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1.
The present work describes a metallic hydride atomizer for atomic absorption spectrometry, by evaluating the performance of the Inconel 600® tube. For this purpose, stibine was used as the model volatile compound and antimony determination in river and lake sediments and in pharmaceutical samples was carried out to assess the metal furnace performance. Some parameters are evaluated such as those referring to the generation and transport of the hydride (such as KBH4 and acid concentrations, carrier gas flow rate, injected volume, etc.), as well as those referring to the metal furnace (such as tube hole area, flame composition, long-term stability, etc.). The method presents linear Sb concentration from 2 to 80 μg L−1 range (r > 0.998; n = 3) and the analytical frequency of ca. 140 h−1. The limit of detection (LOD) is 0.23 μg L−1 and the precision, expressed as R.S.D., is less than 5% (40 μg L−1; n = 10). The accuracy is evaluated through the reference materials, and the results are similar at 95% confidence level according to the t-test. 相似文献
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Cadmium concentration in lake sediments is determined by suspending the solid samples in a solution containing 5% (v/v) concentrated nitric acid and 0.1% (v/v) Triton X-100. Three modifiers were tested for the direct determination. The furnace temperature programmes and appropriate amount for each modifier were optimised to get the highest signal and the best separation between the atomic and background signals. The drying stage is performed by programming a 400 °C temperature, a ramp time of 25 s and hold time of 10 s on the power supply of the atomiser. No ashing step is used and platform atomisation is carried out at 2200 °C. W–Rh permanent modifier combined with conventional modifier by delivering 10 μl of 0.50% (w/v) NH4H2PO4 solution was the best chemical modifier for cadmium determination. This modifier also acts as a liquid medium for the slurry, thus simplifying the procedure. Calibration is performed using aqueous standards in the 1–5 μg l−1 range. The optimised method gave a limit of detection of 0.56 ng ml−1, characteristic mass of 10.1±0.8 pg for aqueous standard, 9.6±0.7 pg for slurry samples containing different Cd concentrations and good precision (7.6–5.2%). The method was validated by analysing four certified reference lake sediment materials: LKSD-1, LKSD-2, LKSD-3 and LKSD-4; satisfactory recoveries were obtained (90.0–96.3%) and no statistical differences were observed between the experimental and the certified cadmium concentration. The developed methodology was used to determine cadmium in three ‘real’ sediment samples from lakes in the area of Wielkopolski National Park, Poland. 相似文献
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铁对藻类生长的影响及其光谱识别研究展望 总被引:3,自引:0,他引:3
铁(Fe)是藻类生长所必需的微量营养元素,在藻类对氮的吸收、固氮菌对氮的固定、叶绿素合成、卟啉生物合成、光合作用电子传输等生物过程中发挥着非常重要的作用。因此在水体富营养化治理过程中,除了要注意控制氮、磷的输入,还应考虑Fe的调控作用。遥感技术是监测水体富营养化的有效措施,应用遥感技术可以实时、大面积监测水体中藻类的生长分布情况。水体中Fe浓度的波动会使藻类细胞的代谢活动发生变化,进而反映在藻类反射光谱上,而地物特征与其光谱特征的关系是解译遥感影像的关键;研究Fe的藻类光谱效应,对于阐明湖泊中水华爆发与Fe的关系、分析水华爆发的动态过程以及建立湖泊富营养化遥感预警体系都具有重要的意义。文章基于“Fe假说”,综述了Fe对藻类生长的重要作用及藻类光谱研究进展,并对Fe的藻类光谱效应在水体富营养化遥感预警机制研究领域的应用进行了展望。 相似文献
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Multiresidue determination of UV filters in water samples by solid‐phase extraction and liquid chromatography with tandem mass spectrometry analysis
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Anna Laura Capriotti Chiara Cavaliere Susy Piovesana Roberto Samperi Serena Stampachiacchiere Salvatore Ventura Aldo Laganà 《Journal of separation science》2014,37(20):2882-2891
UV filters, contained in sunscreens and other cosmetic products, as well as in some plastics and industrial products, are nowadays considered contaminants of emerging concern because their widespread and increasing use has lead to their presence in the environment. Furthermore, some UV filters are suspected to have endocrine disruption activity. In the present work, we developed an analytical method based on liquid chromatography with tandem mass spectrometry for the determination of UV filters in tap and lake waters. Sixteen UV filters were extracted from water samples by solid‐phase extraction employing graphitized carbon black as adsorbent material. Handling 200 mL of water sample, satisfactory recoveries were obtained for almost all the analytes. The limits of detection and quantification of the method were comparable to those reported in other works, and ranged between 0.7–3.5 and 1.9–11.8 ng/L, respectively; however in our case the number of investigated compounds was larger. The major encountered problem in method development was to identify the background contamination sources and reduce their contribution. UV filters were not detected in tap water samples, whereas the analyses conducted on samples collected from three different lakes showed that the swimming areas are most subject to UV filter contamination. 相似文献
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微波消解-ICP-AES测定鄱阳湖流域沉积物中微量元素 总被引:8,自引:0,他引:8
为了研究鄱阳湖沉积物中微量元素近几年来随季节、年度及沿程的变化情况,对2003年和2005年不同季节采集的鄱阳湖流域各采样点底泥进行了ICP-AES测定.结果表明,鄱阳湖沉积物中各元素的含量随着季节和年度变化而发生一定改变,枯水期普遍大于丰水期;南矶山2005年Cu和Pb含量较2003年有所降低;蔡家湾则与南矶山相反;姚公渡2005年Cu含量也较2003年低,Pb含量则高于2003年;与鄱阳湖流域底泥背景值相比,所测几个样点的Cu,Pb,Cr和Zn含量均在一定程度上超标;除大坞河外,其余各样点As含量均在背景值范围内;从饶河到鄱阳湖入湖口处,各元素含量呈逐渐降低趋势.文章提出的研究方法操作简便,效率高,劳动强度低. 相似文献
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在异质性生境中,种内功能性状变异有助于植物对环境的适应,进而影响种群更新、群落构建和生态系统过程。探讨了种内叶经济性状的变异及受生境异质性的塑造情况。以千岛湖片段化生境中的常见种檵木(Loropetalum chinense )的幼苗为研究对象,测定了200株檵木幼苗个体水平的7个叶经济性状(比叶面积SLA、叶全碳量C、叶全氮量N等)及其对应的生境因子(郁闭度、土壤全碳量、土壤全氮量等),采用相关性检验、主成分分析和线性混合效应模型等方法探讨片段化森林中檵木幼苗的种内叶经济性状变异及生境异质性对该变异的驱动作用。结果显示:(1) 在7个叶经济性状所构成的21对相关性分析中,有12对显著相关。经主成分分析降维后,主成分1(PC1)占性状总变异的43.02%,主要与比叶面积、叶绿素浓度、叶全氮量呈正相关,与叶干物质质量分数和叶碳氮比呈负相关,体现了檵木的种内叶经济谱,可反映叶片的最大光合效率。(2)片段化对生境条件和叶经济性状均有影响。岛屿森林群落的郁闭度显著低于大陆。相对于大陆,岛屿中的檵木幼苗趋向于更小的PC1值(缓慢投资-收益策略);大岛边缘较大岛内部偏向于更小的PC1值。(3)生境因子中,郁闭度对PC1具有显著正效应。研究表明,片段化生境中的檵木在幼苗阶段存在叶经济谱,生境片段化可通过影响生境条件进而改变檵木幼苗的叶经济性状。随着生境片段化程度的加剧,檵木幼苗的叶经济性状逐渐向缓慢投资-收益策略靠拢。 相似文献
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A sediment core in Lake Qinghai in northwest China was collected in 2006. 137Cs and 210Pb activities were analyzed to investigate the chronology of the sediment core. Sb and Pb concentrations, and Pb stable isotopic ratios were analyzed to study the historical atmospheric deposition records and sources of Sb over the past 15 centuries. The Sb concentration was 4.21 ± 1.52 μg/g in the sediments, its vertical distribution of Sb shows three large peaks in the recent two centuries, 1799, 1896 and 1944, coincided with Sb contamination from large wars, respectively. The peak in 1920 responded the large earthquake that happened in northern China, which was not far away from Lake Qinghai. The Sb/Pb ratio, 206Pb/207Pb and 208Pb/206Pb results suggest that Sb and Pb were probably from the ores in South China and coals in North China before 1965, but obviously from uses of leaded gasoline after 1965. 相似文献