Application of selected ion monitoring to the analysis of triacylglycerols in olive oil by high temperature-gas chromatography/mass spectrometry

The analysis of the triacylglycerol (TAG) composition of oils is a very challenging task, since the TAGs have very similar physico-chemical properties. In this work, a high temperature-gas chromatographic method coupled to electron ionization-mass spectrometry (HT-GC/EI-MS), in the Selected Ion Monitoring (SIM) mode, method was developed for the analysis of TAGs in the olive oil; this is a method suitable for routine analysis. This method was developed using commercially available standard TAGs. The TAGs studied were separated according to their equivalent carbon number and degree of unsaturation. The peak assignment was carried out by locating the characteristic fragment ions having the same retention time on the SIM profile such as [RCO+74]⁺ and [RCO+128]⁺ ions, due to the fatty acyl residues on sn-1, sn-2 and sn-3 positions of the TAG molecule and the [M−OCOR]⁺ ions corresponding to the acyl ions. The developed method was very useful to eliminate the interferences that appeared in the mass spectrum since electron ionization can prevent satisfactory interpretation of spectra.     

圆盘固相萃取-GC/MS/SIM法在水体有机氮磷农药测定中的应用研究

通过有机氮磷农药测定的样品前处理技术圆盘固相萃取、GC/MS的测定技术选择离子跳变扫描SIM的应用研究,建立了水体中有机氮磷的分析测定方法.其方法检出限达到了ng/L级的水平.     

气质联用单离子监测法测定纺织品中1-萘胺和2-萘胺

采用气质联用单离子监测法(SIM)测定纺织品中1-萘胺和2-萘胺，对提取条件进行了优化，采用保留时间和全扫描质谱图定性，特征离子m/z143为监测离子，以其峰面积定量。     

顶空气相色谱质谱法快速测定液体食品中的挥发性酸

建立了一种用于快速测定食品中挥发性有机酸的分析方法.利用顶空技术对样品进行前处理,并与气相色谱质谱联用,用离子选择对11种挥发性有机酸进行定量分析.在优化的实验条件下,方法线性关系良好,线性范围为0.20 ～5 mg/L.11种挥发性有机酸的相关系数均大于0.998 6,检出限为0.000 2 ～35.5 mg/L,比全扫描检出限低1 ～3个数量级.11种挥发性有机酸的回收率为93% ～99%,相对标准偏差均小于10%.该方法简便、快速、重复性好、定性定量准确,适于食品中挥发性有机化合物的检测.     

吹扫捕集-GC-MS-SIM法测定水中微量甲基叔丁基醚

采用吹扫捕集-气相色谱-质谱联用选择离子检测法(GC-MS-SIM)测定水中微量的甲基叔丁基醚,最低检出质量浓度0．05μg/L,相对标准偏差2．4％,样品的加标回收率在94％∽120％之间。     

A Single‐Ion Magnet Based on a Heterometallic CoIII2DyIII Complex

We report a Co^III₂Dy^III complex, which shows single‐ion‐magnet behaviour. AC susceptibility data of this compound reveals the presence of slow relaxation of the magnetization in zero‐field below 15 K. The relaxation barrier is 88 K.     

基于STM32的多网络人防警报终端设计

传统人防警报系统一般采用单一途径触发方式,实时性和可靠性易受限制,据此设计了多种远程方式控制警报的终端,采用STM32作为主控芯片,外围集成包括移动通讯、固话、有线以太网络三种技术途径触发多种警报,三种途径的仲裁采用先到先触发的兼容方式,并给出了终端的架构及内部设计运行原理,充分发挥了不同网络在不同环境下的优势,保障了不期灾害发生时警报的实时快速预警,同时对状态信息进行反馈,经实际使用测试,系统稳定,实时,可靠性强,为破坏性灾害发生时的成功预警提供了一种可靠方法。     

Universal Super‐Resolution Multiplexing by DNA Exchange

Super‐resolution microscopy allows optical imaging below the classical diffraction limit of light with currently up to 20× higher spatial resolution. However, the detection of multiple targets (multiplexing) is still hard to implement and time‐consuming to conduct. Here, we report a straightforward sequential multiplexing approach based on the fast exchange of DNA probes which enables efficient and rapid multiplexed target detection with common super‐resolution techniques such as (d)STORM, STED, and SIM. We assay our approach using DNA origami nanostructures to quantitatively assess labeling, imaging, and washing efficiency. We furthermore demonstrate the applicability of our approach by imaging multiple protein targets in fixed cells.     

Advanced separation methods of food anthocyanins,isoflavones and flavanols

In recent years, increasing knowledge of the positive health effects of food polyphenols has prompted the need to develop new separation techniques for their extraction, fractionation and analysis. This article provides an updated and exhaustive review of the application of counter-current chromatography, high performance liquid chromatography, capillary electrophoresis, and their hyphenation with mass spectrometry to the study of food polyphenols. Flavonoids constitute the largest class of polyphenols, widely spread in the plant kingdom and common in human diet which has been the most widely studied with respect to their antioxidant and biological activities. The main subgroups are anthocyanins, catechins, isoflavones, flavonols and flavones. They are reported to exhibit antioxidant, anti-carcinogenic, anti-inflammatory, anti-atherogenic, anti-thrombotic, and immune modulating functions, among others. Since red fruit anthocyanins, soy isoflavones and flavanols from grapes and teas are currently the most used phenolic compounds for producing new nutraceuticals and functional foods, this review is focused on these three flavonoid groups.