Determination of Carbon and Nitrogen Isotope Fractions in Tartaric Acid, Oxalic Acid, Glucose and Fructose—National Center of High Technologies of Georgia

Tartaric acid, oxalic acid, glucose, and fructose are highly important compounds. A comprehensive study of these substances is fascinating from a scientific perspective. They are key components found in wine, vegetables, and fruits. Understanding the isotopic compositions in organic compounds is crucial for comprehending various biochemical processes and the nature of substances present in different natural products. Tartaric acid, oxalic acid, glucose, and fructose are widely distributed compounds, including in vegetables and fruits. Tartaric acid plays a significant role in determining the quality and taste properties of wine, while oxalic acid is also prevalent but holds great interest for further research, especially in terms of carbon isotopic composition. We can unveil the mechanisms of processes that were previously impossible to study. Glucose and fructose are the most common monosaccharides in the hexose group, and both are found in fruits, with sweeter fruits containing higher amounts of these substances. In addition to fruits, wheat, barley, rye, onions, garlic, lentils, peppers, dried fruits, beans, broccoli, cabbage, tomatoes, and other foods are also rich sources of fructose and glucose. To determine the mass fraction of the carbon-13 isotope in these compounds, it is important to study their changes during natural synthesis. These compounds can be modified with a carbon center. According to the existing isotopic analysis method, these compounds are converted into carbon oxide or dioxide [1]. At this point, the average carbon content in the given compound is determined, but information about isotope-modified centers is lost. Dilution may occur through the transfer of other carbon-containing organic compounds in the sample or by dilution with natural carbon or carbon dioxide during the transfer process. This article discusses the possibility of carbon-13 isotope propagation directly in these compounds, both completely modified and modified with individual carbon centers. The literature provides information on determining carbon-13 substance in organic compounds, both with a general approach and for individual compounds [2] [3].

Methods for the Determination of Stable Isotopes of Carbon and Nitrogen Directly in Valine, Proline, Glutamine, and Glutamic Acid

Amino acids are very important compounds for the body and are involved in important functions that keep us healthy. Amino acids are essential components such as valine, proline, glutamine and glutamic acid. They can be synthesized either naturally or artificially. To examine the metabolism and regulate the synthesis process, compounds labeled with nitrogen or carbon isotopes need to be used. These isotopic compounds allow for more extensive research and enable studies that would otherwise be impossible. However, their use is dependent on the availability of simple, efficient methods for isotopic analysis. Currently, the determination of the atomic fraction of carbon and nitrogen isotopes is only possible through their conversion into molecular nitrogen or carbon monoxide or carbon dioxide. This leads to the loss of information about isotopic enrichment in specific centers of the molecule. This article explores a new direct approach to determining the atomic fraction of carbon and nitrogen isotopes in the isotope-modified or identical centers of these compounds. This method eliminates the transfer process and dilution due to nitrogen and carbon impurities. It is now possible to simultaneously determine the atomic fraction of nitrogen and carbon isotopes in the research substance. This method can be applied to amino acids, making it an effective tool for proposing new research methods. Several articles [1] [2] [3] have proposed similar methods for organic compounds and amino acids.

Gate/Geant4-based Monte Carlo simulation for calculation of dose distribution of 400 MeV/u carbon ion beam and fragments in water

The applications of carbon ion beam in tumor therapy have attracted more attention in recent years.Monte Carlo simulation is an important approach to obtain accurate radiotherapy parameters. In this work, a400 Me V/u carbon ion beam incident on water phantom was simulated with Gate/Geant4 tools. In methods, the authors set up a carbon ion beam source according to the experiment parameters of Haettner, defined the geometries and materials, set up the physics processes, and designed the means of information collection. In results,the authors obtained the longitudinal dose distribution, the lateral dose distribution, and the relative uncertainty of dose. The dose contributions of all kinds of fragments were calculated detailedly and compared with the Francis results. This work is helpful for people's understanding of the dose distributions produced by carbon ion beam and fragments in water. The simulation method is also significative for radiotherapy treatment planning of carbon ion beam, and it is easy to extend. For obtaining a special result, we may change the particle energy, particle type,target material, target geometry, physics process, detector,etc.

Fragmentation in ^16 O-emulsion interactions at 3.7 A GeV

The topology of ^16 O fragmentation at 3.7 A GeV in reactions with emulsion nuclei is presented. The multiplicity distributions of projectile fragments, charged secondaries and their dependences on the projectile residues are discussed.

Projectile fragment emission in the fragmentation of 56Fe on Al,C,and CH2 targets

The emission angle distribution of projectile fragments(PFs)and the temperature of PF emission sources for fragmentation of 56Fe on polyethylene,carbon,and aluminum targets at the highest energy of 497 A MeV are investigated on the basis of corrected data,using a CR-39 plastic nuclear track detector.It is found that the average emission angle of PFs increases with the decrease in PF charge for the same target,and no obvious dependence of angular distribution on the mass of the target nucleus is found for the same PF.The cumulative squared transverse momentum distribution of PFs can be well represented by a single Rayleigh distribution.The temperature of PF emission sources is extracted from the distribution,and it is about 1.0-8.0 MeV and does not depend on the mass of the target for PFs with charges of 9≤Z≤25.

Investigation of Evaporated Fragments in Intermediate Energy Heavy Ion Collisions

The reactions induced by intermediate energy heavy ions are investigated.The evap-orated fragment multiplicity and excitation energy distributions are calculated and comparedwith the experimental data of the reaction Ar+Ag at 50 and 70 MeV/u.

Mass dependence of critical parameter and multiplicity of intermediate mass fragments in heavy ion reaction

The mass dependence of critical parameters for the liquid-gas phase transition and multiplicity of intermediate mass fragment in the heavy ion reaction is qualitatively explored under the framework of lattice gas model.Some results are compared with experimental data.

Universal Behavior of Nuclear Fragmentation

We use the bond percolation model to study the multifragrnentation of197Au projectiles interact-ing with Cu target at a bombarding energy of 600 MeV/u.The charge observables and some of their dif-ferential distributions are analyzed.The theoretical results agree well with the experimental data ofALADIN collaboration.This indicates that the percolation model can describe reasonably the universal be-havior of nuclear fragmentation in nucleus-nucleus collisions.

Specific Mass Spectrometric Fragmentations from the Dissociation of Intermediate Ion-Neutral Complexes

It is reported that two kinds of specific mass spectrometric fragmentations are generated from dissociations of the intermediates of both the ion-neutral complex and the proton-bound complex. Collision-induced dissociation, isotopic labelling, and semi-empirical AM1 calculations were used to investigate the formation mechanism of the ion of m/z 139 from ionized tetrahydroimidazole-substituted methylene beta-diketones and the unimolecular fragmentations pathway of 3-phenyl-1-butyn-3-ol upon electron impact.

咖啡酸负离子模式质谱奇电子离子碎片的解析

通过高分辨质谱的测定与密度泛函理论方法的计算,揭示咖啡酸电喷雾负离子模式质谱的奇电子离子产生过程与机理。咖啡酸去质子分子裂解产生3个奇电子离子,分别为咖啡酸质谱裂解的第三代产物离子m/z 134(C_(8)H_(6)O_(2))、第四代产物离子m/z 108(C_(6)H_(4)O_(2))和m/z 106(C_(7)H_(6)O)。m/z 134离子来自于其前体离子m/z 135(3,4-二羟基苯乙烯离子)羟基O—H键的直接均裂,因其裂解过程较m/z 135的其他裂解相对简单并且所需能量相对较少,使质谱中m/z 134峰强度较大。m/z 108与m/z 106离子的前体离子可以是偶电子离子m/z 109(邻苯二酚离子)和m/z 107(2-羟基环戊二烯离子),也可以是奇电子离子m/z 134。m/z 108与m/z 106离子来自于偶电子离子时,m/z 109的O—H键直接发生均裂,m/z 107离子的O—H键经过渡态发生均裂。

超高效液相色谱-四极杆-飞行时间质谱法鉴定黄大茶化学成分

黄大茶是中国特有的茶叶品种,具有降脂、降糖、改善代谢综合征的保健功效,但由于缺乏对黄大茶化学成分的研究,其功效性物质基础尚未被完全揭示。本研究以超高效液相色谱-四极杆-飞行时间质谱(UPLC-Q TOF/MS)作为检测工具,结合中性丢失和特征碎片离子等信息,对黄大茶的主要化学成分进行筛查和分析。选取Waters ACQUITY UPLC BEH C18色谱柱(100 mm×21 mm,17μm)进行分离,以01%甲酸水和乙腈作为流动相进行梯度洗脱,流速02 mL/min,进样量2μL,柱温35℃。在电喷雾电离(ESI)正/负离子模式下,利用全信息串联质谱(MSE)技术采集黄大茶样品溶液的质谱信息。通过查阅文献构建茶叶化学成分数据库,主要包括化学名称、分子式、结构式、准分子离子、碎片离子等信息,对自建数据库中的化学成分按照骨架结构进行归类;基于UPLC-Q TOF/MS测定结果,利用对照品对主要类别化合物的质谱裂解规律进行梳理,并总结其特征碎片离子和中性丢失特征;结合化合物的保留时间、准分子离子、碎片离子等信息对化合物结构进行表征。本研究共从黄大茶中鉴定出87个化学成分,包括10个儿茶素类、32个黄酮类、16个酚酸类、12个鞣质类、6个茶黄素类以及11个其他类别化合物,其中14个成分经对照品予以验证。该方法能够全面阐明黄大茶的主要化学成分,为黄大茶功效性成分发现、品质评价提供科学依据和数据支撑。

三氯蔗糖ESI正模式中加钠离子[M+Na]^(+)的特征碎片结构分析研究

分析三氯蔗糖在ESI正模式中[M+Na]^(+)的裂解过程,得出裂解路径和产物分子,为建立基于特征碎片结构快速筛查数据库提供参考。通过优化程序及调整流动相等参数,分析三氯蔗糖加钠的前体离子的谱图规律,结合分析特征产物离子的碰撞能量、强度,以及特征中性丢失,确定特征碎片,推测可能裂解路径,最后通过对自然界氯同位素丰度比的计算,验证了所提出的裂解途径和分子式的有效性。在Q1质谱图中主要生成[M+Na]+加钠离子,Q2质谱图中主要生成239 m/z、221 m/z两个产物离子及其他2个次主要离子,而且这两个离子相对丰度高、稳定性好,结合氯同位素在自然界的丰度比进行计算,验证了该推导裂解路径和分子式的存在合理性。结论为三氯蔗糖在ESI正模式下的应用提供了参考,为三氯蔗糖质谱碎裂模式的分析奠定了理论基础。

离子色谱法同时测定贝叶经碎片中5种无机阴离子含量

建立离子色谱法检测贝叶经碎片中5种主要无机阴离子F^(-)、Cl^(-)、SO_(4)^(2-)、NO_(3)^(-)、H_(2)PO_(4)^(-)含量。淋洗液为30mmol/L KOH溶液,等浓度淋洗,流量为1.0 mL/min,5种阴离子的质量浓度在0~100 mg/L内与对应组分的色谱峰面积线性相关,相关系数均不小于0.9996,检出限为0.2482~0.4712 mg/L。对贝叶经样品进行重复性实验,5种离子的相对标准偏差1.49%~4.35%(n=7),加标回收率为96.4%~105.5%。该方法测定结果准确、可靠、操作简单、快速,适用于贝叶经碎片中主要无机离子含量的测定,对贝叶经病害的机理研究有着重要的意义。

Two-dimensional multiplicity fluctuation analysis of target residues in nuclear collisions

Multiplicity fluctuation of the target residues emitted in the interactions in a wide range of projectile energies from 500 A MeV to 60 A GeV is investigated in the framework of two-dimensional scaled factorial moment methodology. The evidence of non-statistical multiplicity fluctuation is found in 160-AgBr collisions at 60 A GeV, but not in 56Fe-AgBr collisions at 500 A MeV, 84Kr-AgBr collisions at 1.7 A GeV, 16O-AgBr collisions at 3.7 A GeV and 197Au-AgBr collisions at 10.7 A GeV.

Isoscaling of projectile-like fragments

In this paper, the isotopic and isotonic distributions of projectile fragmentation products have been simulated by a modified statistical abrasion-ablation model and the isoscaling behaviour of projectile-like fragments has been discussed. The isoscaling parameters α and β have been extracted respectively, for hot fragments before evaporation and cold fragments after evaporation. It looks that the evaporation has stronger effect on α than β. For cold fragments, a monotonic increase of α and ｜β｜ with the increase of Z and N is observed. The relation between isoscaling parameter and the change of isospin content is discussed.

The Distortion of Energy Deposit Distribution of (12)～C Ions in Water

The transport process of 12C ions in water was studied with SRIM code and Geant4 toolkit. The SRIM results indicate that the transverse diffusion of 12C ion beam causes distortion of energy deposit along the beam direction. The distortion becomes more notable as the transverse diffusion increases. The simulation results of Geant4 indicate that the influence of secondary fragments on energy deposit distribution would be the main factor causing the distortion in higher energy range. In the region adjacent to the beam line where the contribution from 12C ions domi- nates, the contributions from secondary fragments are ignorable. The further from the beam axis the region locates, the larger the contributions from secondary fragments, until the contributions from secondary fragments are ignorable. The further from the beam axis the region locates, the larger the contributions from secondary fragments, until the contributions from secondary frag- ments exceed that of 12C. Among all the secondary fragments, the contributions of H, He and B ions are mostly notable. It is also found that some positron-emitting secondary fragments could be very useful for position emitting tomography （PET）.

Helium production from ^84Kr- and ^197Au-emulsion interactions at high energies

The properties of the relativistic helium fragments produced in interactions of ^84Kr at 1.8 A GeV and ^197Au at 10.7 A GeV in emulsion are investigated. The experimental results are compared with those obtained from various projectiles with emulsion collisions at different energies. It is found that the multiplicity distribution of helium projectile fragments （HPFs） is well described by the Koba-Nielsen Olesen （KNO） scaling presentation. The second Mueller moment f2 of the HPF multiplicity distribution is independent of the projectile energy for the same projectile, but it is dependent on the projectile mass number. The value of f2 increases with the increase of projectile mass number Ap. The negative value of f2, when Ap 〈 69, means that the emission of HPFs is anticorrelated, but positive value of f2, when Ap 〉 69, refers to that the emission of HPFs is correlated. The non-zero f2 moment in this experiment implies the strong correlation existing between the HPFs.

天然橡胶、异戊橡胶和天然橡胶/异戊橡胶并用胶的鉴定方法

以丙酮为溶剂,对6种天然橡胶和2种异戊橡胶进行抽提,基于天然橡胶与异戊橡胶丙酮抽提浓缩液成分存在差异,选择了天然橡胶生胶、异戊橡胶生胶、天然橡胶硫化胶、异戊橡胶硫化胶和天然橡胶/异戊橡胶并用硫化胶定量分析内标物,此外还采用内标法对丙酮抽提浓缩液进行分析,从而建立了天然橡胶、异戊橡胶及天然橡胶/异戊橡胶并用胶的鉴定方法,最后将该方法应用于送检样品主体成分的鉴定。结果表明,角鲨烷可作为天然橡胶、异戊橡胶和天然橡胶/异戊橡胶并用胶定量分析的内标物;在优选的气相色谱-质谱联用定量分析检测条件下,通过定性分析天然橡胶中的γ-谷甾醇和γ-生育三烯酚,同时结合内标法定量分析硫化胶丙酮抽提浓缩液中特定抗氧剂的含量,可以测定天然橡胶/异戊橡胶并用胶中天然橡胶和异戊橡胶的并用比,其中以质荷比为296的特征碎片离子作为异戊橡胶SKI-3定量分析参照特征碎片离子的偏差为-5%;该鉴定方法对于送检样品主体成分的鉴定结果较好。

Reactivity of N-Methylidenemalonates of 3-Arylaminoindoles and p-Dimethylamino-N-Phenylaniline in the Course of Their Analysis by Electrospray Ionization Mass Spectrometry

The behavior of N-methylidenemalonates of 3-arylaminoindoles and p-dimetylamino-N-phenylanyline (M = ANa) was studied during their analysis with ESI mass spectrometer operated in negative (NI) and positive (PI) ion modes. Anions [A] and both [M + H]+ and [M + Na]+ were recorded under conditions of the NI-ESI and PI-ESI, respectively. The fragmentation processes of [A] and [M + H]+ were found that probably occurred as “insource collusion induced dissociation”. The main paths for [A] proved to be elimination of CO2 and breakage of the N-methylidenemalonate bond. A route [A]- - CO2 - ROH (R = Me or Et) was less expressed and occurred for the indolyl-containing compounds with the NH bond only. Experiments employing heavy water demonstrated the isotope exchange to occur involving the hydrogen atom of this bond. This and other facts evidenced that the last fragmentation included abstraction of just this atom. Quantum-chemical calculations allowed picking out a structure for the product ion from the possible ones. The calculations also indicated that the protonation of M occurred at the anionic oxygen atom of the malonate moiety. The fragmentation of [M + H]+ ions included elimination of two water molecules that was supported by their MS2 spectra. A common feature of the NI- and PI-ESI mass spectra was the presence of oligomeric ions, up to tetramers and trimers for the NI- and PI-ESI ones, respectively. The oligomers were formed by interaction of the corresponding ions with neutral molecules. When ions contained extra hydrogen atoms, they were introduced by hydrolysis.