地下水中Fe的ICP-MS检测和修正方法

提出了使用电感耦合等离子体质谱法检测地下水中Fe的过程中,标准系列溶液与样品溶液由于基体不同,随雾化气流量变化时所受到的影响程度不一致,对样品中Fe的分析结果的准确性和可靠性产生不利影响。同时提出在线内标溶液含有一定浓度的Fe,并把相应的检测值带入分析结果,对低含量样品中Fe的分析结果的准确性和可靠性产生不利影响。通过实验研究,说明了使用监控样技术对这两个问题进行修正能够获得良好效果,并且相应说明了监控样的制备方法、保存条件和使用期限及对在线内标溶液的处理方法。在这个基础上,建立了新的电感耦合等离子体质谱法检测地下水中Fe的方法,重新确定了方法参数。方法的检出限(DL)达到18.9ng/mL。方法精密度(RSD)为6.11%～8.56%(n=12)。加标回收率为97.55%。     

岩石样品微量元素激光探针ICP质谱分析的内标优选

以合成玻璃标样ＮＩＳＴ６１２、岩石标样ＪＧ－１ａ及ＪＢ－３的碱熔玻璃为代表，分别选用各种样品中主要元素或其次丰度同位素为内标，对比了３０个微量元素的激光针针ＩＣＰ质谱的分析精度，进而对内标进行优选。实验结果表明，不同样品类型所选择的内标稍有不同；不同质量和性质的元素对内标的选择无明显依赖关系，选用样品中基体元素为内标可以获得较好的分析精度；对ＪＧ－１ａ花岗岩类样品，选＾２９Ｓｉ，＾３０Ｓｉ，＾４３     

碘离子溶液标准物质的研制及不确定度评定

建立碘离子溶液标准物质的制备方法及不确定度评定模型。采用质量-容量法制备特性量值为10μg/m L的碘离子溶液标准物质,该标准物质以高纯碘化钾为原料,经IC、ICP和ICP-MS 3种方法分析检测扣除其杂质,并且通过干燥减重法扣除其水分含量,精确测定碘化钾的纯度。制备的碘离子溶液标准物质均匀性和稳定性良好,定值结果的相对扩展不确定度为U=2%(k=2),有效期限为12个月,与同类标准样品GSB 04-2834-2011进行比对分析,结果显示,在规定的不确定度范围内量值具有一致性。该碘离子溶液标准物质可用于环境水质、食品安全等领域的安全检测及相应分析方法的确认与评价。     

微波消解-石墨炉原子吸收光谱法测定蔬菜中痕量钼

建立了微波消解-石墨炉原子吸收光谱法测定蔬菜样品中的痕量钼。通过密闭高压、微波消解样品来制备样品溶液,研究了不同基体改进剂及其用量对吸光度的影响;采用氘灯背景扣除,313.3 nm作为钼的测定波长,3μL 1 g·L~(-1)磷酸二氢铵为基体改进剂,灰化温度为1000℃;原子化温度为2800℃。在该实验条件下,方法的线性范围为0~200μg·L~(-1),相关系数r=0.9997,检出限为3.6μg·L~(-1),测定样品的相对偏差为0.50~2.1%,回收率为92.8%~102.4%。该法灵敏快速,准确度高,适用于蔬菜等植物样品中痕量钼的测定。     

高温过饱和硝酸铵溶液的爆炸危险性分析

为了研究过饱和硝酸铵（AN）溶液的爆炸特性,采用联合国隔板试验研究了不同状态过饱和AN溶液的爆轰特性。结果显示:对于常温过饱和AN溶液,当w(水)≤4%时,在联合国隔板试验1(a)中,试验后钢管完全破裂或验证板发生穿孔,即样品能传播爆轰;在联合国隔板试验2(a)中,试验后钢管部分撕裂或保持完好,验证板轻微变形,有大量样品残余,显示样品对爆炸冲击波刺激不敏感。对于140 ℃过饱和AN溶液,在联合国隔板试验2(a)中,当w(水)≤3.0%时,试验后样品钢管完全破碎,验证板穿孔,即样品在该试验条件下对爆炸冲击波作用敏感,表明过饱和AN溶液具有爆炸性,且温度升高会显著提高其爆炸危险性。     

顶空气相色谱法测定紫草素中的乙醇残留

建立一种用于测定紫草素中的乙醇含量的顶空气相色谱法,采用异丙醇为内标,内标曲线法进行测定.对溶剂、色谱柱温度、样品的平衡温度、样品的平衡时间等因素进行考察,筛选出最合适的条件.对分析方法的专属性、线性、重复性、回收率、溶液稳定性、检测限、定量限进行验证.结果表明,本法专属性良好,在0.1mg·mL-1～2mg·mL-1...     

ICP-OES内标法测定氧化铝基催化剂中的钯含量

建立了ICP-OES内标法测定氧化铝基催化剂中钯含量的分析方法,以钇为内标物,通过选择合适的仪器操作条件,在简化实验操作的同时,有效避免样品基体对分析结果的干扰。方法的检出限为0.01mg/L,样品的加标回收率99%-101%,相对标准偏差1%。完全满足氧化铝基催化剂中钯的分析要求。     

基于钴内标X射线荧光光谱分析法在铁矿石分析中的应用研究

本文主要就钴内标X射线光谱分析方法、工作曲线、标样制作、精密度和准确度、钴玻璃的熔融条件及特殊样品处理方式进行阐述,讲述用钴内标X射线方法分析铁矿石主、次元素的优点与注意事项。     

端视ICP-AES测定有机肥中有害元素

用配置C ID固态检测器的端视ICP按现行国标的样品处理方法,测定有机肥中有害元素Pb、Cd、Cr、As、Hg。方法确定了选择检测谱线和背景扣除点的原则。样品加标标准相对偏差(RSD)在1.2%~4.5%之间,方法检出限(DL)为2.4~8.5μg.L-1。     

ICP-AES内标法测定不锈钢中Cr、Ni、Cu、Mn

本文采用王水溶样,酸化水稀释,ICP-AES内标法快速测定不锈钢中Cr、Ni、Cu、Mn的含量。研究了溶液的酸度、基体浓度以及内标线选择,确定了试样分析的最佳工作条件。方法回收率99～115％,RSD2.6—6.3％。标准参考物的分析结果与推荐值基本一致。     

Background values for evaluation of heavy metal contamination in sediments

The contamination of sediments can be evaluated from comparison of the current concentration with the estimated background value. Although it is known that grain size affects background concentrations, there have been difficulties in evaluating this effect. The specific surface area of sediments, which can be calculated from the grain size distribution, is introduced as a property index for correlation of background values. The results show that for sandy-to-sandy silt sediments, the background values of metals are expressed in terms of fines content, which can be correlated with the corresponding specific surface area. However, for silty clay or clayey silt sediments, which would have a high metal retention capacity, the level of the background may be constrained by the relatively low concentrations of metals in seawater. Finally, background levels of Zn, Cu and Pb are presented.     

一种自适应噪声抵消系统的仿真与设计

自适应噪声抵消系统是基于自适应滤波原理的一种扩展,它能从被噪声干扰的环境中检测和提取有用信号,抑制或衰减噪声干扰,提高信号传递和接收的信噪比质量。研究常用噪声消除算法,并仿真验证系统设计和所选自适应算法的可行性,最后应用DSP技术设计一个自适应噪声抵消系统,使其能消除含噪语音信号中的背景噪声,达到提高语音信号质量的目的。     

Development of surfactant assisted spectrophotometric method for determination of selenium in waste water samples

A new, simple and highly selective method for spectrophotometric determination of selenium in waste water samples is described. Selenium(IV) oxidizes I(-) ions into I(2) which subsequently reacts with excess of I(-) ion in the acidic media to give tri-iodide ions (I(3)(-)), and it further reacts with cetylpyridinium cation (CP(+)) to give a violet colored species. The value of molar absorptivity of the ion-associate species in terms of selenium is 1.80 x 10(4) L mol(-1)cm(-1) at lambda(max) 510 nm. The detection limit of the method is 10 ng mL(-1) Se. The calibration curve is linear over 50-1000 ng mL(-1) Se with slope, intercept and co-relation coefficient of 0.23, -4.0 x 10(-4) and +0.99, respectively. None of the tested diverse ions interfered in the present method. The method has been tested for the determination of selenium in waste water samples.     

测定叶绿素a方法的改进

本文对水体中叶绿素a的国家规范分析方法进行改进。结果表明,方法经改进后,减少了前处理过程中样品的损失,提高了分析的精密度,避免了丙酮对人体的伤害。     

Determination of Lead Ions by an Optical Sensor Based on 2-Amino-Cyclopentene-1-Dithiocarboxylic Acid

A new spectrophotometric sensor for the determination of lead at trace level was developed using chemically immobilized 2-amino-cyclopentene-l-dithiocarboxylic acid (ACDA) on a triacetylcellulose. The sensor provided a wide concentration range of 1.0 x 10^-6 to 5.0 x 10^-1 M Pb(II) with a limit of detection of 6.9 X 10^-7 M Pb(II). The method also showed a reproducible result with relative standard deviation of less than 3.5% and response time of the optode was 10 min. Interference studies showed that Co(II) and Ni(II) ions interfered during the determination. The interference of potential interfering ions could be eliminated using a simple extraction procedure. The method was successfully used to determination of Pb(II) ions in reference alloy, water, and waste water samples with satisfactory results.     

北台石灰石矿硐室爆破几个设计问题的探讨

首先介绍了北台石灰石矿硐室爆破的主要目的和要求;然后详细论述了爆破设计和施工,包括药包布置原则、爆破参数确定、炸药品种选择、装药结构和堵塞、起爆网路和起爆顺序以及安全距离和安全防护措施,并对几个设计问题进行了探讨;最后,作者在多次硐室爆破实践经验的基础上建议,药包的最小抵抗线可扣除风化岩层的厚度,根据这个最小抵抗线值来计算药量。     

Selective removal of Pb(II), Cd(II), and Zn(II) ions from waters by an inorganic exchanger Zr(HPO3S)2

The present study reported synthesis of a new inorganic exchanger, i.e., zirconium hydrogen monothiophosphate [Zr(HPO₃S)₂, denoted ZrPS] and its selective sorption toward Pb(II), Cd(II) and Zn(II) ions. ZrPS sorption toward all the three metals is dependent upon solution pH due to the ion-exchange nature. As compared to another inorganic exchanger zirconium phosphate [Zr(HPO₄)₂, denoted ZrP], ZrPS exhibits highly selective sorption toward these toxic metals from the background of calcium ions at great levels. Such sorption preference is mainly attributed to the presence of –SH group in ZrPS, as further demonstrated by FT-IR analysis and XPS study. Moreover, ZrPS particles preloaded with heavy metals could be efficiently regenerated with 6 M HCl for multiple use without any noticeable capacity loss. All the experimental results indicated that ZrPS is a promising sorbent for enhanced heavy metals removal from contaminated water.     

Design, fabrication and performance evaluation of a 22-channel direct reading atomic emission spectrometer using inductively coupled plasma as a source of excitation

The indigenous design, fabrication and performance evaluation of a polychromator, using inductively coupled plasma (ICP) as a source of excitation, are described. A concave holographic grating is used as the dispersing element and a Paschen — Runge mount is chosen to focus the spectra over a wide range along the Rowland circle. Twenty-two exit slits, mounted along the circle, precisely correspond to the wavelengths used for determination of up to twenty elements present in the plasma. Radiations emerging from the exit slits are detected by photomultiplier tubes placed behind them. The photomultiplier signal is recorded by an electronic system consisting of an integrator and a PC-based data acquisition system. The performance of the spectrometer has been evaluated with an ICP excitation source. Synthetic standards in deionized water containing a mixture of twenty impurities have been analysed. Typical determination limits observed for elements range from sub-ppm to ppm levels. All the elements present as impurities can be detected simultaneously. It is also observed that each element has a different emitting region in the ICP flame for which the maximum signal to the background is obtained. The determination limits obtained corresponding to these zones are the lowest. A study of the sensitive emitting zones for several elements has been carried out and the results are demonstrated by photographs of the ICP flame. The study will help in achieving the minimum value of determination limit for an impurity element.     

Universal approach for selective trace metal determinations via sequential injection-bead injection-lab-on-valve using renewable hydrophobic bead surfaces as reagent carriers

A new concept is presented for selective and sensitive determination of trace metals via electrothermal atomic absorption spectrometry based on the principle of bead injection (BI) with renewable reversed-phase surfaces in a sequential injection-lab-on-valve (SI-LOV) mode. The methodology involves the use of poly(styrene-divinylbenzene) beads containing pendant octadecyl moieties (C18-PS/DVB), which are preimpregnated with a selective organic metal chelating agent prior to the automatic manipulation of the beads in the microbore conduits of the LOV unit. By adapting this approach, the immobilization of the most suitable chelating agent can be effected irrespective of the kinetics involved, optimal reaction conditions can be used for implementing the chelating reaction of the target metal analyte with the immobilized re-agent, and an added degree of freedom is offered in selecting the most favorable elution mode in order to attain the highest sensitivity. The potential of the SI-BI-LOV scheme is demonstrated by taking Cr(VI) as a model analyte, using a 1,5-diphenylcarbazide (DPC)-loaded bead column as the active microzone. As this reaction requires the use of high acidity, it is also shown that the bead material exhibits excellent chemical stability at low pH values. On-line pH sample adjustment prevents alteration of the original distribution of chromium species while ensuring fast rates for the DPC-Cr(VI) reaction. The proposed procedure was successfully applied to the determination of trace levels of Cr(VI) in natural waters containing high levels of dissolved salts (such as seawater and hard tap water) without requiring any dilution step. Method validation was performed by determination of total chromium in an NIST standard reference material (NIST 1640, natural water) after Cr(III) oxidation, and the results were in good agreement with the certified value.     

Complexing of heavy metals with DNA and new bioaffinity method of their determination based on amperometric DNA-based biosensor

The immobilized single-stranded DNA (ssIDNA) has been found to be a very effective biospecific analytical reagent when used in a newly developed bioaffinity method of the determination of heavy metals based on the amperometric DNA-based biosensor. This has been concluded from the comparative study of the complexing of heavy metals with double-stranded DNA, single-stranded DNA, and ssIDNA, using Fe(III) and Cu(II) as a model (metal/nucleotide ratio and stability constants are maximum for ssIDNA), from the study of adsorption of Fe(III), Cu(II), Pb(II), and Cd(II) on nitrocellulose membranes, containing single-stranded DNA, and from the determination of their binding constants with ssIDNA. According to these data, the chosen heavy metals can be lined up in a series of binding strengths with ssIDNA: Cu(II) > Pb(II) > Fe(III) > Cd(II). The method of the determination of heavy metals is based on biospecific preconcentration of metal ions on the biosensor followed by the destruction of DNA-metal complexes with ethylenediaminetetraacetate and voltammogram recording has been proposed. The lower detection limits are 4.0 x 10(-11), 1.0 x 10(-10), 1.0 x 10(-9), and 5.0 x 10(-9) M for Cu(II), Pb(II), Cd(II), and Fe(III), respectively. The heavy metals have been assayed in multicomponent environmental and biological systems such as natural and drinking water, milk, and blood serum samples.