泡塑富集-石墨炉原子吸收光谱法测定地质样品中微量铊

采用HF-HClO4-HNO3溶解样品,泡沫塑料富集-石墨炉原子吸收光谱法测定岩石、土壤、水系沉积物等地质样品中微量铊。以抗坏血酸为基体改进剂,Fe3+加入量选择200mg,灰化温度为600℃,原子化温度为1600℃。方法用于测定国家一级标准物质,结果与标准值基本一致。方法精密度(RSD,n=8)为2.73%—3.93%,回收率为96.7%—101.3%,检出限可达0.060μg/g。     

高基质进样-电感耦合等离子体质谱法测定职业接触人员血中铊

职业接触人员血中铊浓度可反映其体内暴露的信息。因此,建立血中铊浓度的检测方法具有非常重要的意义。目前,国内血中铊检测没有国家标准方法,国内外文献报道的方法均存在一定缺点。为了获得准确的职业接触人员血中铊浓度,建立了高基质进样（HMI）-电感耦合等离子体质谱（ICP-MS）测定职业接触人员血中铊含量的方法。通过对等离子体模式和前处理方法进行了选择,0.20 mL血样用0.1% Triton X-100+0.5%硝酸混合溶液处理后,采用在线加入内标的方式对铊含量进行了检测。在最佳的分析条件下,205Tl在0.02～4.00 μg·L-1范围内线性关系良好,Y=0.010 33X+0.000 12,相关系数（R）为0.999 9。最低检出限（detection limit,DL）为0.005 μg·L-1,最低定量限（quantification limit,QL）为0.02 μg·L-1;当取样量为0.20 mL,定容体积为5.00 mL时（血样25倍稀释）,方法检出限（MDL）为0.12 μg·L-1,方法定量下限（MQL）为0.42 μg·L-1,测定范围为0.42～100 μg·L-1。在全血样品中添加水平为2.50,15.0和75.0 μg·L-1时的平均回收率为92.7%～103.8%。每个样品重复测定7次,批内精密度（RSDs of in-batch）为1.71%～2.81%,批间精密度（RSDs of interbatch）为2.84%～4.77%,表明,该方法的准确度及精密度良好。连续监测50个样品（包括标准溶液、质量控制样品和全血样品）,内标元素209Bi的信号变化为+7.7%,表明方法稳定性较好。将建立的新方法用于30份职业接触人员全血的分析检测,其中4份血样的铊含量大于方法检出限,但低于方法定量下限,其余26份血样均低于方法检出限,且30份全血样品中铊含量均在平均背景范围内。结果表明30位职业接触人员铊内暴露水平很低,其工作场所铊对人体基本无潜在的健康影响。该方法简单快速、准确度高、稳定性好,适用于实际样品的大批量检测。     

LEFC-2006在水质铊监测中的应用研究

铊作为剧毒的重金属元素,具有较强的蓄积性、潜伏性和迁移性,含铊矿床的开采及其工业三废的大量排放,都可导致铊进入地表环境,参与到土壤圈、水圈、大气圈、生物圈物质循环,并逐步在土壤和水体中富集,破坏生态环境,最终会通过食物链危及人体健康。近年,水质铊污染突发事件时有发生,水环境铊的分析技术也成为铊分析技术研究的热点,但多集中在实验室分析方法的改进方面,水质铊在线监测分析方面的研究甚少。而实验室分析方法在运输、保存过程中难免有污染、损失等;且在数据时效性上也导致了一定的滞后,很难应用于水体铊的应急监测分析,从而影响了污染事故的分析和处置,成为处置污染事故的最大瓶颈。为了快速、准确响应水质铊现场监测,开展的水质在线监测技术研究对水质铊元素监测具有重要的应用意义,可以实现水体铊污染的监测与预警,进而有效降低因环境铊污染引起的铊中毒的风险。建立了一种基于三电极方法原理的水质铊监测新技术。该方法所用仪器小型、便携、低成本,不仅可用于铊污染事故应急现场监测,还可以用于污染源监管、地表水风险预警自动监测。本文就仪器检出限、正确度、精密度、方法比对、现场应用等各项性能指标进行了验证。实验表明,该技术用于测定水质铊的方法检出限为0.02 μg·L-1,与ICP-MS仪的检出限一致;用于测定铊标准溶液的相对误差范围为-5.5%~2.9%;测定实际水样的相对标准偏差范围为0.60%~6.2%;其加标回收率达到101%~127%。当水样含量在0.08 μg·L-1以上,该方法在现场应急监测比对中,与实验室ICP-MS法具有可比性,表明该技术具有很好的适用性。     

超声浸提-No Gas-电感耦合等离子体质谱法测定工作场所空气中铊及其化合物

铊（Thallium,Tl）是一种有毒的金属元素,主要用于半导体、电子设备、农药和灭鼠剂的生产,会对职业人群的身体健康造成潜在的威胁,工作场所空气中铊及其化合物浓度的测定对保证职业人群的健康具有重要意义。虽然工作场所空气中痕量铊的毒性高于其他有毒金属元素,但对其研究却很少。目前工作场所空气中铊及其化合物浓度检测方法主要是原子吸收光谱法（AAS）,但该方法有不足之处。建立了超声浸提-No Gas-电感耦合等离子体质谱（ICP-MS）测定工作场所空气中铊及其化合物（以205Tl计）的新方法。在采样点,按照GBZ 159-2004方法用0.8 μm孔径的微孔滤膜对工作场所空气进行短时间采样。检测过程中,考察了不同超声浸提条件对测定结果的影响,并对质谱干扰及消除进行了分析。最终优化的实验条件为3%硝酸在室温条件下对采集的滤膜样品进行超声浸提10 min,采用No Gas模式对工作场所空气中铊及其化合物（以205Tl计）进行ICP-MS分析。在该实验条件下得出铊及其化合物在0.087～80 ng·mL-1浓度范围内呈现良好的线性关系（Y=0.009 2X-0.001 8,R=0.999 9）;检出限为0.026 ng·mL-1,当采样体积为75 L时,最低检出浓度为0.001 7 μg·m-3,最低定量浓度为0.005 7 μg·m-3。用质控样品（滤膜中铊质量控制样品ZK147和ZK148）验证了本方法的精密度和准确度,结果显示测定值与参考值之间无显著性差异,相对标准偏差（RSD）为0.77%和0.86%。用加标法（3倍于滤膜中铊含量的常见干扰元素）对建立的新方法进行干扰分析,回收率在97.2%～106.7%之间,表明本法抗干扰能力较强。用本法与国标方法《工作场所空气有毒物质测定 第25部分：铊及其化合物》（GBZ/T 300.25-2017）溶剂洗脱-石墨炉原子吸收光谱法相比较,10个实际样品的测定结果基本一致。相对于现行国标方法,该方法具有操作简单、检出限低、线性范围宽和准确度高的优点,能够满足实际工作场所空气中铊及其化合物的准确、快速、痕量及高通量测定需求。该方法有望成为工作场所空气中铊及其化合物测定的新方法,可更高效地为特定职业人群健康监护提供参考和依据。     

Chromium localization in plant tissues of Lycopersicum esculentum Mill using ICP-MS and ion microscopy (SIMS)

High-resolution imaging secondary ion mass spectrometry (HRI-SIMS) in combination with inductively coupled plasma mass spectrometry (ICP-MS) were utilised to determine specific sites of chromium concentration in tomato plant tissues (roots, stems and leaves). The tissues were obtained from plants grown for 2 months in hydroponic conditions with Cr added in a form chromium salt (CrCl₃·6H₂O) to concentrations of 25 and 50 mg/L. The chemical fixation procedure used permit to localize only insoluble or strongly bound Cr components in tomato plant tissue. In this work no quantitative SIMS analysis was made. HRI-SIMS analysis revealed that the transport of chromium is restricted to the vascular system of roots, stems and leaves. No Cr was detected in epidermis, palisade parenchyma and spongy parenchyma cells of the leaves. The SIMS-300 spectra obtained from the tissues confirm the HRI-SIMS observations. The roots, and especially walls of xylem vessels, were determined as the principal site of chromium accumulation in tomato plants.     

固相萃取-高效液相色谱法测定烟叶中吡虫啉农药残留量

建立了固相萃取-高校液相色谱法测定烟叶中吡虫啉农药残留量的方法。样品用乙腈提取,弗罗里硅土固相萃取柱净化.梯度洗脱方式分离,DAD二极管阵列检测器检测。吡虫啉加标回收率为87.83%—94.80%,相对标准偏差为1.64%,检出限为0.01μg/g。该方法灵敏、准确,适用烟草中吡虫啉农药残留的分析。     

可见/近红外光谱分析技术鉴别转基因番茄叶

用可见/近红外光谱（Vis-NIR spectrum）漫反射方式对转基因番茄叶和非转基因番茄叶进行了快速、无损的定性分析。实验共对68个样品（转基因38个,非转基因30个）进行分类,用TQ 6.2.1光谱分析软件中集成的判别分析（Discriminant analysis）和偏最小二乘回归法（PLS）建立校正和预测模型。研究对比了不同光谱预处理方法（微分处理和多元散射校正（MSC））对分类结果的影响。实验结果发现用判别分析较最小二乘法判别结果较好,用InGaAs检测器获得的光谱经MSC后的分类结果最好,分类正确率为89.7％（转基因番茄叶86.8％,非转基因番茄叶93.3％）。结果表明VIS-NIR可以作为一种快速的无损检测方法鉴别转基因和非转基因番茄叶。     

高光谱成像技术检测高温障碍胁迫下番茄叶片色差的研究

提出了利用可见/近红外高光谱成像技术检测高温障碍胁迫下番茄叶片色差的方法。首先采集380~1 023 nm波段范围内60个高温障碍胁迫和60个健康番茄叶片的高光谱图像,同时获取全部叶片的色差值(L*, a*和b*),然后提取所有样本的高光谱图像中感兴趣区域(region of interest, ROI)的光谱反射率值。基于不同预处理方法建立偏最小二乘(partial least squares, PLS)预测模型,再利用连续投影算法(successive projections algorithm, SPA)提取特征波长并建立SPA-PLS预测模型。最后分别基于全波段和特征波段建立偏最小二乘-判别分析(partial least squares-discriminant analysis, PLS-DA)模型。结果显示,全波段中基于原始光谱信息建立的模型效果最好,3个色差值的预测集决定系数(determination coefficient, R2)分别是0.818,0.109和0.896;基于特征波长建立的模型预测集R2分别是0.591,0.244和0.673;所有模型预测集的总体识别率均大于77.50%。结果表明,可见/近红外高光谱成像技术检测番茄叶片色差值(L*和b*)和识别高温障碍样本是可行的。     

基于高光谱的番茄叶片斑潜蝇虫害检测

番茄植株在生长过程中受病虫害的侵染,将导致番茄减产和种植户的经济效益降低,该研究用高光谱技术结合化学计量学方法,实现了番茄叶片斑潜蝇虫害的快速识别。搭建了简易的高光谱成像系统,包括光源单元、高光谱图像采集单元和数据处理单元,用该系统获取番茄叶片的高光谱图像,对高光谱图像进行校准,并从每一幅图像中提取光谱信息。分别采用了光谱角匹配(SAM)分析方法和光谱红边参数判别分析(DA)方法识别番茄叶片斑潜蝇虫害。在SAM分析中,对高光谱数据进行了归一化预处理,以消除多余信息,增加样品之间的差异。比较了以不同番茄叶片样品的反射光谱作为测试光谱时,虫害识别效果的差异,当以受到斑潜蝇侵染的番茄叶片的平均反射光谱作为测试光谱时,虫害识别的正确率较高,达到96.5%。在光谱红边参数判别分析中,从光谱数据中提取了红边位置、红边振幅、最小振幅、红边面积、红谷位置和红边振幅/最小振幅6组红边信息,利用判别分析方法建立番茄叶片斑潜蝇虫害的判别模型,比较了距离判别、Fisher判别、Bayes判别分析方法的判别效果,使用距离判别分析建模的判别正确率最低,判别正确率为88.0%,使用Fisher判别分析建模的效果最佳,判别正确率为96.0%。研究结果表明,采用高光谱技术识别番茄叶片斑潜蝇虫害具有可行性。     

Mixture Design Optimization of an Analytical Procedure for Iron Extraction and Determination From Cassava Leaves by Slurry Sampling Flame Atomic Absorption Spectrometry

ABSTRACT

This paper applies statistical simplex-centroid design to mixture modeling for optimization of the liquid phase composition of cassava slurry leaves in the development of an analytical procedure for iron determination using flame atomic absorption spectrometry (FAAS). This procedure is based on a slurry formation from powdered cassava leaves and a liquid mixture composed of HNO₃, HCl, and H₂O₂ after an ultrasonication process. A quadratic model fitted to the analytical response shows the existence of an experimental region, characterized by low proportions of H₂O₂, for which higher responses are obtained. The proposed procedure allows the determination of iron in the cassava leaves with a detection limit of 1.1 µg g^?1. The precision expressed as relative standard deviation (%RSD, n = 10) was 1.5% for iron concentrations of 25 µg g^?1. The developed procedure was validated by the comparison of results obtained from the application of the digestion procedure and the analysis of certified reference materials: Apple leaves (NIST 1515). Results found were in agreement with the certified values. The proposed method was applied for the determination of iron in four samples of cassava leaves acquired in markets of Feira de Santana City, Brazil. The concentration of iron found in the cassava leaves varied from 250.8 ± 0.7 to 283.4 ± 0.7 µg g^?1.     

微波消解FAAS测定新疆出口番茄酱中的微量元素

采用微波消解试样,FAAS法对新疆4个厂家出口番茄酱中的微量元素进行测定.经过回收率和精密度试验,结果表明:6种微量元素的相对标准偏差在0.23%-2.10%;回收率在94.8%-104.5%;并以番茄叶的标准样品(ESP-1)进行比较测定,标准样品的测定值与参考值基本一致,该方法获得了满意的精密度和准确度.     

应用高光谱图像光谱和纹理特征的番茄早疫病早期检测研究

提出了应用光谱和纹理特征的高光谱成像技术早期检测番茄叶片早疫病的方法。利用高光谱图像采集系统获取380～1 030 nm范围内71个染病和88个健康番茄叶片的高光谱图像,同时采用主成分分析法(PCA)对高光谱图像进行处理。选取染病和健康叶片感兴趣区域(region of interest, ROI)的光谱反射率值,同时分别从前8个主成分的每幅主成分图像的ROI中提取对比度(Contrast)、 相关性(Correlation)、 熵(Entropy)和同质性(Homogeneity)4个灰度共生矩阵的纹理特征值,再通过PCA和连续投影算法(SPA)结合最小二乘支持向量机(LS-SVM)构建番茄叶片早疫病的早期鉴别模型。建立的6个模型中,采用光谱反射率值的LS-SVM模型对番茄叶片早疫病的识别率最高,达到100%。结果表明,应用高光谱成像技术检测番茄叶片早疫病是可行的。     

Effect of thallium on magnetic susceptibility of arsenic sulphides

Magnetic susceptibility was studied of samples of Tl_2xAs₂S_3+x and Tl_2xAs₂S₄ series where 0x1 differing in abundance of bonds in structural units. Absolute value of specific magnetic susceptibility decreases with increasing thallium content. Separation of susceptibility in dia- and paramagnetic parts made it possible to refer to the correlation of absorption edge position and paramagnetic susceptibility component.     

温室番茄缺素叶片偏振反射特征分析

为提高番茄植株营养胁迫定量分析模型的精度,探究偏振检测在植物单叶尺度进行无损检测的优势,利用自行研制的偏振反射光谱系统检测不同生长期温室番茄缺素叶片偏振反射特征。对影响番茄单叶偏振反射的主要因素：方位角、入射天顶角、探测天顶角、光源偏振片起偏角度、探测器偏振片起偏角度进行了讨论,通过正交试验的极差分析获取光谱仪各测量角度参数的优水平,并通过实验进一步验证,最终分析得到偏振光谱系统检测番茄缺素叶片的角度组合及主次排序为：入射天顶角60°、光源起偏角度0°、探测器起偏角度45°、探测天顶角45°、方位角180°,在此基础上对不同生长期的缺氮、缺磷、缺钾叶片以及不同缺素程度的叶片进行分析比较,结果显示偏振反射比随番茄叶片的生长周期呈现正相关关系,缺素和营养过量均能导致偏振反射比的下降,偏振反射比在结果期和采收期的降幅较为明显。对于偏振反射光谱在植物单叶尺度营养快速检测的深入研究具有一定的理论和实践意义。     

Rotatory dispersion in hydrated cobaltous salts

Chemical shifts are recorded for the thallium resonance of ²⁰³Tl and ²⁰⁵Tl in a number of thallium compounds in the solid state and in aqueous solutions. Different chemical shifts are found for Tl⁺, TlCl₄′ and TlCl₆…'. Solid Tl₂Cl₃ shows two thallium resonances with intensities in the ratio 3 : 1, consistent with the formula Tl₃(TlCl₆). Hydrated thallic chloride in the solid state shows three thallium resonances which may be due to the presence of Tl(H₂O) _x ⁺⁺⁺, TlCl₄′ and TlCl₆…'. The chemical shifts of the thallium resonance in aqueous thallic chloride and bromide solutions in the presence of added halides are consistent with the stepwise formation of complex ions. The second moments of the resonances of the two thallium isotopes in solid compounds shows that there is spin-spin coupling between the thallium isotopes, and a weak coupling in some cases between thallium nuclei and the nuclei of anions.     

Preparation, crystal structure, and electrical properties of thallium monosulfide in the vicinity of high-temperature phase transitions

Single crystals of thallium monosulfide TlS with excess sulfur (4 at. %) are grown. The existence of monoclinic (of the TlGaSe₂ type), tetragonal ordered (of the TlS type), and subtetragonal phases of thallium monosulfide is revealed using x-ray powder diffraction. The temperature dependences of the electrical conductivity and permittivity of thallium monosulfide single crystals indicate that, in the temperature range 401–411 K, these crystals undergo a phase transition to a state with superionic conduction.     

High pressure studies on the electrical resistivity of Ge–Te–Tl glasses

The variation of electrical resistivity in the system of glasses Ge₁₇Te_83?xTl_x, with (1≤x≤13), has been studied as a function of high pressure for pressures up to 10 GPa. It is found that the normalized electrical resistivity decreases continuously with the increase in pressure and shows a sudden drop at a particular pressure (transition pressure), indicating the presence of a transition from semiconductor to near-metallic at these pressures which are in the range 3.0–5.0 GPa. This transition pressure is seen to decrease with the increase in the percentage content of thallium due to increasing metallicity of the thallium. The transition is reversible under application of pressure and X-ray diffraction of samples recovered after pressurization show that they remain amorphous after undergoing a pressurization decompression cycle.     

Flow injection determination of metoclopramide based on KMnO4—HCHO chemiluminescence in a micellar medium

A novel flow injection chemiluminescence (CL) analysis method for the determination of metoclopramide in the presence of sodium dodecyl sulfonate (SDS) surfactant micelles is described. This method is based on the luminescent properties of the KMnO₄-HCHO-metoclopramide in acid medium sensitized by SDS. The optimized experimental conditions were evaluated and the possible mechanism was discussed. The CL increase is linearly related to the concentration of metoclopramide in the range 0-80.0 μg/ml with a detection limit of 31.3 ng/mL (S/N=3).The relative standard deviation for 20.0 μg/ml samples was 2.6% (n=11). The proposed method has been successfully applied to the determination of metoclopramide in tablets.     

程序控温石墨消解-氢化物原子荧光光谱法测定植物中痕量硒

探讨了硒测定的几种预处理方法,采用一种程序控温的石墨消解系统来消化处理柑橘叶、茶叶、灌木叶、圆白菜、大米五种代表性的植物标准样品。详细研究了这类植物样品前处理方法中消解液用量、消解温度以及消解时间对植物样品中硒提取效果的影响;优化了氢化物发生-原子荧光光谱法(HG-AFS)的仪器参数条件;在氢化物反应条件中重点考察了还原剂KBH₄浓度和酸度(HCl)对硒测定的影响,不仅考虑了载流HCl浓度的影响,还从样品HCl浓度就酸度对硒测定影响作了进一步细致研究,从而建立了石墨消解-氢化物发生原子荧光光谱法测定这类植物样中痕量硒的最佳测定方法。结果显示：该方法中硒加标回收率在87.1%～106.2%,检出限0.018 μg·L-1,精密度RSD＜6.0 %,标准物质的测试结果与参考值均相吻合;在0～10 μg·L-1低标范围内和在0～100 μg·L-1 高标范围内,荧光值与硒浓度均呈线性相关,相关系数分别为r=0.999 9和=0.999 7。因此该方法具有线性范围宽、灵敏度高、检出限低,稳定性好的显著特点,尤其适合如柑橘叶、茶叶、灌木叶、圆白菜、大米等这类批量植物样品硒的痕量分析,且该方法操作简便安全,实用性强,仪器成本低,所用试剂毒性小,可作为一般实验室的常规分析方法。     

Effect of a fullerene C60 addition on the strength properties of nanocrystalline copper and aluminum under shock-wave loading

The Hugoniot elastic limit and the spall strength of aluminum and copper samples pressed from a mixture of a metallic powder and 2–5 wt % C₆₀ fullerene powder are measured under a shock loading pressure up to 6 GPa and a strain rate of 10⁵ s^?1 by recording and analyzing full wave profiles using a VISAR laser interferometer. It is shown that a 5% C₆₀ fullerene addition to an initial aluminum sample leads to an increase in its Hugoniot elastic limit by an order of magnitude. Mixture copper samples with 2% fullerene also exhibit a multiple increase in the elastic limit as compared to commercial-grade copper. The elastic limits calculated from the wave profiles are 0.82–1.56 GPa for aluminum samples and 1.35–3.46 GPa for copper samples depending on the sample porosity. The spall strength of both aluminum and copper samples with fullerene additions decreases approximately threefold because of the effect of high-hardness fullerene particles, which serve as tensile stress concentrators in a material under dynamic fracture.