火焰原子吸收光谱法测定云南蒙自石榴中微量元素

采用干灰化法消化溶解样品,用原子吸收光谱法连续测定石榴汁中的K、Na、Ca、Mg、Cu、Cr等元素的含量。系统试验了测定条件,实现了同一溶液中测定多种元素,方法简单、快速、准确。测定结果为进一步开发石榴资源提供具有参考价值的数据。     

基体分离/MC-ICP-MS测定树皮表层235U/238U同位素比率

分别从日本广岛和京都采集了香樟树(Cinnamomum camphora)树皮样品共12份,用X射线能谱仪研究了树皮表层基体元素组成,并用扫描电镜观察了树皮表层微观形貌.将树皮表层样品进行干灰化法处理后,采用DOWEX(R)1-X8型阴离子交换树脂分离基体元素,然后用多接收器电感耦合等离子体质谱仪(MC-ICP-MS)测定了树皮表层235U/238U同位素比率.研究结果表明:树皮表层主要基体元素为Al,Ca,Fe,K,Mg,Si和C,O,S;采用不同浓度硝酸淋洗DOWEX(R) 1-X8型阴离子交换树脂可实现树皮表层痕量U与基体元素的有效分离.与京都树皮表层相比,广岛树皮表层不仅U含量显著偏高(P=0.012),而且部分样品235U/238U同位素比率亦略高于其自然丰度比.     

干灰化法前处理测定茶叶中铅的影响因素

研究了用干灰化法处理茶叶样品时测定铅含量的各种因素的影响,对测定介质、灰化温度、灰化时间、溶剂的选择进行了优化,对基体影响的消除进行了探讨.     

同一产地黑木耳、白木耳元素组成的比较

收集了同一产地(贵州省贵阳市)的黑木耳、白木耳样品,采用X射线能谱仪(EDS)研究了样品的主要元素组成,采用红外光谱仪(IRS)分析了样品中存在的功能基团.经过微波消解或干灰化法处理后,采用电感耦合等离子体-发射光谱法(ICP-OES)、原子吸收光谱法(AAS)和原子荧光光谱法(AFS)测定样品中Al、As、B、Ba、...     

植物标样多元素测定的五种前处理方法比较

本文采用植物样品的五种前处理方法,即干灰化法,硝酸＋硫酸＋高氯酸法,硝酸＋硫酸＋高氯酸＋氢氟酸法、硫酸＋过氧化氢法、灰化＋碱熔法,对植物标样ＧＢＷ０７６０３作样品分解,试液用ＩＣＰ－ＡＥＳ法进行十九种常量及微量元素的测定。     

电热板消解法与微波消解法测定大气颗粒物Cu、Pb元素的对比

采用电热板消解法与微波消解法两种前处理消解方法,测定了青岛小麦岛环境监测站大气颗粒物滤膜样品的Cu、Pb含量,并对测定结果进行了分析对比.发现两种消解方法测定的Cu、Pb含量的分析精密度均较好,只是微波消解法测定值略小于电热板消解法,测定Cu元素时,两种方法不存在显著性差异,可等效使用,而测定Pb元素时,两种方法略存在差异.     

电感耦合等离子体-原子发射光谱法测定滇龙胆中的镉和铅

利用电感耦合等离子体-原子发射光谱法(ICP-AES)测定滇龙胆中重金属元素Cd和Pb,比较了干灰化法和湿化法2种样品处理方法对分析结果的影响,并测定了云南一些地区滇龙胆中的Cd和Pb含量。结果表明:采用电感耦合等离子体原子发射光谱法检测滇龙胆中的Cd和Pb,最低检出限(DL)分别为1.43ng·mL-1和1.16ng·mL-1;相对标准偏差(RSD)分别为4.37%和4.05%;回收率分别为96.25%和92.25%。利用湿法消解样品,精密度好,回收率高,优于干灰化法。干灰化法适合测定滇龙胆中Pb,但不适合测定Cd,其回收率仅为0.2%。用湿法消解样品,测定不同产地滇龙胆的Cd和Pb含量,结果表明:所测地区滇龙胆的Cd,Pb含量大大低于《中华人民共和国药典》(2005)规定的中药材重金属含量标准,符合GAP生产的要求。     

ICP-AES法测定丹参中的镉和铅

建立了利用电感耦合等离子体原子发射光谱(ICP-AES)法测定丹参中重金属元素Cd和Pb的方法,比较了干灰化法和湿化法两种样品处理方法对分析结果的影响,并测定了山东一些地区丹参中的Cd和Pb含量。结果表明：采用电感耦合等离子体原子发射光谱法检测丹参中的Cd和Pb,最低检出限(DL)分别为1.92和1.07 ng·mL-1;相对标准偏差(RSD)分别为3.14%和1.83%;回收率分别为103.05%和96.24%。利用湿法消解样品,精密度好,回收率高,优于干灰化法。干灰化法适合测定丹参中Pb,但不适合测定Cd,其回收率仅为0.1%。用湿法消解样品,测定不同产地丹参的Cd和Pb含量,结果表明：所测地区丹参的Cd, Pb含量大大低于《中华人民共和国药典》(2005)规定的中药材重金属含量标准,符合GAP生产的要求。     

火焰原子吸收法测定海南槟榔叶片中金属元素的研究

严格按照田间采样方法采集海南槟榔园的叶片, 分别采用干灰化法和HNO₃-HCLO₄混合酸消煮法消化槟榔叶片,参考其他植物样品火焰原子吸收法的测定方法, 用火焰原子吸收光谱法测定了海南槟榔叶片中的K, Ca, Na, Mg, Fe, Mn, Cu, Zn金属元素的含量。研究了不同消化方法对测定金属元素含量的影响、仪器的最佳工作条件、干扰考察、并作了方法的准确度和精密度考察。干法消化的加标回收率在98.36%～102.38%之间,RSD在0.42%～2.33%(n=6);湿法消化回收率在99.22%～103.72%之间,RSD0.58%～1.28%(n=6)。干法消化测定的八种金属元素含量稍低于湿法消化测定的含量,八种元素含量的比值在0.970 3～0.993 4之间。文章为槟榔叶片多种金属元素含量的测定提供了可靠的方法,方便了各种金属元素对槟榔的营养作用研究。     

316L不锈钢在静态液态锂中的腐蚀行为研究

利用脉冲激光诱导击穿光谱仪(LIBS)结合SEM、EDX和维氏硬度(HV)等分析手段,分析了316L不锈钢在350℃的液态锂中静态腐蚀500h后的腐蚀特性。微观形貌分析表明：样品存在较明显的晶间腐蚀,其腐蚀层厚度约为2.7μm。硬度分析表明：腐蚀后表面硬度值约HV234.72,约是腐蚀前硬度值的0.78倍。LIBS组分分析表明：经液态锂腐蚀后的样品表面Ni、Cr等元素含量相对减少;在被腐蚀区域Li元素含量随激光击打深度的增加而减少,而Ni、Cr等元素含量与之近似呈成正比递增;母材区Li元素的渗透深度约3.5μm,约是焊缝区的0.6倍。     

干灰化结合偏硼酸锂碱熔灰分ICP-AES测定生物样品中的硅铝等元素

探讨不同种类生物样品中Si和Al等10种元素的测定方法,采用干灰化结合偏硼酸锂碱熔灰分的前处理方法,用电感耦合等离子体原子发射光谱法(ICP-AES)同时测定试样中Si和Al以及Ca,Mg,Fe,Na,P,Mn,Sr,Ti。方法检出限Si为0.15μg·mL-1,Al为0.03μg·mL-1。用国家一级标准物质GBW07604(杨树叶),验证了方法的准确度及精密度,Si和Al的测定的准确度(RE)分别为-0.03%和-3%,Si和Al测定的方法精密度均小于3%,该方法已用于新研制的系列生物标准物质的定值,并取得满意结果。     

电感耦合等离子体发射光谱法/质谱法检测地衣样品中主次微量元素的方法优化

地衣是应用广泛的大气污染生物监测器。电感耦合等离子体发射光谱法/质谱法(ICP-MS/AES)是植物元素定性定量分析的重要和高效的方法。但受严重大气污染影响,我国部分地区的地衣元素水平远高于其他植物,且在空间、时间、物种和元素类别方面存在巨大差异。虽然地衣在大气污染监测方面具有良好的应用前景,但我国地衣元素分析测试方面尚缺乏专门的方法学研究,这限制了大气质量的地衣生物监测在我国的开展。因此,有必要对地衣样品元素含量的ICP-MS/AES法进行优化。以国家一级标准物质GBW10014(圆白菜)、GBW10015(菠菜)、GBW10052(绿茶)和地衣标准物质(IAEA-336)为材料,探讨了地衣样品的不同消解方法、取样量、分析谱线、同位素、内标元素及仪器参数对ICP-MS和ICP-AES结果的影响。确定了适用于大批量地衣元素测试的干法灰化-碱熔ICP-AES和微波消解ICP-MS的优化条件,该优化条件具有线性关系好(r>0.999 0)、检出限低、准确度高和精密度好的特点。以优化后的测试方法测定采自我国太行山区和南极阿德利岛的地衣样品,结果表明太行山地衣体内元素含量远高于南极阿德利岛,大气沉降对太行山地衣元素组成的相对贡献也较大。验证了优化方法的适用性,为京津冀环境治理提供科学数据和技术支持。     

原子荧光光谱法测定不同产地茶叶中As，Se，Hg和Bi四种元素含量

收集了21种中国茶叶和五种日本茶叶,经过微波或湿法消解后,采用原子荧光光谱法(AFS)测定了As, Se, Hg和Bi四种元素的含量,并用植物标准参考物质评价了分析方法的准确度。另外,还探讨了As, Se, Hg和Bi在幼龄茶树不同部 位的含量分布特征。研究结果表明：微波消解对于获得较为准确的茶叶中Hg含量分析结果必不可少;与日本茶叶相比,中国茶叶中As, Se, Hg和Bi元素含量显著偏高,但君山银针中Bi含量最低;As, Se和Hg主要积累于幼龄茶树的树皮、根 系、老叶等部位,而Bi在幼龄茶树根系、去皮树干中含量则低于AFS检测限。从本次研究结果可以初步断定,茶树并非是一种Se积累植物,中国茶叶中人体必需微量元素Se主要来源于大气气溶胶的干、湿沉降。     

Use of elemental size distributions in identifying particle formation modes

The chemical composition of particles generated during pulverized coal combustion is the consequence of their formation processes. This work aims to use the size resolved elemental composition of coal-derived particles to identify their formation modes. A size-classified bituminous coal is burnt in a laboratory drop tube furnace at 1150, 1250, and 1350 °C, respectively. The elemental composition of the size-segregated particles from coal combustion is analyzed and the total mass fraction size distributions of Si and Al are obtained. Three particle formation modes are observed in these distribution profiles. The coarse mode has the highest value of the total mass fraction of Si and Al while the ultrafine mode has the lowest one. The total mass fraction of Si and Al in these two modes is nearly independent of particle size. It is believed that the coarse mode is formed by the mineral coalescence mechanism and the ultrafine mode by the vaporization–condensation mechanism. The difference in the total mass fraction of Si and Al between the central mode and the other two indicates that the central mode is formed by different mechanisms. Based on the observation that the total mass fraction of Si and Al in this mode increases with increasing particle size, heterogeneous condensation of vaporized species on existing fine residual ash particles is proposed to account for the formation of these particles. The study of the elemental composition of the three modes represented in five categories verifies the proposed formation mechanisms for them to some extent.     

Elemental content of aerosol particles in an underground tram station

Particulate matter is an important air pollutant, especially in closed environments like a tunnel. The aim of this study was to determine the mass, black carbon, and elemental concentrations of particulate matter of two size fractions at an underground tram station in Hammarkullen, Gothenburg, Sweden. Samples were collected during June 2007 using a dichotomous virtual impactor separating the sampled aerosol particles into coarse (PM_(2.5–10)) and fine (PM_2.5) fractions. To minimize the possible influence of waiting passengers, the platform for trams going towards the suburb Angered was chosen. The elemental analysis of the samples, collected on Teflon filters, was carried out using energy dispersive x‐ray fluorescence (EDXRF) spectrometry, resulting in concentrations of 14 elements in most of the samples. Principal component analysis (PCA) was applied to identify possible sources for the elements in the particles. Owing to the tunnel environment, the elemental difference between the fine and coarse particle fractions was not as large as that in similar particles collected under normal outdoor ambient conditions. Likewise, the influence of the local weather situation was not significant. Particle content from the tram traffic was identified by PCA, with Fe being the major element in both coarse and fine particles. The particle mass concentration was higher in the tunnel compared to the ambient concentration at the monitoring station Femman in downtown Gothenburg. In some days, the mass concentration exceeded the Swedish daily ambient air quality standard of 50 µg m^?3, but it was lower than the limits in the environmental work act, 5 mg m^?3. Copyright © 2009 John Wiley & Sons, Ltd.     

Comprehensive microanalytical study of welding aerosols with x‐ray and Raman based methods

A comprehensive analysis of individual welding fume particles of different size fraction has been performed by applying of an innovative combination of the energy‐dispersive x‐ray fluorescence spectroscopy (EDXRF), micro‐Raman spectroscopy (MRS) and electron probe microanalysis (EPMA). Owing to this set of analytical techniques, a systematic study of the chemical composition along with the size, morphology and structure parameters of the collected welding particles was performed. The results show distinct interdependencies between the particles' elemental composition and their sizes and structures, which are consistent with commonly assumed mechanisms of their formation and evolution. In particular, interactions between the particles of fine and coarse fractions as well as regularities in distribution of the most toxic welding fume components (Mn and its oxides) have been observed. Copyright © 2007 John Wiley & Sons, Ltd.     

EDXRF and TXRF analysis of elemental size distributions and environmental mobility of airborne particles in the city of Riga,Latvia

Airborne particles were investigated in the central part of Riga during October 2000. Mass, black carbon and elemental concentrations of airborne particles were measured on Teflon filters from a dichotomous impactor, which samples fine (<2.5 µm) and coarse (2.5–10 µm) fractions of particles. In order to obtain more detailed information on the size distributions of different elements, a seven‐stage Batelle cascade impactor was used, in which quartz plates treated with silicone grease were utilized as backing for the different stages. Total reflection x‐ray fluorescence (TXRF) and energy‐dispersive x‐ray fluorescence (EDXRF) spectrometry were used for elemental analysis on the quartz plates and Teflon filters. The environmentally mobile part of the fine particle elements in the aerosol was determined by subtraction of x‐ray spectra measured before and after sequential leaching of the aerosol filters. The results of the different measurements show that naturally generated street dust and soil particles are dominant in coarse particles, whereas particles generated by human activities are dominant in the size fraction <0.5 µm. Copyright © 2004 John Wiley & Sons, Ltd.     

密封消解ICP-AES和ICP-MS测定中日两国茶叶中23种矿质元素

收集了13种中国茶叶和6种日本茶叶,在进行密封消解后,采用电感耦合等离子体发射光谱法(ICP-AES)和电感耦合等离子体质谱法(ICP-MS)测定了茶叶中Al,Ba,Ca,Cd,Ce,Co,Cr,Cs,Cu,Fe,La,Mg,Mn,Na,Ni,Pb,Rb,Sb,Sr,Th,U,Y和Zn等23种矿质元素的含量,并用茶叶标准参考物质(GBW07605)评价了分析方法的准确度。研究结果表明：密封消解有助于获得较为准确的茶叶中矿质元素含量的分析结果;与日本茶叶相比,中国茶叶中Cd,Co,Cr,Cs,Fe,Pb,Rb,Sb,Th,U和Zn等元素含量显著偏高(P＜0.05),预示大气重金属污染程度中国较日本严重。另外,还发现茶叶中一些矿质元素含量之间有很强的线性相关性。     

EELS study of niobium carbo-nitride nano-precipitates in ferrite

Micro-alloying steels allow higher strength to be achieved, with lower carbon contents, without a loss in toughness, weldability or formability through the generation of a fine ferrite grain size with additional strengthening being provided by the fine scale precipitation of complex carbo-nitride particles. Niobium is reported to be the most efficient micro-alloying element to achieve refinement of the final grain structure. A detailed microscopic investigation is one of the keys for understanding the first stages of the precipitation sequence, thus transmission electron microscopy (TEM) is required. Model Fe-(Nb,C) and Fe-(Nb,C,N) ferritic alloys have been studied after annealing under isothermal conditions. However the nanometre scale dimensions of the particles makes their detection, structural and chemical characterization delicate. Various imaging techniques have then been employed. Conventional TEM (CTEM) and high resolution TEM (HRTEM) were used to characterise the morphology, nature and repartition of precipitates. Volume fractions and a statistical approach to particle size distributions of precipitates have been investigated by energy filtered TEM (EFTEM) and high angle annular dark field (HAADF) imaging. Great attention was paid to the chemical analysis of precipitates; their composition has been quantified by electron energy loss spectroscopy (EELS), on the basis of calibrated 'jump-ratios' of C-K and N-K edges over the Nb-M edge, using standards of well-defined compositions. It is shown that a significant addition of nitrogen in the alloy leads to a complex precipitation sequence, with the co-existence of two populations of particles: pure nitrides and homogeneous carbo-nitrides respectively.