Non-chromatographic atomic spectrometric methods in speciation analysis: A review

In recent years, knowledge of the different chemical forms of the elements has gained increasing importance. There has been significant progress in methods that hyphenate chromatographic separations with atomic spectrometry. These hyphenated methods can provide the most complete information on the species distribution and even structure. However, they can be lengthy, relatively costly and difficult to bring to the routine. On the other hand, it is important to remember that chromatographic techniques represent only a minor part of the separation procedures available and, in certain cases, the application of basic chemistry to sample treatments can give quantitative information about specific chemical forms. In this sense, non-chromatographic procedures can provide methods that offer sufficient information on the elemental speciation for a series of situations. Moreover, these non-chromatographic strategies can be less time consuming, more cost effective and available, and present competitive limits of detection. Thus, non-chromatographic speciation analysis continues to be a promising research area and has been applied to the development of several methodologies that facilitate this type of analytical approach. In view of their importance, the present work overviews and discusses different non-chromatographic methods as alternatives for the speciation analysis of clinical, environmental and food samples using atomic spectrometry for detection.     

砷和汞的顺序注射-蒸气发生原子吸收光谱测定

本文建立了砷和汞的顺序注射 蒸气发生原子吸收光谱测定方法。在流动注射蒸气发生原子吸收光谱测定方法的基础上 ,采用汇流技术 ,通过两个微量注射泵和一个多位选择阀的计算机程控操作 ,实现待测组分与硼氢化钠间的强氧化还原反应及其气 液分离过程。与流动注射方法相比 ,进一步大幅度节省试剂消耗 ,显著提高分析的精度及长期稳定性。在 1 2 0·h- 1 的采样频率下汞和砷的测定精度RSD分别为 2 2 %和 1 4%,检出限分别为 0 1 5和 0 0 7μg·L- 1 。方法用于地球化学标准样品的分析 ,取得满意结果。     

Bound states of Klein－Gordon equation for ring-shaped harmonic oscillator scalar and vector potentials

Solving Klein－Gordon equation with equal ring-shaped harmonic oscillator scalar and vector potentials, we obtain the exact normalized bound-state wavefunction and energy equation.     

k-quantum nonlinear Jaynes－Cummings model in two trapped ions

We have obtained a k-quantum nonlinear Jaynes－Cummings model for two trapped ions interacting with laser beams resonant to the kth red side-band of the centre-of-mass mode, far from the Lamb－Dicke regime. The exact analytic solution shows the existence of quantum collapses and revivals of the occupation of two atoms.     

石墨炉原子吸收光谱法直接测定尿中痕量锰

应用硝酸作基体改进剂 ,石墨炉原子吸收光谱法直接测定尿中痕量锰。方法简便、快速、准确 ,灵敏度高。方法的检出限为 0 .0 80 μg·L- 1,回收率为 97.2 %。对锰含量为 5 μg·L- 1的尿样测定 7次的相对标准偏差为 3.16%     

生态纺织品中重金属残留总量的测定

1　前言为提高织物的穿着性能及人体健康水平而进行的生态纺织品开发越来越受到人们的重视[1] ,所采用的许多纺织整理剂开始关注安全无害、效果持久、性能稳定等特殊要求[2 ] ,尤其是因纺织品加工工艺而引入的各种重金属元素 ,在某些安全卫生检验或环境质量控制项目中已被列入严格限制使用的化合物之列[3 ] 。但就倡导绿色消费的角度而言 ,目前人们对纺织原料环境品质仍缺乏必要的控制 ,一些较有影响的环境标志产品也将注意力放在可释放的重金属残留问题上[3 ] 。本文试图在现有方法的基础上[4～ 8] ,针对生态纺织品对重金属的限量要求 ,通…     

流动注射分光光度法测定茶叶中锗含量

有机锗具有提高人体免疫机能、降低血脂、抗癌及防癌、防衰老等多种功能。许多植物如人参、枸杞、茶叶、蘑菇中都含有有机锗 ,有些含锗食品国家已批准作为新资源性食品并引起人们的重视。锗的测定方法多采用原子吸收法[1 ] 和分光光度法[2～4] ,分光光度法具有显色速度快 ,水溶性好 ,灵敏度高等特点 ,但该法不能实现锗的快速自动检测。本文将流动注射与分光光度法联用 ,建立了一种流动注射分光光度法测定茶叶中有机锗含量的新方法。流动注射分析作为一种高效率的非色谱分离手段与多种仪器联用 ,显著提高了许多分析方法的选择性和灵敏度 ,该…     

白玉蜗牛微量元素的测定方法研究

以高压硝化罐硝化样品,采用电感耦合等离子体原子发射光谱(ICP-AES)法和火焰原子吸收(AAS)法分别测定了白玉蜗牛中的Ca,Mg,Fe,Zn,Cu,Co六种微量元素的含量, 并对两种分析方法进行分析比较, 结果表明,ICP-AES法和AAS法测定的微量元素无显著性差异。 方法回收率在92.4%～103.0%之间,相对标准偏差均小于2.98%。 实验证明,白玉蜗牛含有丰富的有益微量元素,是一种营养价值极高的绿色食品。     

Flow-injection hydride generation atomic absorption spectrometric study of the automated on-line pre-reduction of arsenate, methylarsonate and dimethylarsinate and high-performance liquid chromatographic separation of their -cysteine complexes

An automated on-line pre-reduction of arsenate, monomethylarsonate (MMA) and dimethylarsinate (DMA) using flow injection hydride generation atomic absorption spectrometry (FI-HGAAS) is feasible. The kinetics of pre-reduction and complexation depend strongly on the concentration of -cysteine and on the temperature in the following increasing order: inorganic As(V)<DMA<MMA. Arsenate is pre-reduced/complexed within less than 50 s at 70–100°C compared to 1 h at room temperature, while MMA and DMA require 1.5–2 min at 70–100°C and up to 1–2 h at room temperature. The characteristic masses and concentrations for 100 μl injections are 0.01 ng and 0.1 μg l⁻¹ in integrated absorbance and 0.2 ng and 2 μg l⁻¹ in peak height measurements, and the limits of detection are ca. 0.5 ng and 5 μg l⁻¹, respectively. In a high-performance liquid chromatography (HPLC)–HGAAS system, the -cysteine complexes of inorganic As(III), MMA and DMA are best separated within 7 min by HPLC on a strongly acidic cation exchange column such as Spherisorb S SCX 120×4 mm (5 μm) with a mobile phase containing 12 mmol l⁻¹ phosphate buffer (KH₂PO₄/H₃PO₄)–2.5 mmol l⁻¹ -cysteine, pH 3.3–3.5. Upon dilution to -cysteine levels below 10 mmol l⁻¹, which are compatible with HPLC separations, the DMA–cysteine complex is unstable on storage. No baseline separations are possible with anion exchange and reverse phase C₁₈ HPLC columns. The limits of detection with 50 μl injections in peak area mode are ca. 0.5 ng and 10 μg l⁻¹, respectively.     

Factorial design for optimization of experimental variables in preconcentration of copper by a chromotropic acid loaded Q-Sepharose adsorbent

An agarose-based anion exchanger (Q-Sepharose) was loaded with chromotropic acid (CTA) and used for column preconcentration and determination of copper by flame AAS. Preliminary experiments indicated that a sample pH of 5.7-6.5 is best suited for accumulation of copper and a 2.5 ml portion of a 0.02 mol l⁻¹ HCl solution can efficiently desorb the analyte from the column. An incomplete factorial design was used for optimization of five different variables that affect recovery of copper. The results indicated that ionic strength, pH and sample volume variables are the most important effects, respectively. Hence, these variables and their possible interactions were studied more carefully. In optimized conditions, the column could tolerate up to 0.18 mol l⁻¹ sodium nitrate in the matrix. A 5 ml portion of a 0.02 mol l⁻¹ CTA was sufficient for loading of a 0.5 ml column prior to preconcentration of copper from a 150 ml sample solution. Matrix ions of Ca²⁺, Mg²⁺, Na⁺ and K⁺ and potentially interfering ions of Pb²⁺, Ni²⁺, Cd²⁺, Co²⁺, Zn²⁺ and Mn²⁺ with relatively high concentrations did not have any significant effect on the recovery of the analyte. A preconcentration factor of 60 and a detection limit of 1.0 μg l⁻¹ was obtained for the determination of copper by the flame AAS method. A precision better than 2.5%, expressed as R.S.D., was also achieved. Application of the method to tap water and two different river water samples resulted in values well confirmed by direct determinations with ET-AAS.