气相法分析3-氯-2-羟丙基三甲基氯化铵中的微量有机杂质

 以氯仿为萃取剂 ,对 3 氯 2 羟丙基三甲基氯化铵 (CHPTMA)水溶液进行萃取 ,用气相法分析了CHPT MA溶液中的微量有机杂质环氧氯丙烷和 1 3 二氯丙醇。柱为 2m× 3mmi d 的不锈钢填充柱 ,固定相为10 %的PEG 2 0M ,载体为ChromosorbW/AW。环氧氯丙烷和 1,3 二氯丙醇的回收率分别为 97 5 %～ 10 5 0 %和93 3%～ 98 8% ,相对标准偏差分别为 11 5 %和 13 1% ,最低检测限分别为 5 0 μg/g和 10 0 μg/ g。     

铜中杂质成分标准物质的研制

介绍铜中9种杂质成分标准物质的研制方法。以1号纯铜为基体，配入硫、铁、铅、锌、镍、铋、锑、磷、砷及锡共10种杂质成分，采用雾化喷粉加工工艺，保证了样品的均匀性。对样品表面作了抗氧化保护处理。采取多家实验室协作定值的方式对除砷外的9种杂质成分进行定值。5年的跟踪检验结果表明，该标准物质稳定性良好。     

Influence of vanadium doping on the behavior of YBa_2Cu_3O_7-y

YBa2Cu3-xVxO7-y(x=0, 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6) superconductors have been prepared. X-ray diffraction shows that the system remains orthorhombic for all compositions studied, but for x > 0.4 V2O5 was detected as an impurity phase. Substitution of V5+ for Cu2+ occurs in the Cu(2) sites on the Cu(2)-O planes. The introduction of the high valence element, vanadium, produces the extra free-electrons. These electrons recombine with the positive carrier of the system. It makes depression of the mobility and the Hall number of YBa2Cu3-xVxO7-v and also results in a depression of TC.     

Direct determination of rare earth impurities in high purity erbium oxide dissolved in nitric acid by inductively coupled plasma mass spectrometry

A novel method was developed for the direct determination of trace quantities of rare earth elements (REEs) in high purity erbium oxide dissolved in nitric acid by inductively coupled plasma mass spectrometry (ICP-MS) in this work. The mass spectra overlap interferences arose from Er matrix on the neighbouring and monoisotopic analytes of ¹⁶⁵Ho(100) and ¹⁶⁹Tm(100) were eliminated by adjusting instrumental peak resolution value from 0.7 to 0.3 amu. The matrix suppression effect of Er on the ion peak signals of REEs impurities was effectively compensated with spiking In as internal standard element. The limit of quantitation (LOQ) of REEs impurities was from 0.0090 to 0.025 μg g⁻¹, the recoveries of spiked sample for REEs were found to be in the range of 90.3-107% through using the proposed method and relative standard deviation (R.S.D.) varied between 2.5% and 6.7%. The novel methodology had been found to be suitable for the direct determination of trace REEs impurities in 99.999-99.9999% high purity Er₂O₃ and the results obtained from this method keep in good agreement with that acquired from high resolution ICP-MS.     

新型除草剂及其杂质的LC-MS和GC-MS分析

High performance liquid chromatography (HPLC) and electrospray ionization mass spectrometry (ESI-MS) have been utilized to analyze the synthesized 2-(2-arylaminomethylphenoxy)pyrimidine derivatives, which are a new kind of environmentally benign herbicides and have passed the temporary pesticide registration. The identification of main product and impurities has been achieved according to the UV and mass spectra. Moreover, one impurity, introduced by the raw material in the last step of the synthetic route, was identified by GC-MS analysis. It can be concluded that the combination of chromatography and mass spectrometry, including LC-MS and GC-MS, provided a vital tool of the pesticide science.     

Simple test system for single molecule recognition force microscopy

We have established an easy-to-use test system for detecting receptor-ligand interactions on the single molecule level using atomic force microscopy (AFM). For this, avidin-biotin, probably the best characterized receptor-ligand pair, was chosen. AFM sensors were prepared containing tethered biotin molecules at sufficiently low surface concentrations appropriate for single molecule studies. A biotin tether, consisting of a 6 nm poly(ethylene glycol) (PEG) chain and a functional succinimide group at the other end, was newly synthesized and covalently coupled to amine-functionalized AFM tips. In particular, PEG₈₀₀ diamine was glutarylated, the mono-adduct NH₂-PEG-COOH was isolated by ion exchange chromatography and reacted with biotin succinimidylester to give biotin-PEG-COOH which was then activated as N-hydroxysuccinimide (NHS) ester to give the biotin-PEG-NHS conjugate which was coupled to the aminofunctionalized AFM tip. The motional freedom provided by PEG allows for free rotation of the biotin molecule on the AFM sensor and for specific binding to avidin which had been adsorbed to mica surfaces via electrostatic interactions. Specific avidin-biotin recognition events were discriminated from nonspecific tip-mica adhesion by their typical unbinding force (∼40 pN at 1.4 nN/s loading rate), unbinding length (<13 nm), the characteristic nonlinear force-distance relation of the PEG linker, and by specific block with excess of free d-biotin. The convenience of the test system allowed to evaluate, and compare, different methods and conditions of tip aminofunctionalization with respect to specific binding and nonspecific adhesion. It is concluded that this system is well suited as calibration or start-up kit for single molecule recognition force microscopy.     

Numerical and analytic study of rough surface morphology on the angular distribution of eroded impurity

The impact of rough surface morphology on the angular distribution of eroded impurities has been investigated with the three‐dimensional (3D ) rough surface code SURO and a newly developed analytic model. The property of the rough surface structure can be described by the shadow angle of the rough surface in SURO , which is defined as the ratio of the horizontal characteristic length to the initial surface roughness. The SURO simulation results show that the influence of the rough surface on the angular distribution of eroded impurities comes into play when the shadow angle is larger than a threshold value. The larger shadow angle of the rough surface leads to a stronger shift of the angular distribution of the eroded impurities. Different rough surface topographies have been used in the SURO code to check the angular distribution of the eroded impurities. It is found that the shift tendency of the angular distribution is similar for different structures of the rough surface. Based on the numerical modelling results, an analytical model has been developed to investigate the impact of the shadow angle on the angular distribution of the eroded impurities, which shows the consistent result as the SURO simulations.     

Thermoluminescence of Chromium Doped Cd2Nb2O7 Crystals

The exposure of the Cd₂Nb₂O₇:Cr crystal to monochromatic light with wavelength shorter than 600 nm at 12 K decreases the Cr^3? photoluminescence emission and allows us to observe thermoluminescence within 60–200 K during subsequent heating of the crystal at a rate of 0.077 K/s. The glow curve of thermoluminescence revealed a rather complex structure with two pronounced intensive glow peaks at 91 and 180 K and four rather weak peaks at 99, 117, 132, and 155K. An analysis of the glow peaks by “an initial rise” gave evidence of many various charge carrier traps with activation energies from 150 to 470 meV. Since a comparison of the thermoluminescence and photoluminescence emission spectra showed that these spectra are identical, it was concluded that the thermoluminescence glow peaks are associated with thermal release of charge carriers from shallow traps followed by Cr^4?→Cr^3?(²E) and/or Cr^2?→Cr^3?(²E) charge capture and ²E→⁴A₂ radiative decay of Cr^3?(²E) ions.     

Baclofen impurities: Facile synthesis and novel environmentally benign chromatographic method for their simultaneous determination in baclofen

An efficient, economic and high yielding method was described for the synthesis of baclofen (BAC) pharmacopoeial impurities (impurity A and impurity B) which can be used for gram‐scale synthesis. Furthermore, a novel ecofriendly thin‐layer chromatographic TLC–densitometric method was established and validated for the determination of BAC and its synthesized impurities. The developed TLC–densitometric method is based on the chromatographic separation using TLC plates (60 F₂₅₄) using a green mobile phase of ethyl acetate–methanol–ammonia solution, 33% (8:2:0.1, by volume) with UV scanning at 220 nm. The proposed method was validated with respect to International Conference on Harmonization guidelines. The validated method was successfully applied for determination of BAC in pure form and in its commercial dosage form. Additionally, the greenness profile of the developed method was evaluated and compared with those of the reported chromatographic methods. The developed method was found to be superior to the published methods, being environmentally benign.     

Flux and fluence dependence of disorder produced during implantation of 11B in silicon

The flux and fluence dependence of disorder produced in silicon during the implantation of ¹¹B has been investigated at room temperature, -50°C. and -120°C. Implantations were carried out with 200 keV ¹¹B ions using current densities in the range from 0.06μA/cm² to 15μA/cm², and the disorder monitored by measuring the energy spectra of backscattered protons which were incident on the sample at 450 keV parallel to a (110) axis. Significant differences in the dependence of the disorder on ¹¹B flux and fluence were observed between the implantations performed at room temperature and those carried out at the two lower temperatures.