Enhancing chemical analysis with signal derivatization using simple available software packages

Derivative techniques for analytical signal processing are useful for solving some noise and signal resolution problems in various fields of study such as titrimetry, spectrophotometry, chromatography and electrochemistry. The broad use of these techniques, however, is often limited by costly inflexible built-in software packages in commercial analytical instruments. We propose here the application of commercial simple software packages such as Microsoft® Excel and Microcal Origin for signal smoothing and fitting, and for obtaining derivative analytical signals in batch and flow-based analyses, including potentiometric titration, spectrophotometry, chromatography, voltammetry and sequential injection analysis (SIA). The worldwide (especially Excel) software packages are easy-to-use for less experienced users and have also capabilities for advanced users, and therefore employing such packages can result in expansion of useful derivative techniques. We demonstrate application of the available package-aided derivative capabilities for enhancing some chemical analyses, including potentiometric acid–base titration, Bradford assay of protein, chromatographic separation of ajmaline and reserpine and anodic stripping voltammetry of copper. The derivative signals from smoothed and fitted curves offer better accuracy and precision, even for non-resolving peaks and tailing peaks. In some cases, the optimization of experimental conditions is not further required, which can lead to fast method development.     

有机酸在电感耦合等离子体质谱中基体效应的研究

研究了乙二酸、乳酸、酒石酸和柠檬酸等有机试剂对不同质量和不同电离电位元素电感耦合等离子体质谱信号的影响。结果表明,随着雾化气流速的调节,低浓度有机酸介质对所分析元素具有增强效应,尤其是对电离电位在9～11 eV的Be,Zn,As,Se,Sb和Hg等高电离电位元素的影响。酒石酸的增强效应显著大于乙二酸、乳酸、柠檬酸。探讨了有机酸的增强机理。利用酒石酸对Be,Zn,As,Se,Sb和Hg等的增强特性,测定了水标准物质SRM 1640中的Be,Zn,As,Se,Sb和SRM 1641d中Hg,其测定结果与标准样品提供的标准值基本一致。     

原子吸收光度法测定钢铁及合金中的铌量

本法叙述了一氧化二氮－乙炔火焰原子吸收光度法测定铌量，用鞣酸沉淀分离和在盐酸－氢氟酸介质中加入增感剂三氯化铝，灵敏度１２μｇ／ｍＬ／１％吸收，检出限６．１μｇ／ｍＬ。     

羊八井太阳中子望远镜和中子监测器对2005年1月20日GLE事件的探测

西藏羊八井位于东经90.53°, 北纬30.11°, 海拔4310m, 垂直地磁截止刚度14.1GV. 2005年1月20日羊八井太阳中子望远镜和中子监测器探测到与X7.1/2b太阳耀斑相关的GLE事件, 其中太阳中子望远镜能量>40MeV的能道在5min(07:00—07:05UT)和20min(07:00—07:20UT)的时间间隔内计数率增长的统计显著性分别是3.7σ和6.0σ, 同时羊八井中子监测器也探测到计数率的增长,初始时间为06:51—06:52UT. 观测表明在这次GLE事件中太阳质子可被加速到能量大于10GeV.     

X射线荧光光谱检测多层薄膜样品的增强效应研究

研究了X射线荧光光谱检测多层薄膜样品的增强效应。根据多层膜中的X荧光强度理论计算公式编写了计算机程序,并计算了Zn/Fe和Fe/Zn双层膜样品中不同薄膜厚度时Fe Kα的一次荧光强度、二次荧光强度、二次荧光与一次荧光强度比以及二次荧光在总荧光强度中比例。研究发现,在多层膜样品的X射线荧光分析中,激发条件不变的情况下,元素谱线的一次荧光相对强度、二次荧光相对强度和二次荧光在总荧光强度中所占比例都随薄膜厚度及位置的变化而变化。当Fe和Zn层厚度相同时,随厚度的变化,对于Fe/Zn样品,Fe Kα二次荧光强度占总荧光强度最高为9％,而对于Zn/Fe样品这一比例最高可达35％。     

Fluorescence enhancement of oxide fluoride glass co-doped with TbF3 and SmF3

The fluorescence property of xTbF₃-BaF₂-AlF₃-GeO₂+ySmF₃ (x=0.01-40 mol%, y=0-5 wt%) glasses were investigated. The enhancement of Sm³⁺ fluorescence was recognized in the presence of Tb³⁺. Increasing Tb³⁺ content, the emission color changed from green to orange. When the intensity of fluorescence at 540 nm originated from Tb³⁺ is compared with that at 600 nm originated from Sm³⁺, the information about the concentration quenching of Tb³⁺ and Sm³⁺ was obtained. From these results, rare earth ions were dispersed identically in the glasses. After heating to 673 K or cooling to 77 K, the emission color of 20TbF₃-20BaF₂-10AlF₃-50GeO₂/mol%+0.05 wt% SmF₃ glass was reversibly changed from orange to green. In addition, while the emission from 10TbF₃-20BaF₂-10AlF₃-60GeO₂+0.01 wt% SmF₃ glass was green, its crystallized sample, prepared by annealing at 1073 K, exhibited an orange emission due to Sm³⁺ at room temperature.     

Metal nanoparticle-enhanced room temperature phosphorescence of diiodofluorescein on the filter paper substrate

<正>Metal-enhanced room temperature phosphorescence of diiodofluorescein was first observed on filter paper surface.The phosphorescence intensity is 2.5-fold brighter from diiodofluorescein on silver nanoparticles-deposited filter paper as compared with an identical control sample without silver nanoparticles.Furthermore,enhanced absorption was also observed for the same system.Our findings suggest that both singlet and triplet states can couple to surface plasmons and enhance phosphorescence quantum yields at room temperature,as well as to increase the excitation rate of lumophores at room temperature.     

Determination of Nucleic Acids Using Rivanol as the Fluorescent Probe in the Presence of SDS

ABSTRACT

The quantitative method for nucleic acids using rivanol as the fluorescent probe in the presence of SDS was proposed. Under proper conditions, addition of nucleic acids to a mixture of rivanol and SDS resulted in enhanced fluorescence and spectral shifts of rivanol-SDS system. The calibration graph was linear in the range of 0–10.0 μg/ml for CT DNA and 0–9.0 μg/ml for yeast RNA, the limit of detection was 62 ng/ml for CT DNA and 156 ng/ml for yeast RNA. CT DNA could be determined in the presence of 20%(w/w) yeast RNA.     

Sensing and fluorescence behaviors of complex formation between new lariat crown ethers bearing fluorescence sidearm and metal ions in methanol solution

Fluorescence spectroscopic properties of the complex formation between six new C-pivot16-crown-5 ethers bearing fluorescence side arms and metal ions are studied. Six new C-pivot 16-crown-5 ethers that carry fluorescence side arms were synthesized. The research also included the examination of different fluorescent behavior of the new lariat ethers in the presence of silver and sodium ions (Ag⁺ and Na⁺) in methanol. Because of the good fit of the cavity size of these 16-crown-5 ethers with the Ag⁺ and Na⁺ ions, remarkable change in fluorescent spectra were observed. The results showed that the new lariat crown ethers exhibited enhanced selectivity towards sodium ion, but silver ion show quenching abilities towards the ligands. Cooperative participations of the C-pivot side arm oxygen with the ring oxygen molecules in complexation was also confirmed by the single crystal X-ray crystallography of the complex, (C₂₇H₃₀O₇)·NaClO₄. The freezing of crown ring conformation and the diminishment of the chance of sidearm oscillation that occurred upon complexation with sodium ion are the main causes of fluorescent enhancement. The quenching caused by the addition of silver ion was found to explainable by the photo-induced electron transfer that results in the reduction of silver ions.     

利用火焰原子吸收中的增感效应测定十二醇聚氧乙烯醚的加成数

本文利用表面活性剂在原子吸收中的增感效应测定了一系列不同平均加成数的十二醇聚氧乙烯醚对镁的增感百分数,并使之与加成数相关,得到了一个线性较好的回归方程式。利用此式可以准确地测定此系列表面活性剂的加成数。