Two-dimensional multiple entrance-slit vidicon spectrometer for simultaneous multielement analysis

A new type of wavelength dispersion system for use with a multichannel detector has been developed for simultaneous multielement analysis. The system employs a monochromator with fixed grating position, and incident angle varied by horizontal displacement of the entrance slits. The overlapping spectral windows which result can be arranged to produce a composite spectrum having minimal interference from emissions by other sample constituents. Entrance slits may also be displaced vertically to create a two-dimensional system in which spectra are stacked one above the other and scanned by use of a multi-raster scanning pattern. A number of optical and performance characteristics of the system are evaluated in both the one- and two-dimensional modes, and the system is applied to the determination of Ca, Na and K in blood serum and to the determination of the exchangeable cations Ca, Na, Li and K in clay. The advantages of this system for simultaneous multielement analysis are discussed.     

A new internal conversion electron spectrometer and its application to determine the240Pu to239Pu isotope ratio

An internal conversion electron spectrometer with high energy resolution has been constructed by using a windowless Si(Li) detector. After its characteristics were examined fundamentally, it was applied to determine the²⁴⁰Pu to²³⁹Pu isotope ratio. As a result, the energy resolution realized was demonstrated to be satisfactory.     

Thermal analysis—mass spectrometer computer system and its application to the evolved gas analysis of green river shale and lunar soil samples

A thermal analysis—mass spectrometer system controlled by a computer has been developed and successfully used in the analysis of a wide variety of geochemical samples. The TA—MS computer system provides a very powerful analytical tool for the determination of volatile species released from samples over a very wide temperature and sample-size range. Use of a small laboratory computer and magnetic-tape storage units permits large quantities of analytical information to be handled and easily retrieved. The rapid scan capabilities of the quadrupole mass spectrometer operating under computer control are especially useful for following the rapidly changing composition of the evolved gases released from samples during heating under vacuum conditions. Samples of volatile-rich Green River shale and two lunar soils have been analyzed to show the utility of the TA—MS computer system.     

A complexity-based measure and its application to phylogenetic analysis

In this article, we propose two well-defined distance metrics of biological sequences based on a universal complexity profile. To illustrate our metrics, phylogenetic trees of 18 Eutherian mammals from comparison of their mtDNA sequences and 24 coronaviruses using the whole genomes are constructed. The resulting monophyletic clusters agree well with the established taxonomic groups.     

Water-soluble conjugated polymer-induced self-assembly of gold nanoparticles and its application to SERS

Gold nanochains were prepared by the assembly of citrate-stabilized gold nanospheres induced by cationic conjugated polymers. This assembly method was rapid, and the assembled product was very stable. A longitudinal plasmon resonance band was formed as a result of the coupling of gold nanoparticles and can be tuned from visible to near-infrared by adjusting the polymer/Au molar ratio. The gold nanochains were used as a SERS substrate and gave an enhancement factor of 8.4 x 10 (9), which is approximately 400 times larger than that on the isolated gold nanosphere substrate. The giant SERS enhancement is ascribed to the large electromagnetic fields of coupled gold nanoparticles.     

Inductively-coupled plasma/atomic emission spectrometry of sulfur with a vacuum scanning spectrometer and its application to the analysis of coal liquefaction catalysts

Inductively-coupled plasma/atomic emission spectrometry with a high-resolution vacuum scanning monochromator is described for the determination of sulfur at 180.734 nm. The behavior of the signal-to-background ratio is investigated as functions of RF power, argon gas flow rate and observation height above the load coil. Under the operating conditions selected, the detection limit is 3 μg l^?1. The Se I 196.090-nm line is chosen as internal standard, because the S/Se line pair exhibited the least change with carrier gas flow rate and acid concentration of solution. Sulfur in NiMo and CoMo/ Al₂O₃ catalysts used for coal liquefaction is determined as S(II) and S(VI) species. The total amount of the species agreed well with the sulfur value obtained by the conventinal combustion method.     

Edge spreading lithography and its application to the fabrication of mesoscopic gold and silver rings

A new form of edge lithography, edge spreading lithography (ESL), has been demonstrated and applied to the formation of coinage metal rings. In this process, alkanethiols are delivered from a flat PDMS stamp to the surface of a metal film through a two-dimensional array of spherical silica colloids. The thiols further spread on the metal surface, forming highly ordered SAMs in the form of a ring pattern. Following lift-off of beads, the pattern in the SAMs can be transferred into the metal film through wet chemical etching, with SAMs serving as the resist. The dimensions of the rings can be readily controlled by several parameters such as the beads diameter, the concentration of the thiol solution, and the contact time between the stamp and the silica beads.     

Quadrupole mass spectrometer for residual gas analysis and SIMS application

Summary A combined secondary ion optics has been developed which includes both the ion source for residual gas analysis and the secondary ion optics for Secondary Ion Mass Spectrometry (SIMS). The change from one mode to the other can be done by changing only the electric connections without venting the vacuum chamber. The presented combination of the two methods allows the interpretation of SIMS spectra with higher reliability.     

Potentiometric redox determination of gold(III) and its application to alloys

The simple potentiometric method proposed for the indirect determination of 1–10 mg of gold(III) is based on reduction to the metal with excess of cobalt(II) in the presence of 1,10-phenanthroline or 2,2'-bipyridine at pH 3 and 50°C, and titration of the unused cobalt(II) complex with iron(III) chloride solution. Many metal ions can be tolerated; Ag(I) and Pd(II) are eliminated by precipitation with sodium chloride and 1,10-phenanthroline or 2,2'-bipyridine, respectively, but Hg(II), Fe(III) and Pt(IV) interfere. The method is applied to the determination of gold in alloys.     

A bi-ligand co-functionalized gold nanoparticles-based calcium ion probe and its application to the detection of calcium ions in serum

In this study, the use of bi-ligand co-functionalized gold nanoparticles in a highly selective and sensitive colorimetric probe for Ca(2+) ions is demonstrated and this probe also determined the concentrations of Ca(2+) ions in serum samples.     

Electrochemical behavior of organosoluble gold nanoclusters and its application

Journal of Solid State Electrochemistry - This contribution described the electrochemical study of organosoluble gold nanoclusters (AuNCs).The AuNCs were characterized with UV-vis absorption...     

An anticoincidence-shielded Ge(Li) gamma-ray spectrometer and its application to radioanalytical chemistry problems

An anticoincidence-shielded Ge(Li) γ-ray spectrometer incorporating a largevolume, high-resolution coaxial diode inside a large plastic phosphor shield is described. It provides a peak-to-Compton ratio of 245: 1 for¹³⁷Cs and a significantly improved sensitivity for both low- and high-level radionuclide measurements. Examples of its application to neutron activation analysis, analysis of proton activated sources, and environmental radionuclide analysis are illustrated. This paper is based on work performed under United States Atomic Energy Commission Contract AT(45-1)—1830.     

A new internal conversion spectrometer and its characteristics

A new internal conversion electron spectrometer with high energy resolution has been developed using a windowless Si(Li) detector, and its characteristics are examined and discussed. As a result, it is confirmed that the energy resolutions are 0.48 keV in FWHM for 42 keV electrons and 1.43 keV for 624 keV electrons, respectively.     

Gold-nanoparticle on the surface of L-cysteine modified gold electrode and its application

A sensor based on gold nanoparticle on the surface of L-cysteine modified gold electrode is prepared. Electrochemical behavior of dopamine hydrochloride is investigated. The linear relation between peak current of dopamine hydrochloride and scan speed in the range of 10 to 1000 mV s^?1 indicates that a diffusion-adsorption controls the process. The linearity range is 1.05 × 10^?5–7.38 × 10^?4 M with detection limit of 1.05 × 10^?6 M. The recoveries were in the range from 99.8 to 101.5% with relative standard deviations of 1.3 ～ 2.3% (n = 6). The modified electrode under ambient conditions over a period of 2 weeks has an excellent repeatability and reproducibility.     

Design and construction of glow discharge-ion trap mass spectrometer (GD-ITMS) and its application for the analysis of volatile organic samples

In this study, we present a newly designed see-through type hollow cathode glow discharge (St-HCGD) cell developed for the analysis of volatile organic materials in an ion trap mass spectrometer. The cell was interfaced with a homemade ion trap mass spectrometer by adopting skimmer and sampler in an optimized dimensions based on the computer simulation done by SIMION software. The St-HCGD cell has a relatively small size (4×4×7 cm) with the diameter of the inner tube of 0.25′′. The anode and cathode were made of stainless steel-304 and helium was used as a buffer gas for discharge to enhance the Penning ionization process rather than sputtering process. Mass spectra of volatile organic samples such as benzene, toluene, cyclohexane were obtained by using the St-HCGD-ITMS.     

A study on proton induced X-ray analysis and its application to environmental samples

Proton induced X-ray analysis has been studied by the 5 MV Van de Graaff of Tohoku University emphasizing on backing materials and angular dependence of background. The method has further been applied to analyses of some environmental samples. From experimental results, it was found that 4 μm Mylar foil among Formvar, Mylar and carbon gives sufficiently low background spectrum, high sensitivity and good mechanical strength. The detection limit is much improved at the backward direction with respect to the incident beam comparing with that at 90° which has usually been adopted. The analytical results on soil and aerosol samples were compared with those by the Atomic Absorption Spectrophotometrical method (AAS). Vanadium can easily be analysed by this method, but not by the AAS method. Milk and human milk were also analysed.     

A streamlined approach to the analysis of volatile fatty acids and its application to the measurement of whole-body flux

Volatile fatty acids (VFAs) are produced in the human colon by the bacterial breakdown of carbohydrates that escape digestion and absorption in the small intestine. They have important local and systemic effects on gastrointestinal and nutritional functions. Measuring their production is difficult because of inaccessibility of sampling sites and low circulating concentrations. Stable isotope tracer techniques are a way to measure VFA production but require measurement of isotope dilution in blood and other biological fluids. We have developed a streamlined and robust method to measure the concentration and enrichment of [(2)H]-labelled VFAs by gas chromatography/mass spectrometry (GC/MS) and [(13)C]-labelled VFAs by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). Both types of analysis were carried out on the same samples allowing multiple tracer studies to be conducted. Good accuracy and repeatability were found for GC/MS analysis of [(2)H]-labelled VFAs. Careful handling of the background contribution, especially acetate, allowed quantitation of concentration and enrichment within the analysis. GC/C/IRMS analysis of [(13)C] VFAs was also achieved with good accuracy and repeatability. This methodology was used to determine whole-body acetate production in two subjects using multiple tracers ([(2)H(3)]- and [1-(13)C]acetate) and blood and urine sampling. Whole-body acetate flux was similar when measured either with [(2)H(3)]- or [1-(13)C]acetate, and when flux was determined from plasma or urine tracer enrichment. This new method will permit rapid and accurate measurement of VFA flux using [(2)H]- and/or [(13)C]-labelled VFAs as tracers. Measurements of the contribution of colonic VFA production to whole-body VFA flux are now possible.     

A sum-over-state scheme of analysis of hyperpolarizabilities and its application to spiroconjugated molecular system

The static first and second hyperpolarizabilities of a number of spiromolecules with varying degree of polarity have been calculated at the HF and MP2 level using the 6-31+G* basis set and the B3LYP/6-31+G* optimized geometry. The variation of mean second hyperpolarizability in these molecular systems has been explained in terms of the ground state dipole moment, mean linear polarizability and second-order polarizability. A number of relationships among these quantities have been derived in the framework of the sum-over-state scheme and the generalized Thomas–Kuhn sum rule. The spiroconjugation results in the significant increase of the mean polarizability. The appreciable enhancement of first hyperpolarizability due to the spiroconjugation between two dipolar monomer units has been accounted for the rather significant increase of the mean polarizability tensor and the ground state dipole moment. The relatively larger value of the average second hyperpolarizability of the spiroconjugated molecules compared to that of the corresponding monomers arises from the rather significant increase of the nonaxial component γ _xxyy . The replacement of spirocarbon by spirosilicon results in the enhancement of the cubic polarizability manifold. The donor–acceptor substituted spirocompounds are predicted to be the superior third-order nonlinear optical (NLO) phores. The nature of π-conjugation in the monomer units around the spirocenter shows a strong modulation of the NLO properties of spirocompounds. The influence of electron correlation on the NLO properties at the MP2 level has been found to be rather significant.     

毛细管电泳-质谱联用技术及其在蛋白质组学中的应用

蛋白质组学研究在生物学、精准医学等方面发挥着重要的作用。然而研究面临的巨大挑战来自生物样品的复杂性,因此在质谱（MS）鉴定技术不断革新的同时,发展分离技术以降低样品复杂度尤为重要。毛细管电泳（CE）技术具有上样体积小、分离效率高、分离速度快等优势,其与质谱的联用在蛋白质组学研究中越来越受到关注。低流速鞘流液和无鞘流液接口的发展及商品化推动了CE-MS技术的发展。目前毛细管区带电泳（CZE）、毛细管等电聚焦（CIEF）、毛细管电色谱（CEC）等分离模式已与质谱联用,其中CZE-MS应用最广泛。目前被广泛采用的蛋白质组学研究策略主要是基于酶解肽段分离鉴定的"自下而上（bottom-up）"策略。首先,CE-MS技术对酶解肽段的检测灵敏度高达1 zmol,已成功应用于单细胞蛋白质组学;其次,毛细管电泳技术与反相液相色谱互补,为疏水性质相近的肽段（尤其是翻译后修饰肽段）的分离鉴定提供了新的途径。基于整体蛋白质分离鉴定的自上而下"top-down"策略可以直接获得更精准、更完整的蛋白质信息。CE技术在蛋白质大分子的分离方面具有分离效率高、回收率高的优势,其与质谱的联用提高了整体蛋白质的鉴定灵敏度和覆盖度。非变性质谱（native MS）是一种在近生理条件下从完整蛋白质复合物水平上进行分析的质谱技术。CE与非变性质谱联用已被尝试用于蛋白质复合体的分离鉴定。该文引用了与CE-MS和蛋白质组学应用相关的93篇文献,综述了以上介绍的CE-MS的研究进展以及在蛋白质组学分析中的应用优势,并总结和展望了其应用前景。