=8)为5.03%~9.24%。方法已用于国家一级地球化学标准物质中痕量Te的测定,结果与标准值基本相符。  相似文献   

理学3080E3型X射线荧光光谱仪维修实例   总被引：2，自引：0，他引：2  

唐晓慧 《岩矿测试》2005,24(3):237-238

介绍理学3080E3型X射线荧光光谱仪样品驱动单元及高压发生器部分的故障现象及维修实例。  相似文献   

硬玉的差热分析和紫外荧光光谱研究   总被引：2，自引：0，他引：2  

彭卓伦  彭明生  徐庆鸿 《矿产与地质》2003,17(5):630-631,635

通过对缅甸硬玉的差热分析和紫外荧光光谱研究，发现不同颜色硬玉的紫外荧光谱中的617nm处的谱峰，可能是Cr引起的；对不同颜色硬玉进行的差热分析表明，其熔融温度略有不同，说明其生长环境有一定差异，而硬玉也可能是较好的耐热材料，具一定的开发潜能。  相似文献   

ARL9400型X荧光光谱仪探测器高压部分故障分析与维修     

吴红旗 《岩矿测试》2003,22(4):307-309

简述了瑞士ARL 9400型X荧光光谱仪探测器高压部分的故障现象、分析与处理及维修方法，并给出了维修实例。  相似文献   

原子荧光光谱法测定芦荟中砷和硒   总被引：5，自引：1，他引：5       下载免费PDF全文

林章金 《岩矿测试》2003,22(3):237-238

应用AFS 820型双道原子荧光仪测定芦荟中砷和硒,方法检出限分别为As0.51μg/L;Se0.42μg/L。经国家一级植物标准物质分析验证,结果与标准值相符。5次测定相对标准偏差As<2.3%;Se<3.1%。  相似文献   

原子荧光光谱法测定化探样品时有机质对As,Sb,Bi的干扰   总被引：1，自引：0，他引：1  

汪明启  刘应汉 《地质科技情报》2003,22(1):105-109

通过研究黑龙江省森林沼泽景观区有机水系沉积物（泥炭）、土壤中As,Sb,Bi的测定结果，发现样品中的有机质对王水消解氢化物原子荧光法测定上述元素存在极大的干扰，提出采用低温（＜450℃）灰化处理可完全消除干扰。对比研究还发现，过去森林沼泽景观区的区域化探扫面资料中的As,Sb,Bi数据存在问题，应专门对其进行评价研究。  相似文献   

Enhanced red fluorescence emission in the oxygen minimum zone of the Arabian Sea     

Wiebke Breves  Rüdiger Heuermann  Rainer Reuter 《Ocean Dynamics》2003,53(2):86-97

 Depth profiles of fluorescence at several excitation and emission wavelengths were measured along with CTD data during the cruise So119 of RV Sonne in the Arabian Sea from 12 May to 10 June 1997. In addition to chlorophyll fluorescence from phytoplankton in the near-surface layer, the profiles in the oxygen minimum region well below the euphotic zone show enhanced red fluorescence. Red fluorescence intensity is inversely related to the oxygen concentration in intermediate and deep waters. A relationship to characteristic water masses of the region cannot be found in the data, and this holds also with chemical data such as DOC. Absorbance spectra of water samples taken in the oxygen minimum zone show an absorption band at 420 nm wavelength with about 50 nm bandwidth, much weaker than gelbstoff absorbance in the same wavelength range. The absorption band remains stable after sample filtration with 0.45 μm glass fibre filters. Hence, the size of the absorbing matter is in the range of dissolved molecules or particles much smaller than 1 μm. Fluorescence spectra of unfiltered samples with 420 nm excitation show a weak emission band at 600 nm and a more pronounced one at 660 nm wavelength. The trailing edge of the 660 nm band falls into the range of chlorophyll emission, thus giving rise to the observed depth profiles of red fluorescence in the oxygen minimum zone. Red fluorescence measured on samples remain stable during a few hours after sampling even in the presence of oxygen. It is not detectable after several weeks of sample storage in the dark and cannot be reproduced even after depletion of dissolved oxygen. Received: 22 May 2002 / Accepted: 18 February 2003 Responsible Editor: Andreas Oschlies Acknowledgements. This work was supported by a grant from the Federal Minister of Education and Technology, Bonn, within the frame work of the JGOFS Arabian Sea program. We are grateful to the captain and the crew of RV Sonne for their support. We are indebted to Mrs. Kirsten Neumann from the Institute of Marine Chemistry and Biogeochemistry of the University of Hamburg for providing the oxygen data, and to Mr. Nikolai Delling from the same institute for making the DOC and chlorophyll data available to us.  相似文献   

Advances in energy-dispersive X-ray fluorescence   总被引：1，自引：0，他引：1  

Utz Kramar 《Journal of Geochemical Exploration》1997,58(1):73-80

Recently, two new instruments for X-ray fluorescence analysis (XRF) with interesting features for geochemical applications came to the market. Both instruments were designed to improve the peak to background ratio, the principal factor limiting the sensitivity of XRF. Total reflection XRF (TXRF) was designed to analyse extremely small sample amounts. An instrument, using polarised X-rays (P-XRF) for excitation, is designed to reduce scattered background in spectra of bulk samples. The performance of both instruments was compared with conventional XRF-methods and ICP/MS. Results for GXR-1, GXR-2, GXR-3, GXR-4 and GXR-6 obtained with TXRF and P-XRF are in good agreement with literature data. The effective amount of sample, analysed by TXRF was 200 μg only and detection limits of ~ l μg/g were achieved. P-XRF shows considerable improved detection limits (0.25–0.5 μg/g) for bulk samples for elements with atomic numbers 42–51 (Mo-Sb) compared with conventional XRF-methods.  相似文献   

能量色散X射线荧光光谱法测定卤水中痕量溴铷砷   总被引：3，自引：4，他引：3  

樊兴涛  詹秀春  巩爱华 《岩矿测试》2004,23(1):15-18

用模拟卤水建立了能量色散X射线荧光光谱法测定卤水中溴、铷、砷痕量元素含量的方法.实验表明,方法可以直接取样测定,适用于大批量样品的测试分析.方法的精密度RSD(n＝15)小于1%,加标回收率为86.8%～101.6%.卤水中溴、铷、砷的测定结果与比色法、原子吸收和原子荧光法结果相符.  相似文献