分析化学

来源:分析化学 阅读数:72 时间:2019-01-22 14:06:13

Progress of Sonic-Spray Ionization Mass Spectrometry and Its Applications  

 

highlights

本文对声波喷雾离子化质谱技术在生命科学、食品安全、法庭化学、反应监测等相关领域的应用研究进展进行了评述,对其发展前景进行了展望。

 

Abstract

Sonic-spray ionization (SSI) is a previously developed soft ionization technique which does not need auxiliary methods such as voltage, heating, laser, or corona discharge. Spray ionization can be achieved under normal temperature and atmospheric pressure by inputting high-speed gas coaxial within the capillary. As an atmospheric pressure ion source, this technique was widely used as the interface of liquid chromatography-mass spectrometry at the beginning of its development. Based on the principles of sonic-spray ionization, a variety of easy ambient sonic-spray ionization derived techniques have been developed, which can be used for the in-situ, rapid and real-time analysis of samples with little or without any sample pretreatment. In this paper, the principless and characteristics of sonic-spray ionization were elaborated, and the progress of its application in life sciences, food safety, forensic chemistry, reaction monitoring, and other related fields were summarized.

 

Graphical Abstract

Sonic-spray ionization is an ionization technique that relies solely on a high-velocity stream of nebulizing gas coaxial to spray capillary and with no assistance of externally applied ionization energy. In this paper, the principles and characteristics of sonic-spray ionization were elaborated, and the progress of its applications in life sciences, food safety, forensic chemistry, reaction monitoring, and other related fields were summarized.

 

声波喷雾离子化技术无需电压、加热、激光、电晕放电等辅助方式,只需要通入与毛细管同轴的高速气体便可以实现喷雾离子化。本文阐述了声波喷雾离子化的原理和特点,并对其在生命科学、食品安全、法庭化学、反应监测等相关领域的应用研究进展进行了综述。

 

 

 

Research Progress and Application of Ion Funnel Technique

 

highlights

离子漏斗是一种广泛使用的离子聚焦引导技术。此论文对离子漏斗技术的原理、设备优化及质谱应用进行了综述,较全面地总结了近二十年来该技术的发展,内容条理清晰,对于相关领域科研工作者具有较好的参考和借鉴作用。

 

Abstract

Ion funnel is a new-style ion guider which can reduce spatial divergence and energy dispersity of the transmission ions by using radio frequency (RF) electric field to confine the ions radially and the direct current (DC) axial electric field to move the ions toward the exit, and thus it can greatly increase the ion transmission efficiency and improve the sensitivity of the mass spectrometry. Since ion funnel was invented in 1997, it has attracted a close attention of mass spectrometry scientists all over the world. Ion funnel has been used in various kinds of mass spectrometry, and built a bridge with high efficiency ion transmission between low vacuum ionization source and high vacuum mass analyzer. In this paper, the principle, technology development, and application progress of ion funnel are reviewed, and the future prospects are prospected.

 

Graphical Abstract

Ion funnel is a new-style ion guide which uses RF electric field to confine the ions radially and the DC axial electric field to drive the ions toward the exit. It can effectively capture, focus and transmit ions under high pressure, and thus greatly improve the sensitivity of the mass spectrometry. In this paper, the principle, technology development and application progress of ion funnel are reviewed, and the future prospects are prospected.

 

离子漏斗是一种新型的离子导向装置,它通过射频电场对离子的径向束缚和匀强电场对离子的轴向推进,可以在较高的气压背景下高效地实现离子的捕获、传输与聚焦,大幅度提高质谱仪器的检测灵敏度。本文主要对离子漏斗的原理、装置结构改进以及质谱应用进展进行了评述,并对今后的发展和应用前景进行了展望。

 

 

 

Detection of S-palmitoylated Proteins in Mouse Heart Tissue Based on Different Precipitation Methods

 

highlights

本文基于不同沉淀方法对小鼠心脏组织总蛋白中的棕榈酰化蛋白进行标记后,利用链霉亲和素琼脂糖珠对已标记上生物素的棕榈酰化蛋白进行富集,最后进行质谱检测分析,共鉴定出50个棕榈酰化蛋白,并发现丙酮沉淀更适合鉴定抗氧化蛋白,甲醇-氯仿沉淀更倾向于鉴定转运蛋白、受体蛋白及结构蛋白,不同的沉淀方法交叉互补使用可使鉴定结果更加丰富,为以后大规模研究棕榈酰化蛋白质组提供了一个新的优化方向。

 

Abstract

The acyl-biotinyl exchange (ABE) is widely used for detection of S-palmitoylated proteins by replacing palmitic acid with biotin, which is a common method for detecting S-palmitoylated proteins. In this study, the effects of acetone precipitation and methanol-chloroform precipitation on the detection of S-palmitoylation proteins in acyl-biotin exchange method were compared, and the S-palmitoylated proteins in mouse cardiac tissue were analyzed. First, N-ethylmaleimide (NEM) was used to block free sulfhydryls within protein molecules. Then, biotinylation reagent (HPDP-Biotin) was used to label the newly produced cysteine thiols that were resulted from treatment by hydroxylamine (HA) in mouse heart tissue. During the ABE reaction, excess unreacted NEM, HA and HPDP-Biotin were removed by precipitation of the proteins. Then, the S-palmitoylated proteins from heart tissue were labeled with ABE reaction based on different precipitation methods, and the S-palmitoylated proteins labeled with biotin were enriched by streptavidin agarose beads. The enriched proteins were analyzed by mass spectrometry, and 50 S-palmitoylated proteins were identified. Specifically, 23 S-palmitoylated proteins were identified in acetone precipitation assay group, and 37 S-palmitoylated proteins in the methanol-chloroform precipitation assay group were identified. 10 palmitoylated proteins were identified in both groups. The results showed that the combination of different precipitation methods could be helpful for the identification of palmitoylated proteins.

 

Graphical Abstract

Two precipitation methods using either methanol chloroform or acetone for identifying palmitoylated proteins by acyl-biotin exchange protocol were compared, in which extensive use of organic regents is needed to precipitate proteins.

 

比较了ABE法中丙酮沉淀与甲醇-氯仿沉淀两种方法对S-棕榈酰化蛋白检测的影响,并对小鼠心脏组织中S-棕榈酰化修饰蛋白进行整体分析。不同的沉淀方法交叉互补使用可使鉴定结果更加丰富、可靠。

 

 

 

Quantitative Analysis of Main Components of Natural Gas Based on Raman Spectroscopy

 

highlights

本文利用非线性最小二乘法将天然气拉曼光谱分解为七种纯物质组分的拉曼光谱分量和若干个洛伦兹谱峰之和的形式,采用训练样本来建立其它物质相对于甲烷的特征峰面积和对应的浓度之间的模型,从而定量分析天然气中甲烷、乙烷、丙烷、二氧化碳、氮气、氢气和一氧化碳的含量。本方法改善了拉曼光谱在混合气测量中的局限性,对拉曼光谱的实际应用有良好的指导和促进作用。

 

Abstract

Natural gas is composed of methane, ethane, propane, carbon dioxide, nitrogen, hydrogen, carbon monoxide and unknown alkane components of C4 or more (denoted as C4+) after desulfurization and dehydration treatment. The concentrations of the first seven components account for more than 90% of natural gas. When analyzing the natural gas composition using Raman spectral analysis methods, a small amount of unknown alkane components C4+ will have a negative impact on the analytical precision. In this work, a novel method that consists of an automatic decomposition algorithm of Raman spectra and a model for quantitative analysis was developed for the analysis of components of natural gas. The Raman spectrum of a natural gas sample could be decomposed into the sum of the Raman spectra of pure constituents and several Lorentz peaks by a nonlinear least-square optimization algorithm based on a linear additivity of Raman spectra. The concentration of the unknown alkane component C4+ was determined according to the area of the C-H deformation vibration peak which was common for most alkane molecules. Some training samples were used to establish the model between Raman characteristic peak areas and corresponding concentrations for each component. Compared with the existing Raman analysis methods, the new method solved the problem of analyzing natural gas containing unknown alkane components with good stability and accuracy. The experiments showed that the maximum absolute errors of this algorithm for methane, ethane, propane, carbon dioxide, nitrogen, hydrogen, and carbon monoxide respectively reached 0.57%, 0.37%, 0.21%, 0.07%, 0.18%, 0.04%, 0.13%, and the correlation coefficient to gas chromatographic results also reached 0.997, 0.986, 0.991, 0.998, 0.993, 1.000, 0.995, 0.982, respectively.

 

Graphical Abstract

The Raman spectrum of a natural gas sample can be decomposed into the sum of the Raman spectra of pure constituents and several Lorentz peaks which represent the content of the unknown alkane component C4+ by a nonlinear least-square optimization algorithm.

 

本文利用非线性最小二乘法将天然气拉曼光谱分解为七种纯物质组分的拉曼光谱分量和若干个洛伦兹谱峰之和的形式,其中C4以上未知烷烃成分的含量采用各种烷烃分子共有的C-H变形振动峰表示。

 

 

Correlation between Boron Isotope of Coral Acroporaand pH Value of Seawater Surface

 

highlights

自上世纪80年代以来,硼同位素地球化学研究的一个重要方向就是运用海洋生物碳酸盐的硼同位素组成进行海水pH演化历史重建,进而反演大气CO2浓度的演化。这一方法的使用有一系列假设前提条件,其中之一就是假设海水中的硼在进入生物碳酸盐过程中只有B(OH)4进入,而且此过程中不产生或仅有很小的同位素分馏。这一研究方向受到国际同行的极大推崇,也取得了大量的具有影响力的研究成果。然而,随着研究的逐渐深入,研究者发现,上述假设条件不一定成立。

 

近30年来,利用海洋生物碳酸盐(珊瑚、有孔虫)的硼同位素组成重建古海水pH,计算大气CO2含量,进而推测古气候的变化,已成为国际同位素地球化学研究的热点。

 

目前有很多关于生物碳酸盐的11B值与海水pH值相关性的研究报道,而海水中的硼是否只以B(OH)4-形式掺入海洋生物碳酸盐成为目前争论的焦点之一。通过室内珊瑚培养实验可以为以上争论的解决提供有力证据。虽有部分研究进行了室内培养实验,但由于养殖条件很难精准控制及很难辨别珊瑚新生长部分,因此效果不理想。该论文采用串联水循环系统,在保证养殖过程中各水化学参数稳定的情况下,成功解决了养殖珊瑚中新生长珊瑚样品的培植和采集问题。在此基础上,在不同pH条件下进行了珊瑚的养殖实验,探讨了珊瑚硼同位素组成与海水pH值关系,进一步验证了三氧硼同时掺入进珊瑚。根据实验数据获得了珊瑚硼同位素组成与pH的经验方程,为更好地进行海水pH值反演提供了理论支持。该论文还讨论了Mg(OH)2的生成对硼浓度及硼同位素分馏的影响。本研究的结果,对硼同位素地球化学研究具有重要意义。

 

Abstract

A water circulation system with the almost same element composition and socket type was adopted in coral Acropora culture under different seawater pH value conditions and the data of the relationship between boron isotopic compositions of coral and seawater pH value by thermoelectric ionization mass spectrometer were obtained. According to the correlations between αcarb-3 of coral and the pH value of cultured seawater, αcarb-3 was not a constant but related to pH value, indicating that B(OH)3 also incorporated carbonate. Therefore, the theoretical formula could not be used to calculate the seawater pH value from the δ11Bcarb value of the measured marine biological carbonate. The empirical equations obtained experimentally would be an alternative method to calculate the seawater pH value. In addition, the mixed precipitation of CaCO3 and Mg(OH)2 was found in aquaculture tanks with high pH value, and the δ11B of the solid was significantly higher than that of cultured seawater. The result indicated that the presence of Mg(OH)2 had a significant effect on the boron isotope fractionation, which deserved our attention.

 

Graphical Abstract

Water circulation system with the almost same element composition and socket type were adopted in coral Acropora culture under different seawater pH values. The boron isotopic composition of coral was positively correlated with the pH value of seawater and carb-3 was not a constant, indicating B(OH)3 also incorporated carbonate, so the hypothesis of 11Bcarb=11B4 is not valid.

 

在一致的条件下,进行了不同海水pH值环境下的鹿角珊瑚养殖实验。测得珊瑚硼同位素组成与海水pH值呈正相关关系。珊瑚与海水B(OH)3间的硼同位素分馏系数acarb-3与养殖海水pH的关系表明,acarb-3不是常数,而是与pH值有关,表明B(OH)3同时掺入珊瑚生物碳酸盐,说明d11Bcarb=d11B4的假设是不成立的。

 

发布日期:2019/1/25