The collision induced dissociation (CID) of H+2 ion colliding with He target has been measured by Williams andDunbar[1] and Suzuki et al.[2] in the keV energy region. In Ref. [1], the CID cross sections decrease monot...The collision induced dissociation (CID) of H+2 ion colliding with He target has been measured by Williams andDunbar[1] and Suzuki et al.[2] in the keV energy region. In Ref. [1], the CID cross sections decrease monotonouslywith decreasing energy. But the energy dependency of the CID results in Ref. [2] is different with that in Ref. [1].At energies below 1 keV, no experimental results are available for integral cross sections. On the theoretical side,Furlan and Russek[3] have investigated the electron capture (EC), CID and excitation processes in the few keVenergy region. Their calculations are performed by the straight-line trajectory method based on the ab initiomolecular structure. A three-state approximation is employed in their calculations. Their CID cross sections areseveral times smaller than the experimental results. We present the quantum-mechanical molecular orbital closecoupling (QMOCC) calculations[4] for the CID process of the H+2 + He collision.展开更多
Liquid chromatography hybrid ion trap/time-of-flight mass spectrometry possesses both the MS^n ability of ion trap and the excellent resolution of a time-of-flight and has been widely used to identify drug metabolites...Liquid chromatography hybrid ion trap/time-of-flight mass spectrometry possesses both the MS^n ability of ion trap and the excellent resolution of a time-of-flight and has been widely used to identify drug metabolites and determine trace multi-components in natural products. Collision energy, one of the most important factors in acquiring MS^n information, could be set freely in the range of 10%–400%. Herein, notoginsenosides were chosen as model compounds to build a novel methodology for the collision energy optimization. Firstly, the fragmental patterns of the representatives for the authentic standards of protopanaxadiol-type and protopanaxatriol-type notoginsenosides were obtained based on accurate MS^2 and MS^3 measurements via liquid chromatography hybrid ion trap/time-of-flight mass spectrometry. The extracted ion chromatograms of characteristic product ions of notoginsenosides in Panax Notoginseng Extract were produced under a series of collision energies and compared to screen the optimum collision energies values for MS^2 and MS^3. The results demonstrated that the qualitative capability of liquid chromatography hybrid ion trap/time-of-flight mass spectrometry was greatly influenced by collision energies, and 50% of MS^2 collision energy was found to produce the highest collision-induced dissociation efficiency for notoginsenosides. Addtionally, the highest collision-induced dissociation efficiency appeared when the collision energy was set at 75% in the MS^3 stage.展开更多
Phospholipids are the major building blocks of the biological membranes. Additionally, phospholipids modulate membrane trafficking and metabolites derived from their
基金National Natural Science Foundation of China (11004014, 10979007)
文摘The collision induced dissociation (CID) of H+2 ion colliding with He target has been measured by Williams andDunbar[1] and Suzuki et al.[2] in the keV energy region. In Ref. [1], the CID cross sections decrease monotonouslywith decreasing energy. But the energy dependency of the CID results in Ref. [2] is different with that in Ref. [1].At energies below 1 keV, no experimental results are available for integral cross sections. On the theoretical side,Furlan and Russek[3] have investigated the electron capture (EC), CID and excitation processes in the few keVenergy region. Their calculations are performed by the straight-line trajectory method based on the ab initiomolecular structure. A three-state approximation is employed in their calculations. Their CID cross sections areseveral times smaller than the experimental results. We present the quantum-mechanical molecular orbital closecoupling (QMOCC) calculations[4] for the CID process of the H+2 + He collision.
基金supported by the National Nature Science Foundation of China(Nos.81273589,81374054)the Nature Science Foundation of Jiangsu Province(BK20131311)+2 种基金the fundamental research special fund of China Pharmaceutical University(PT2014 YK0081)Jiangsu Provincial Promotion Foundation for the Key Laboratory of Drug Metabolism and Pharmacokinetics(BM2012012)Jiangsu Key Laboratory of Drug Design and Optimization
文摘Liquid chromatography hybrid ion trap/time-of-flight mass spectrometry possesses both the MS^n ability of ion trap and the excellent resolution of a time-of-flight and has been widely used to identify drug metabolites and determine trace multi-components in natural products. Collision energy, one of the most important factors in acquiring MS^n information, could be set freely in the range of 10%–400%. Herein, notoginsenosides were chosen as model compounds to build a novel methodology for the collision energy optimization. Firstly, the fragmental patterns of the representatives for the authentic standards of protopanaxadiol-type and protopanaxatriol-type notoginsenosides were obtained based on accurate MS^2 and MS^3 measurements via liquid chromatography hybrid ion trap/time-of-flight mass spectrometry. The extracted ion chromatograms of characteristic product ions of notoginsenosides in Panax Notoginseng Extract were produced under a series of collision energies and compared to screen the optimum collision energies values for MS^2 and MS^3. The results demonstrated that the qualitative capability of liquid chromatography hybrid ion trap/time-of-flight mass spectrometry was greatly influenced by collision energies, and 50% of MS^2 collision energy was found to produce the highest collision-induced dissociation efficiency for notoginsenosides. Addtionally, the highest collision-induced dissociation efficiency appeared when the collision energy was set at 75% in the MS^3 stage.
文摘Phospholipids are the major building blocks of the biological membranes. Additionally, phospholipids modulate membrane trafficking and metabolites derived from their
文摘蛋白质组学的兴起带动了质谱技术的快速发展,而质谱技术的进步则拓宽了蛋白质组学研究问题的广度.最近10年内,肽段或完整蛋白质在质谱仪中的裂解技术——电子捕获裂解(electron capture dissociation,ECD)与电子转运裂解(electron transfer dissociation,ETD)逐渐发展起来.ECD和ETD在蛋白质组学中的应用,特别是在蛋白质的翻译后修饰鉴定和"自顶而下(Top-down)"的完整蛋白质裂解研究中已经展示出了诱人的前景.对ECD和ETD的基本原理、质谱特点、仪器实现、数据解析算法与软件开发,以及在蛋白质组学中的应用进展等方面进行了比较系统全面的阐述,并对当前的研究问题、面临的技术挑战与未来的发展趋势等方面作了深入剖析.
