X射线荧光光谱镶嵌制样无标测定不锈钢

样品制备是X射线荧光光谱(XRF)分析测试的首要步骤,样品制备成功与否直接影响测试结果准确性。以不锈钢为例,对尺寸不满足直接进行XRF测试的样品,利用镶嵌法进行制样,并采用XRF无标定量方法分析不锈钢中Fe、Cr、Mn、Ni、Cu、Si、Co、V、Mo等元素。利用镶嵌法研究了样品尺寸对测试结果的影响,发现以测试主次成分Fe、Cr、Ni、Mn含量为主要目标时,样品覆盖光斑面积应达到25%以上,测试元素相对误差普遍低于1.5%,微量元素(除Si外)相对误差均在5.2%以内,满足测试要求。通过无标定量法测试不锈钢标准样品,发现方法对不锈钢中主次元素Fe、Cr、Ni均可实现准确测量,相对误差不大于1.6%,微量元素中Si和Cu元素的相对误差在5.0%以内。通过镶嵌法制样无标定量测定实际样品,并与化学法对比,进一步证实XRF可实现对非标准尺寸不锈钢样品的快速测量。镶嵌法制样XRF无标定量方法亦可推广到其他合金产品分析。     

X射线荧光光谱法测定硅、磷、铬、锰、铁

以[ KNO3+NaNO3+Sr( NO3)2]为氧化剂,Na2CO3为助熔剂,Li2B4O7作熔剂,采用熔片法制备样片,建立了高碳铬铁、碳素铬铁、炉料级铬铁中硅、磷、铬、锰、铁的X射线荧光光谱分析方法,本方法采用国家标准样品和分析试样绘制了工作曲线,进行了精密度和准确度试验,其测定值与标准值相符,并有良好的精密度,完...     

X射线荧光光谱法测定不锈钢渣样中多元素含量

以Li2B4O7作熔剂,采用熔片法制样,建立了不锈钢渣样中SiO2、CaO、MgO、Al2O3、TiO2、P2O5、MnO、Fe2O3、Cr2O3的X射线荧光光谱分析方法,本方法采用国家标准样品及人工合成标准样品绘制了工作曲线,进行了精密度和准确度试验,其测定值与化学验证值相符,并有良好的精密度,完全满足生产检验要求。     

X射线荧光光谱法测定镁质耐火材料中多元素

以Li2B4O7作熔剂,采用熔片法制样,建立了镁质耐火材料中SiO2,CaO,MgO,Al2O3,P2O5,Fe2O3的X射线荧光光谱分析方法,本方法采用国家标准样品及人工合成标准样品绘制了工作曲线,进行了精密度和准确度试验,其测定值与标准值相符,并有良好的精密度,完全满足生产检验要求。     

铝质耐火材料中多元素的X射线荧光光谱分析

以Li2B4O7作熔剂,采用熔片法制样,建立了铝质耐火材料中SiO2、CaO、MgO、Al2O3、TiO2、Fe2O3的X射线荧光光谱分析方法,本方法采用国家标准样品及人工合成标准样品绘制了工作曲线,进行了精密度和准确度试验,其测定值与标准值相符,并有良好的精密度,完全满足生产检验要求。     

锰矿中多元素的X射线荧光光谱分析

以Li2B4O7作熔剂,采用熔片法制样,建立了锰矿物料中SiO2,CaO,MgO,Al2O3,TiO2,P2O5,MnO,BaO,Fe2O3的X射线荧光光谱分析方法,本方法采用国家标准样品及人工合成标准样品绘制了工作曲线,进行了精密度和准确度试验,其测定值与标准值相符,并有良好的精密度,完全满足生产检验要求。     

Characterisation of a novel Drosophila melanogaster testis specific PP1 inhibitor related to mammalian inhibitor-2: identification of the site of interaction with PP1

Paralytic shellfish poisoning (PSP) toxins are produced by certain dinoflagellate species such as Gymnodinium catenatum and Alexandrium tamarensis, during certain periods of the year influenced by several environmental factors, affecting the aquaculture industry and mainly bivalve molluscs. HPLC with fluorescence detection is a powerful analytical technique for the analysis of such toxins; several HPLC alternatives have been developed in order to improve the liquid chromatographic analysis, but due to the complexity of the sample matrix, important work has been focused recently on the clean-up of samples prior to HPLC analysis. Solid-phase extraction procedures offer advantages for this clean-up. In this work we focus on the study of three different clean-up methods prior to HPLC with fluorescence detection analysis of PSP toxin present in contaminated mussel samples; by spiking uncontaminated mussel samples with two different PSP toxin standards and by calculating the recovery values for these experiments. These recoveries must be taken into account in order to quantify the exact amount of PSP toxins present in the contaminated samples.     

Fluorescence energy-transfer cyanine heterodimers with high affinity for double-stranded DNA. II. Applications to multiplex restriction fragment sizing

Energy-transfer cyanine dyes, a thiazsole orange-thiazole-indolenine (butylTOTIN) and a thiazole orange-thiazole blue heterodimer (pentylTOTAB), form high-affinity complexes with double-stranded (ds)DNA with donor fluorescence (lambdaF(max)527 nm) quenched >90% and with acceptor fluorescence emission above 650 nm (S. C. Benson, Z. Zeng, and A. N. Glaser (1995) Anal. Biochem. 231, 247-255). After separation by agarose gel electrophoresis, bands of precomplexed dsDNA-dye restriction fragments containing 10 pg of dsDNA are readily detected with a laser-excited confocal-fluorescence gel scanner (R. A. Mathies et al. (1994) Rev. Sci. Instrum. 65, 807-812) following donor excitation at 488 nm (argon ion laser) or direct acceptor excitation at 647 nm (krypton ion laser). Accurate two-color multiplex sizing of restriction fragments is obtained with 488-nm excitation with dsDNA fragments precomplexed with thiazole orange dimer (TOTO) as unknowns (detected at 500-565 nm, green channel) and dsDNA fragments stained with the energy-transfer cyanine dyes (detected at 645-750 nm, red channel) as internal standards. There is negligible cross talk of fluorescence between the red and green channels and no significant dye migration in mixtures of prelabeled standard and unknown fragments.     

Characterization of DNA standards by capillary electrophoresis

We have used capillary electrophoresis to evaluate commercial DNA size standards and have found that it can provide an efficient assessment of size. However, the accuracy of the determination is adversely affected by anomalous migration times due to specific interactions of the DNA with the gel matrix as well as conformational differences in the DNA due to sequence heterogeneity. These anomalous migration times are strongly dependent on the choice of gel matrix. For example, the anomalous migration times that are observed in a 1 kilobase standard DNA ladder can be minimized using nongel hydroxyethylcellulose. In addition, the peak resolution can be increased and the anomalous migration can be reduced by the addition of the intercalating dye, ethidium bromide. However, in the case of the D1S80 allelic ladder, some of the DNA fragments possess nucleotide sequences which do not interact equivalently with the dye and produce irregular migration times. These measurements yield preliminary information useful in evaluating DNA size standards which may be used for a wide range of DNA diagnostic applications.     

X射线荧光光谱熔片分析的校准曲线与玻璃片质量校正

在铁合金和铁矿石的X射线荧光光谱(XRF)熔片分析中,存在着样品直接灼烧和熔融质量变化不同产生的误差,常用的稀释比校正无法校正这种误差。实验提出在固定质量(体积)的熔剂中熔入系列被测组分的氧化物制备出质量(体积)相同的玻璃片标准系列,建立X射线荧光强度与玻璃片中被测组分体积浓度的函数曲线,使用样品玻璃片质量与校准曲线玻璃片的质量比校准分析结果,即质量校正代替稀释比校正。以纯物质(SiO₂、CaCO₃、Al₂O₃和Fe₂O₃)为标准,用选定的仪器工作条件,建立了硅钙合金分析用Si、Ca、Fe、Al质量分数对荧光强度的校准曲线,其线性相关系数分别为0.9990、0.9993、0.9994、0.9995。用标准样品考察了校准曲线的准确度。t检验结果表明,当玻璃片的质量变化较大时,不使用质量校正测量结果偏差较大,正确度差。     

X射线荧光光谱法测定锌铁合金镀层铁含量的影响因素探讨

采用理学Simultix14型X射线荧光光谱仪测定锌铁合金镀层铁含量时,发现有部分试样的检测结果与国家标准推荐的方法存在较大差异,经验证,该设备不适用于低镀层量的试样和高强钢试样。实验从X射线荧光光谱仪(XRF)的检测原理、锌铁合金板的平整度、合金层结构、试样表面镀层均匀性、表面粗糙度及表面后处理等方面探讨了影响X射线荧光光谱法测定锌铁合金镀层铁含量准确性的原因。结果发现,实验用X射线荧光光谱仪的检测原理决定了该设备只适用于镀层质量大于40g/m²的试样;试样不平整时,检测结果偏大;试样的合金层结构(钢种)、镀层均匀性及表面粗糙度也会影响检测结果的准确性;而试样表面后处理(L处理)对检测结果无影响。该设备适用于镀层质量较大的平整的软钢试样。     

Alcohol and the lungs

European Union directive 90/128/EEC prescribes a specific migration limit of 0.05 mg/kg for the aliphatic diamine m-xylylenediamine (m-XDA) into food or food simultants, but there is no generally accepted method of analysis available for compliance testing with the given restriction. A method is described for the determination of m-XDA monomer in the following food simulants: distilled water, 3% (w/v) acetic acid, and 15% (v/v) ethanol. The method is appropriate for the quantitative determination of m-XDA at a minimum level of 0.020 mg/kg in these food simulants. Detection limits are in the range of 0.004 to 0.010 mg m-XDA per kilogram food simulant (depending on the type of food simulant). The method should also be applicable to other aqueous food simulants. m-XDA in aqueous simulant test samples is determined by high-performance liquid chromatography with fluorescence detection following derivatization with fluorescamine. Quantitation is relative to external standards. The identity of m-XDA may be confirmed by the presence of a second peak in the chromatograms obtained from samples derivatized with less fluorescamine or by comparison with authentic samples.     

氢化物发生-原子荧光光谱法同时测定铅锭中砷锑

国家标准方法GB/T 4103.2—2012和GB/T 4103.6—2012分别采用不同的溶样方式,用氢化物-原子荧光光谱法(HG-AFS)测定了铅及铅合金中锑和砷,流程较为繁琐。实验采用硝酸溶解样品,通过加入硫酸沉淀除去了铅基体,同时通过加热硫酸冒烟控制溶液酸度避免了锑的水解,据此建立了一次溶样,即可用HG-AFS同时测定样品中砷和锑含量。实验表明,在优化的工作条件下测定,砷和锑校准曲线的相关系数均不小于0.9997,方法检出限分别为0.0005μg/L和0.0007μg/L。干扰试验表明,样品样品中的共存元素对测定不干扰。将实验方法应用于铅锭实际样品中砷和锑的测定,检测值与国家标准方法GB/T 4103.2—2012、GB/T 4103.6—2012或IREAC-ZY-PB01检测值基本一致,砷和锑测定结果的相对标准偏差(RSD,n=6)为1.8%~2.0%。     

熔融制样-能量色散X射线荧光光谱法测定铝镁尖晶石中氧化铝、氧化镁和氧化硅

标准中针对铝镁尖晶石的分析多采用湿法或者波长色散X射线荧光光谱法。随着能量色散X射线荧光光谱仪的迅速发展,其在多个行业的元素分析中得到了广泛应用。实验通过熔融制样,利用能量色散X射线荧光光谱仪建立了铝镁尖晶石中Al₂O₃、MgO和SiO₂的测定方法。由于铝镁尖晶石无现成标准样品,实验选用合适的特优矾土、高纯镁砂等标准样品;同时,根据其生产工艺将特优矾土标准样品和高纯镁砂标准样品,以及氧化铝基准物质和高纯镁砂标准样品合成系列校准样品。固定称样量为0.5000g,样品与无水四硼酸锂(Li₂B₄O₇)熔剂的稀释比为1∶16,以4滴0.5g/mL NH₄Br溶液为脱模剂在1150℃下进行熔样的效果较好。以标准样品和校准样品绘制校准曲线,Al₂O₃、MgO、SiO₂校准曲线的均方根(RMS)分别为0.916、0.888和0.029。对镁铝砖标准样品进行精密度考察,Al₂O₃、MgO和SiO₂的相对标准偏差(RSD,n=5)分别为1.4%、0.42%和3.1%;对铝镁砖标准样品和铝镁耐火物标准样品以及铝镁尖晶石试样进行分析,Al₂O₃、MgO、SiO₂的分析结果与认定值或湿法测定值基本一致,满足生产检验要求。     

Matrix effects in the derivatization of amino acids with naphthalene dicarboxaldehyde, 9-fluorenylmethyl chloroformate and phenylisothiocyanate

Pre-column derivatizations of amino acids often present two major challenges: 1) automation, due to the multi-step manipulations for pH control, reagent addition, mixing and extraction, and 2) effect of matrices in the sample such as salts, buffers and surfactants. Both issues have been addressed in a previous publication on derivatization methods using 9-fluorenylmethyl chloroformate (FMOC) and phenylisothiocyanate (PITC). In this paper, a third method of derivatization, which has recently been developed and published, was studied to address the same issues. The derivatization reagent, naphthalene-2,3-dicarboxaldehyde (NDA), is a modification from o-phthalaldehyde (OPA) and yields more stable derivatives with high fluorescence efficiencies. An autosampler was programmed to mix amino acid samples with cyanide and NDA reagent, allow a programmed reaction time and finally inject onto the HPLC. To study sample matrix effects, amino acid samples were spiked with various concentrations of Tris-HCl, phenol, citrate, sulfosalicylic acid, sodium chloride and sodium dodecyl sulfate. The recoveries of amino acids in varied sample matrices were compared to pure amino acid standards. The matrix effects using the NDA method were similar to those using the FMOC method. Comparisons of all three methods (NDA, FMOC and PITC) are discussed and tabulated.     

Tm3+-doped tellurite glass with Yb3+ energy sensitized for broadband amplifier at 1400-1700 nm bands

A kind of novel experiment was disclosed as it possessed two bands of fluorescence emission at 1.4 and 1.6 μm, which were per-fectly complimentary to the current C band of optic communication. The fluorescence was based on energy transfer and up-conversion proc-esses between Tm3+ and Yb3+ under direct pumping of 975 nm LD. The spectra and lifetimes of Tm3+ fluorescence in the tellurite glass were described. The corresponding fluorescence characteristics and energy migration process were analyzed by the method of lifetime and inten-sity comparison. The mechanism of the up-conversion based IR fluorescence was presented upon analyzing the multi-photon pumping proc-ess. The potential advantages of Tm3+/Yb3+ co-doped tellurite glass as amplifier material were concluded.     

Trace analysis of proteins by capillary zone electrophoresis with on-column transient isotachophoretic preconcentration

The qualitative and quantitative aspects of transient isotachophoretic (ITP) sample preconcentration in the capillary zone electrophoretic analysis of protein samples have been demonstrated. By the proper selection of components of the background electrolyte and/or additives to the sample solution, two basic electrolyte arrangements have been employed. In the first, a typical isotachophoretic electrolyte system consisting of a leading and terminating electrolyte was used, and after focusing and preconcentration, the terminating electrolyte was replaced by the leading electrolyte, with the separation being continued in the zone electrophoretic mode. In the second, only one background electrolyte was used, containing a co-ion with low electrophoretic mobility, and the sample was supplemented with a salt of a highly mobile co-ion. In this case transient isotachophoretic migration of the sample ions took place at the beginning of the migration and gradually changed to the zone electrophoretic mode. Sample mixtures containing basic (positively charged) or acidic (negatively charged) proteins were examined using surface-coated fused-silica capillaries. For acidic proteins, bare silica was also tested. The isotachophoretic sample stacking permitted injection and preconcentration of sample volumes two to three orders of magnitude higher than usual in capillary zone electrophoresis. For example, up to 1 microL was injected into a 75 microns ID capillary. This approach afforded quantitative analysis of protein samples in the concentration range of 10(-7)-10(-8) M, with detection limits of approximately 10(-9) M. Furthermore, with constant sample volume injected, good reproducibility of migration times was obtained. Finally, the determination of trace components in the presence of a major sample component using transient ITP preconcentration has been demonstrated.     

能量色散X射线荧光光谱法测定大气颗粒物中无机元素应用程序的建立、评估与维护

用能量色散X射线荧光光谱法(ED-XRF)测定大气颗粒物滤膜样品中Na、Mg、Al、Si、P、S、Cl、K、Ca、Ti、V、Cr、Mn、Fe、Co、Ni、Cu、Zn、As、Pb、Sr、Ba等无机元素,不需要样品前处理,分析方法具有快速、准确的特点,方法标准已颁布实施。基于多年的应用经验,总结出建立应用程序时的要点如下:存在干扰时,应采用全谱图拟合方式对重叠谱峰进行解析,可扣除或减小干扰峰的影响,得到目标元素特征谱峰强度;为保证Na-Kα、Mg-Kα、l-Kα、Si-Kα的谱线拟合,参与拟合的谱线中应去掉位于相同或相近位置上的Lα谱线;存在干扰或相互干扰的元素如As-Pb、Fe-Co、Ti-V-Ba、Fe-Mn、Mn-Cr等,必须在相同分组条件下同时测定;滤光片的合理使用有利于提高信噪比,降低背景值,特别是对于低含量元素,背景扣除是否准确对结果影响很大;校准曲线回归后参数截距设置为0,可有效避免薄膜标样支撑膜上杂质对后续样品检测结果影响;市场上缺乏颗粒物滤膜标样时,不同分析技术、不同仪器测试结果及多家实验室间对相同颗粒物样品测试结果比对,可有效发现应用程序存在的问题。多年应用经验表明,国产模拟颗粒物滤膜标准样品和轻元素X射线荧光强度再校准样品尽快进入市场,对于有效监控荧光强度波动性,保证样品测试结果的一致性和不同实验室间相同样品测试结果的可比性具有重要意义。     

浅析在矿勘查中便携式X射线荧光分析仪的应用方法

在地质勘查仪器设备中的X-荧光分析仪,尤其是便携式 X 射线荧光分析仪在矿物质样品检测中,矿物质样品通过X 射线中的照射的作用下散射出来的 X 射线,能够快速、高效率、批量地完成分析出各种金属元素成分,便携式 X 射线荧光分析仪在我国繁重的地质矿物质分析中起到了积极的作用。本文主要对便携式 X 射线荧光分析仪的工作原理及应用进行展开分析,并列举了便携式 X 射线荧光分析仪在矿石勘查中的应用,望本论文为地质勘查工作者提供参考。     

氢化物发生-原子荧光光谱法测定铁鳞中砷和汞

建立了氢化物发生-原子荧光光谱法同时测定铁鳞中砷和汞的新方法。样品采用盐酸（1+1）分解,加入硫脲-抗坏血酸混合溶液作为还原剂和掩蔽试剂,以氢化物发生-原子荧光光谱法进行检测。详细研究了样品酸度、硫脲-抗坏血酸浓度、还原时间、硼氢化钾浓度、载流、基体效应等因素对测定结果的影响,并确定了最佳检测条件。本方法砷和汞的检出限分别为0.036 μg/g和0.010 μg/g;相对标准偏差（RSD）分别为5.1%和8.8%（n=11,As为1 μg/g,Hg为0.2 μg/g）,回收率介于95%~110%之间。