STRUCTURE EFFECTS OF SILICON AND CARBON BY CLUSTER MASS SPECTRA

Microclusters from different structures of silicon and carbon are studied by SIMS under UHV conditions in the mass range below M=200. The sputtered mass spectra of ions Sin+, Cn+ and Cn were obtained from the 10 keV O2+ primary beam bombardment. Comparisons of each spectrum in each group have shown the strong structure effects on the cluster patterns. A brief discussion on the results has been given.

Quantum Chemistry Study on Structures of Cluster Ions Nb_(n)S_(m)^(±)Generated by Laser Mass Spectra

ccording to the chemical bond theory we designed geometric structures ofcluster ions Nb_nS generated by laser ablation and calculated their electronic struc-tures using DV-X_a method of quantum chemistry. The results show that with theincrease of the cluster size the structures of the cluster ions change from a single-chain to a double-chain, then to a planar-net, and linking up to a net at Nb_3. Thenegative cluster ions tend to form a divergent configuration due to the extra chargeson it.

An Explanation on the Electron Ionization Mass Spectra of Crown Ethers by MNDO Computational Method

he bond lengths and bond orders of four kinds of chemical bonds in crownethers(15) were calculated based on the model molecules using MNDO method.With the calculation results, some predictions to the EI mass spectral fragmenta-tion behaviour of crown ethers are suggested. The EI mass spectra of studied crownethers are in satisfactory agreenient with the predictions.

Study of scattering from time-varying Gerstners sea surface using second-order small slope approximation

Backscattered fields from one-dimensional time-varying Gerstners sea surface are calculated utilising the secondorder small slope approximation. It is well known that spectral properties of the backscattered echoes relate to the velocity of the small elementary scatterers on sea surface profiles. Therefore, modeling Doppler spectra from the ocean requires an accurate description of the sea surface motion. The profile of nonlinear Gerstners sea surface shows verticalskewness of sea waves, it is sharper at the crest and flatter at the trough than linear waves, and its maximum slope position is closer to the crest than to the trough. Furthermore, the horizontal component of the small elementary scatterers orbit velocity on the sea surface, which yields noticeable influence on Doppler spectra, can be obtained conveniently by Gerstners sea surface model. In this study the characteristics of Doppler spectra of backscattered fields from time-varying Gerstners sea surface are investigated and the dependences of the Doppler frequency and the Doppler bandwidth on the parameters, such as the wind speed, the radar frequency, the incident angle, etc. are discussed. It is shown that the Doppler bandwidth of microwave scattered fields from Gerstners sea surface is considerably broadened. For the case of high frequency backscattered fields, the values of the higher-order spectrum peaks are larger than those obtained by linear sea surface.

A STUDY OF DOUBLY CHARGED ION MASS SPECTRA(2E SPECTRA) OF BIPHENYL DERIVATIVES

The 2E spectra and substituent effects and target gas pressure dependence of the 2E spectra of 7 biphenyl derivatives were discussed. The electron-donating groups favour the molecular ions, but the electron withdrawing groups favour the fragaent ions produced by losing the substituents from molecular ions. The variation of target gas pressure affects the TIC,sample ion current,and the ratio of sample ion current to TIC sharply.However it has no effect on the fragmentation pattern.

MASS SPECTRA OF SUBSTITUTED BENZYLGLYOXALS WITH DEUTERIUM EXCHANGE

Mass spectral behavior of some deuterated and non-deuterated substituted benzylglyoxals was characteristic in enolic structure which was also proved by NMR spectrum. Fragmentation of the title compounds in their mass spectra was ressonably explained in this paper.

THE NEGATIVE-ION CHEMICAL-IONIZATION MASS SPECTRA OF SOME 2, 6, 7-TRIOXA-1-PHOSPHABICYCLO[2.2.2]OCTANE-1-OXIDE DERIVATIVES

The metaphosphate anion, PO_3, was detected in the negative-ion chemicalionization mass spectra of 2,6,7-trioxa-1-phospbabicyclo[2.2. 2] octane-1-oxides.

抗肿瘤药物卡铂的分离和杂质鉴定

本文选择卡铂注射液为样本,对其进行液相色谱质谱分析,旨在解析铂类化合物的色谱行为和质谱特性。在分析过程中,采用了含0.1%甲酸的水-乙腈为流动相,确保在高效液相色谱(HPLC)系统中实现梯度洗脱,进一步在飞行时间质谱(TOF/MS)中以正离子模式对样品进行电离处理。研究结果显示,卡铂分子及其相关物质在XDB-C18色谱柱上实现了良好的分离,减少了铂类化合物的定性分析过程中的干扰,且TOF/MS谱图上呈现出卡铂分子的同位素特征峰。此外,还对卡铂分子的质谱裂解途径进行了归纳总结,为理解其质谱行为提供了有价值的见解。综上所述,本研究所采用的分析方法不仅简便快捷,而且精准可靠,为铂类化合物的定性定量分析提供了一定的参考。

新型苯环己哌啶衍生物溴胺酮的表征与分析

为了对案件缴获的疑似毒品进行分析,确认化合物种类,建立化合物的表征数据,本文基于气相色谱–质谱联用技术(GC-MS)、液相色谱–高分辨飞行时间质谱联用技术(LC-QTOF)、傅里叶变换红外光谱技术(FT-IR)、核磁共振氢谱(1HNMR)及碳谱(13CNMR)、X射线单晶衍射(X-raydiffractionofsingle crystal)等多种手段对目标化合物进行分析和表征。测定了已列管的氯胺酮和氟胺酮的二级质谱,建立中性丢失质谱碎片信息,并与目标化合物进行比对。通过多种分析手段与中性丢失质谱碎片信息比对结果,确认该化合物为溴胺酮。新型苯环己哌啶衍生物溴胺酮存在一定的毒品替代和滥用风险,本研究建立的溴胺酮的分析与表征数据能够为公安机关对溴胺酮的鉴定工作提供参考依据。

电感耦合等离子体质谱法结合化学计量学分析车前草药材中12种元素

目的建立同时测定车前草药材中12种元素的电感耦合等离子体质谱(ICP-MS)法,并进行化学计量学分析。方法射频功率为1800 W,等离子体气流量为15 L/min,载气流量为1 L/min,采样深度为12 mm,辅助器流量为1 L/min,雾化室温度为2.0℃,测量模式为动能歧视(KED)模式,碰撞气体积流量为6.0 mL/min,进样冲洗时间为35 s,蠕动泵泵速为50 r/min,扫描3次。根据3个产地15批车前草药材样品中12种元素的含量测定结果,建立特征图谱,并进行主成分分析。结果镉(Cd)、铅(Pb)、铜(Cu)、钠(Na)、锌(Zn)、钾(K)、铝(Al)、汞(Hg)、钙(Ca)、镁(Mg)、砷(As)、铁(Fe)质量浓度分别在0~100 ng/mL、0~100 ng/mL、0~500 ng/mL、0~500 ng/mL、0~1000 ng/mL、0~500 ng/mL、0~500 ng/mL、0~20 ng/mL、0~500 ng/mL、0~1000 ng/mL、0~100 ng/mL、0~1000 ng/mL范围内与仪器响应值线性关系良好(r≥0.9992,n=6);精密度、重复性、稳定性试验结果的RSD均小于5%;平均加样回收率为82.72%~91.10%,RSD为1.55%~4.69%(n=6)。15批车前草12种无机元素的平均含量分别为0.36,1.58,9.16,10.51,54.71,9.35,34.86,0.16,16.81,112.64,1.08,100.04 mg/kg。3个产地车前草药材中12种元素特征图谱的峰形基本相似。Mg、Fe、Zn、Al是车前草药材的特征元素;15批车前草药材样品的质量存在一定差异,其中贵州毕节所产的质量较好。结论建立的ICP-MS法操作简单、结果准确,可用于车前草药材中12种元素的含量测定;特征图谱及主成分分析可为车前草药材的开发利用和质量控制提供参考。

Analysis of GC×GC fingerprints from medicinal materials using a novel contour detection algorithm:A case of Curcuma wenyujin

This study introduces an innovative contour detection algorithm,PeakCET,designed for rapid and efficient analysis of natural product image fingerprints using comprehensive two-dimensional gas chromatogram(GC×GC).This method innovatively combines contour edge tracking with affinity propagation(AP)clustering for peak detection in GC×GC fingerprints,the first in this field.Contour edge tracking signif-icantly reduces false positives caused by“burr”signals,while AP clustering enhances detection accuracy in the face of false negatives.The efficacy of this approach is demonstrated using three medicinal products derived from Curcuma wenyujin.PeakCET not only performs contour detection but also employs inter-group peak matching and peak-volume percentage calculations to assess the compositional similarities and differences among various samples.Furthermore,this algorithm compares the GC×GC fingerprints of Radix/Rhizoma Curcumae Wenyujin with those of products from different botanical origins.The findings reveal that genetic and geographical factors influence the accumulation of secondary metabolites in various plant tissues.Each sample exhibits unique characteristic components alongside common ones,and vari-ations in content may influence their therapeutic effectiveness.This research establishes a foundational data-set for the quality assessment of Curcuma products and paves the way for the application of computer vision techniques in two-dimensional(2D)fingerprint analysis of GC×GC data.

液相色谱-质谱联用技术在中药研究中的应用

液相色谱-质谱联用技术将液相色谱的高分离能力与质谱强大的定性功能相结合,可以实现对复杂样品高灵敏度、高选择性的快速分离和准确定性定量分析,广泛应用于药物分析研究特别是中药分析研究中。阐述了液相色谱-质谱联用技术在中药成分研究,指纹图谱研究和中药代谢动力学研究中的应用,旨在对中药研究提供一定的技术支持。

基于联产工艺的橙皮精油气相色谱-质谱指纹图谱的构建及成分分析

目的构建果胶精油联产工艺获得的橙皮精油的指纹图谱,并进行成分分析。方法通过气相色谱-质谱法采集20批次橙皮精油样品的总离子流图(total ions current,TIC),运用“中药色谱指纹图谱相似度评价系统(2012版)”寻找共有峰并建立对照指纹图谱,采用美国国家标准与技术研究院(National Institute of Standards and Technology,NIST)谱库检索结合保留指数技术对共有峰进行成分鉴定,运用SPSS 29.0软件对共有峰进行主成分分析。结果指纹图谱的精密度、重复性和稳定性等方法学考察符合要求,所有样品TIC图相似度均大于0.998,提炼出9个共有峰,经过质谱鉴定,在共有峰中,D-柠檬烯相对含量最高,占82.77%,其次为月桂烯、烩烯、右旋α-蒎烯等,依次占比8.79%、3.62%、3.27%;经主成分分析,前两个主成分因子的累积方差贡献率为67.4%,微量成分烩烯和3-蒈烯对主成分因子的贡献最大。结论对由果胶精油联产工艺获得的橙皮精油建立了气相色谱-质谱指纹图谱,探明其共性化合物成分及影响力,为其质量控制提供了科学依据。

HL-2A装置硅化镀膜壁处理控制杂质行为研究

硅化壁处理能有效控制等离子体杂质和再循环水平,是HL-2A装置的常规壁处理手段。介绍了HL-2A装置的硅化壁处理系统以及硅化镀膜壁处理控制杂质行为的主要研究进展。HL-2A装置硅化壁处理系统包括离线硅化和在线硅化壁处理系统,分别采用辉光放电辅助沉积以及等离子体放电辅助沉积进行硅化镀膜壁处理。实验结果表明,离线硅化壁处理后氧杂质明显降低,但随着实验进行会逐渐增加,硅化镀膜寿命约150炮。为进一步开展研究,HL-2A采用了在线硅化壁处理技术,研究发现在线硅化壁处理过程中碳、氧、铁等杂质均有所减少。两种硅化方式下真空室内的H_(2)O、CO含量均明显降低,在线硅化壁处理耗气量远少于离线硅化。通过硅化壁处理,有效地提升了HL-2A等离子体性能,也为未来聚变装置稳态运行器壁的处理提供了重要技术参考。

Study of Non-Thermal DC Arc Plasma of CH_4/Ar at Atmospheric Pressure Using Optical Emission Spectroscopy and Mass Spectrometry

Non-thermal C/H/Ar plasmas are widely applied to carbonaceous material production and processing.In this work,plasma parameters and gaseous species of the atmospheric non-thermal C/H/Ar plasmas produced by an atmospheric-pressure DC arc discharge generator in CH_4/Ar were investigated.The voltage-current characteristics were measured for different CH_4/Ar ratios.Optical emission spectroscopy was employed to analyze the electron excitation temperature,gas temperature and electron density under various discharge conditions.The hydrocarbon molecules produced in the CH4/Ar plasmas were detected with photoionization mass spectrometry.The optical spectral results demonstrated that the electron excitation temperature was 0.4-1 eV,the gas temperature was 2800-4200 K and the electron density was in the range of（5-20）×10^15 cm^-3.The mass spectrum indicated that a variety of unsaturated hydrocarbons（C2H4,C3H6,C6H6,etc.） and several highly unsaturated hydrocarbons（C4H2,C5H6,etc.） were produced in the non-thermal arc plasmas.

Mass Spectrometric Study of Acetylated Glycopyranosyl Azides

Introduction Glycosyl azides are useful, versatile intermediates for the synthesis of N-glyeosyl derivatives and other biologically important non-carbohydrate derivatives since the azido group can be introduced readily into aliphatic, aromatic and heterocyclic systems, and can be transformed into other functional groups and utilized for the synthesis of hetero-

FAB MASS SPECTROMETRY OF THE PHENOLATEBRIDGED N_8O_3 SCHIFFBASE CRYPTANDS

The fast atom bobardment mass spectra of phenolate-bridged N8O3 Schiff-2base cryptands derived from tris （2-aminoethyl） amine （tren） with 2, 6-dlformyl-4-R-phenol （Cryptand H3L1, R=OMe） H3L3, Br, and H3L4, Ph) in the presence of NaOH or KON in methanol at ambient temperature was investigaed and compared with IR, UV-Vis, 1H and 13H NMR. The characteristic spectra of the cryptates posseessing different proton form cryptands were discussed.

REPRESENTATION OF STATISTICAL PROPERTIES OF WAVE GROUPS FOR SEA PROCESSES WITH DOUBLE-PEAKED SPECTRA

A method using group-induced second-order long waves(GSLW) to represent statistical properties of wave groups with double-peaked spectra is put forward in this paper on the basis of the GSLW theory. The GSLW is regarded as a weighted linear superimposition of the second-order long Wave induced by the low peak frequency section and that induced by the high peak frequency section. There is a parabolic relationship between the GSLW and the wave envelope. Then the probability density function and the distribution function of the GSLW amplitude are derived. Thus the formulas for the average time duration and the mean length of runs can be derived. Good agreement between theoretical results and measured values was achieved. as verified with the measured double-peaked spectra in different regions.

Mass Spectrometric Characterization of a Thermolabile Metabolite of Camazepam

Incubation of camazepam [3-(N,N-dimethyl) carbamoyloxy-7-chloro-1- methyl-1,3-dihydro-5-phenyl-2H-1,4-benzodiazepin-2-one] with rat liver microsomes and cofactors produced a 3-(N-methyl-N-hydroxymethyl) carbamoyloxy derivative as the most abundant metabolite.This metabolite was thermally unstable and was isolated from a metabolite mixture by normal-phase High-Performance Liquid Chromatography.Its struc- ture was established by chemical ionization and ^(252)Cf plasma desorption time-of-flight mass spectral analyses.

Plasma Immersion Ion Implantation of the Pea Seed and Its RBS Spectra

Plasma immersion ion implantation (PI^3), a new technique with certain advantages over biological samples, was developed. Argonion as well as nitrogen ion implantation of the pea seeds has been carried out with the PI^3 implanter and their RBS spectra were also studied. The results show that the mass deposition effect of ion implantation on biological samples can be achieved with the PI^3 implanter. In addition, there is an optimal implantation time for a given treatment condition. It presents new possibilities for the ion implantation into biological samples.