质谱

ˆﰀ缘枠ﰅ缘

Abstract(#br)In this study, a novel and efficient method based on headspace solid-phase microextraction (HS-SPME), followed by gas chromatography–mass spectrometry (GC–MS), was developed for the analysis of propolis volatile compounds. The HS-SPME procedure, whose experimental parameters were properly optimized, was carried out using a 100\u003cce:hsp sp=\"0.25\"/\u003eμm polydimethylsiloxane (PDMS) fiber.

Abstract(#br)Megastigmatrienone is a key flavor compound in tobacco.

Abstract(#br)The phosphorylation of proteins is a major post-translational modification that is required for the regulation of many cellular processes and activities. Mass spectrometry signals of low-abundance phosphorylated peptides are commonly suppressed by the presence of abundant non-phosphorylated peptides. Therefore, one of the major challenges in the detection of low-abundance phosphopeptides is their enrichment from complex peptide mixtures. Titanium dioxide (TiO 2 ) has been proven to be a highly efficient approach for phosphopeptide enrichment and is widely applied.

Abstract(#br)The collection of a low vapor pressure chemical simulant triethyl phosphate sorbed onto silica gel (TEP/SG) from a surface with subsequent analysis of the TEP/SG particulates using desorption electrospray ionization–mass spectrometry (DESI–MS) is described. Collection of TEP/SG particulates on a surface was accomplished using a sticky screen sampler composed of a stainless steel screen coated with partially polymerized polydimethylsiloxane (PDMS).

Abstract(#br)Polydimethylsiloxane (PDMS) membranes were synthesised by varying the degree of crosslinking and were characterised in a pervaporation system coupled to a mass spectrometry (MS) for on-line monitoring and collecting data points with an interval of 2\u003cce:hsp sp=\"0.25\"/\u003es. This monitoring approach allows obtaining very precise information about the impact of solutes’ solubilisation within the membrane and their influence on solvent permeation.

A protein digestion system using immobilized enzymes for protein identification and glycochain analyses has been developed, and a vibration reaction unit for micro-scale sample convection on an enzyme-immobilized solid surface was constructed. BSA as a model substrate was digested by this unit, and was successfully identified by mass spectrometry (MS) analyses. Compared to the conventional liquid-phase digestion, the reaction unit increased the number of matched peptides from 9 to 26, protein score from 455 to 1247, and sequence coverage from 21% to 48%.

A protein digestion system using immobilized enzymes for protein identification and glycochain analyses has been developed, and a vibration reaction unit for micro-scale sample convection on an enzyme-immobilized solid surface was constructed. BSA as a model substrate was digested by this unit, and was successfully identified by mass spectrometry (MS) analyses. Compared to the conventional liquid-phase digestion, the reaction unit increased the number of matched peptides from 9 to 26, protein score from 455 to 1247, and sequence coverage from 21% to 48%.

采用色谱分离、光谱和光谱检测等多种分析方法，研究了聚碳酸酯聚二甲基硅氧烷共聚物( PC-co- PDMS )的结构和组成。特别地，利用尺寸排阻色谱( SEC )和液相吸附色谱在不同条件下(如采用梯度溶剂体系)实现了按摩尔质量和功能分布的分离。两种方法的耦合产生了指纹图谱二维图，可以方便地比较不同的共聚物批次。采用基质辅助激光解吸/电离飞行时间质谱( MALDI-TOF )进行结构考察。然而，两种共聚单体的不同电离行为极大地限制了该技术的适用性。与此相反，傅里叶变换红外光谱( FTIR )可用于定量色谱图中不同位置共聚物中PDMS的量。该方法能够区分PC-co- PDMS共聚物和材料中存在的PC均聚物链。

近年来，一种利用开放存取资源进行实验室研究的趋势已经开始。科学硬件的开源设计策略依赖于使用广泛可用的部件，特别是那些可以直接打印的部件，使用可与低成本微控制器连接的可加性制造技术和电子元件。开源软件消除了昂贵商业许可证的需要，提供了针对特定需求设计程序的机会。本综述对化学分离领域内的“开源运动”的影响进行了描述，主要是通过对近5年来该领域的研究进行全面的考察。涵盖的主题包括一般实验室设备、样品制备技术、基于分离的分析、检测策略、电子系统控制和数据处理软件。还讨论了在这些与分离有关的专题中继续存在的障碍和进一步采用开源办法的可能机会。