葡萄酒中26种添加剂的高效液相色谱-高分辨质谱筛查法

建立了一种高效液相色谱-四极杆/静电场轨道阱高分辨质谱同时筛查葡萄酒中26种添加剂（包括防腐剂、抗氧化剂、甜味剂和合成着色剂）的方法。葡萄酒经甲醇 水溶液（1∶9,V/V）稀释后,采用超高效C18柱分离,高分辨质谱全扫描模式提取目标化合物的精确质量数,外标法定量。在0.1~5 mg/L范围内,26种添加剂的线性关系良好,线性相关系数均大于0.99。干红葡萄酒和干白葡萄酒基质中,2、4、20 mg/kg 3个添加水平的回收率均在78.5%~118.8%之间,相对标准偏差小于12.7%,定量限为2 mg/kg。该方法的前处理快速、简单,高分辨质谱定量结果的准确度和精密度高,可用于葡萄酒中添加剂的筛查。     

飞行时间质谱的新突破

本文综述了近年飞行时间质谱的最新发展。LECO Corporation高分辨飞行时间质谱仪Citius LC-HRT在2011年Pittcon参展的1000种新产品中脱颖而出,一举夺得最佳新产品金奖。委员会评选理由是Citius LC-HRT不论在分辨率、采集速度、质量准确度、灵敏度以及性能等各方面都无懈可击,实现业界前所未有的指标记录,树立了TOF品质标杆。此系统使用LECO Folded Flight Path（FFP）技术,提供每秒200张谱图的采集速度、分辨率高达100,000的全范围质谱,刷新了LC-TOF市场的性能记录。可使用ESI、APCI、DESI（Desorption Electrospray）等多种离子源作为选择,搭配LECO Citius LC-HRT高性能质谱能力以及经得起挑战的105-106动态范围。当市场上某些用户还在为选择采集速度和分辨率取舍之间,LECO很荣幸的能够提供一套,不论是采集速度、分辨率、质量准确度或动态范围方面都是无妥协的LC-TOF MS产品,是高效能实验室的最佳选择!本文从代谢组学、环境科学、制药工业、食品工业等几个方面综述了LECO Citius LC-HRT高性能质谱的应用。     

基于高分辨质谱的代谢组学分析技术研究进展

代谢组学研究的目标是对生物体系中所有内源小分子代谢物进行全面的定性和定量表征。由于代谢物组成复杂、种类繁多、理化性质各异、且浓度差异大,给分析工作带来了极大的挑战。高分辨质谱因具有高灵敏度、高质量分辨率和质量精度、宽动态范围等优势,已成为代谢组学研究的主流分析工具。本文综述了近5年来基于高分辨质谱的代谢组学分析技术和方法的最新进展,包括微纳液相色谱、多维色谱与高分辨质谱联用、直接进样高分辨质谱、高分辨质谱成像技术及代谢物定性策略等,并对其发展前景进行展望。     

谱图准确度在高分辨飞行时间质谱分析有机炸药中的应用

应用实时直接分析-高分辨飞行时间质谱（DART-TOF MS）对2,4,6-三硝基甲苯（TNT）、环三亚甲基三硝铵（RDX）、环四亚甲基四硝铵（HMX）、季戊四醇四硝酸酯（PETN）四种常见的有机炸药进行精确质量质谱解析,结果表明,即使在高质量精度的质谱上也不能获得化合物唯一的分子式。借助MassWorks软件对飞行时间质谱数据进行噪音过滤及峰形校正处理,可大大改善高分辨飞行时间质谱对目标化合物分子式识别的准确度,提高定性的准确性,为高分辨质谱解析未知化合物提供参考     

香水中邻苯二甲酸二乙酯的直接质谱分析研究

建立了香水中邻苯二甲酸酯的快速检测方法。采用电喷雾萃取电离技术（EESI）对5种不同品牌香水中邻苯二甲酸二乙酯(DEP)进行了快速直接质谱分析。结果表明：电喷雾萃取电离质谱（EESI-MS）法能够定性定量分析香水中DEP,线性范围为20~1 000 μg/L,线性相关系数R²为0.988 9,检出限为0.39 μg/L,定量限为5.47 μg/L,回收率为94.8%~103.4%,相对标准偏差为1.5%~4.1%。该方法具有检出限低、准确度高、分析速度快（单个样品的测定时间小于30 s）、无需复杂的样品预处理等优点,可为香水中邻苯二甲酸酯的快速检测提供方法参考。     

UPLC－MS／MS同位素内标法测定食品中对位红、苏丹红I－Ⅳ的研究

建立了食品中对位红、苏丹红I～Ⅳ的超高效液相色谱-电喷雾串联质谱测定方法,并采用氘代苏丹红作为同位素内标进行定量。样品经提取、液液萃取和固相萃取（Waters OasisMAX）净化,用超高效液相色谱分离后,采用电喷雾串联质谱进行定性和定量检测。线性范围为O～100μg·L^-1,线性相关系数r大于0．99,方法的定性检出限均小于1μg·kg^-1（S／N=10）,高、中、低3个浓度水平的加标回收率为78％～112．4％。     

UPLC-MS/MS同位素内标法测定食品中对位红、苏丹红Ⅰ~Ⅳ的研究

建立了食品中对位红、苏丹红I～Ⅳ的超高效液相色谱 电喷雾串联质谱测定方法,并采用氘代苏丹红作为同位素内标进行定量。样品经提取、液液萃取和固相萃取（Waters OasisMAX）净化,用超高效液相色谱分离后,采用电喷雾串联质谱进行定性和定量检测。线性范围为0～100 μg•L^-1,线性相关系数r大于0.99,方法的定性检出限均小于1 μg•kg^-1(S/N=10),高、中、低3个浓度水平的加标回收率为78%～112.4％。     

UPLC-HRMS结合质谱分子网络高通量分析人血浆中的代谢物

本文建立了超高效液相色谱-高分辨质谱（UPLC-HRMS）结合质谱分子网络（MSMN）分析血浆中代谢物的方法。采用Folch方法提取血浆中的代谢物,运用UPLC-HRMS技术同时检测水相和有机相中的多种代谢物。以标准品准确定性的代谢物为种子化合物,采用MSMN筛选与种子化合物质谱特征相似的代谢物,扩展代谢物定性范围,提高代谢物定性效率。将该方法用于人血浆中代谢物的定性分析,共检测到187个代谢物。其中,在水相中定性检测到氨基酸、脂肪酸、糖类等80个代谢物,在有机相中定性检测到107个脂类代谢物,实现了人血浆中多类代谢物的高通量分析。     

微型固相萃取-大体积进样-气质联用法快速测定蔬菜中有机磷的农药残留

利用微型固相萃取（SPE）技术进行样品前处理,采用大体积进样结合气相色谱-质谱（GC-MS）技术同时定性和定量,建立了全扫描（Scan）模式下有机磷农药残留的快速分析方法。结果表明,7种有机磷农药的回收率为71%-118%,最小检测限（LODS）在4.0～20.3μg/kg,该方法前处理简单快速,分析成本低,分析时间短,满足蔬菜中多种有机磷农药残留的快速灵敏检测的要求。     

DART-Orbitrap质谱法快速筛查饲料中磺胺类药物

利用新型离子化技术--实时直接分析(DART)离子源与高分辨质谱Orbitrap联用,建立饲料中非法添加磺胺类药物的快速筛查方法。通过对DART离子化温度、样品检测模式等参数进行探索优化,最终确定饲料经过乙腈-水溶液简单提取,液体筛网模块进样,450 ℃下离子化,Orbitrap高分辨质谱在全扫描模式下定性检测,并进行相关的方法学验证,方法检出限为1.0~4.0 μg/g。该方法前处理简单、检测速度快、定性准确、样品通量大、环保无污染,能满足饲料中非法添加磺胺类药物快速筛查的要求。     

AB SCIEX TripleTOF 5600在蛋白质组学研究中的应用

ABSCIEX公司最新发布了全新的高分辨液相色谱质谱联用系统，TripleTOF5600。这一新产品是在享有盏名的API5500三重四极杆系统和QSTAR Elite（QqTOF）系统这两个技术平台的基础上开发出来的。这一全新的TripleTOF5600高分辨液相色谱质谱联用系统能够对复杂的蛋白质组学样品进行高通量分析，并能同时提供高质量的定性和定量结果。为了评估这款仪器的性能，我们设计了基于纳升液相色谱和TripleTOF5600联用系统的一系列实验。首先，我们应用这一拥有高分辨率、高灵敏度和高质量准确度的系统对酵母细胞裂解物的胰酶消化产物进行了分析。实验中采用了每秒最多采集50幅串联质谱谱图的信息相关采集模式，单次LC-MS／MS实验就鉴定了10，179条独特肽段和1174种蛋白（at 1％global false discoveryrate）。而实际达到了平均每秒54幅串联谱图的采集速度是在单次实验获得如此优异的鉴定结果的决定性因素。此外，我们也对一组含有五种已知蛋白以及部分重同位素标记肽段的样品进行了分析，以检验Triple TOF 5600的定量能力。实验中这五种蛋白质都获得了很高的序列覆盖率，其中进样量仅有1OOamol的Peroxiredoxin1蛋白的序列覆盖率也高达55％。而测试中得到肽段的平均质量偏差仅为1．7ppm，展示了Triple TOF 5600的高质量准确度和稳定性。我们还获得了高度准确的定量结果，充分证明了TrIple TOF 5600能够提供三重四极杆系统级别的定量结果。     

ESQUIRE-LC离子阱LC/MS~n

ESQUIRE-LC离子阱LC/MS~n是将惠普(HP)与布鲁克(Bruker)的尖端技术相结合的高效液相色谱/质谱(LC/MS~n)系统。惠普公司成功的1100系列HPLC和先进的电喷雾电离/大气压化学电离(ESI/APCI)离子源与布鲁克公司最新的多极离子阱MS和MS~n分析器完美结合在一起。ESQUIRE-LC是一种先进的自动化程度最高的液质联用仪。本文是对该仪器的性能特点、技术指标及应用的简要介绍。     

Investigations on pressure dependence of Coriolis Mass Flow Meters used at Hydrogen Refueling Stations

In the framework of the ongoing EMPIR JRP 16ENG01 “Metrology for Hydrogen Vehicles” a main task is to investigate the influence of pressure on the measurement accuracy of Coriolis Mass Flow Meters (CFM) used at Hydrogen Refueling Stations (HRS). At a HRS hydrogen is transferred at very high and changing pressures with simultaneously varying flow rates and temperatures. It is clearly very difficult for CFMs to achieve the current legal requirements with respect to mass flow measurement accuracy at these measurement conditions. As a result of the very dynamic filling process it was observed that the accuracy of mass flow measurement at different pressure ranges is not sufficient. At higher pressures it was found that particularly short refueling times cause significant measurement deviations. On this background it may be concluded that pressure has a great impact on the accuracy of mass flow measurement. To gain a deeper understanding of this matter RISE has built a unique high-pressure test facility. With the aid of this newly developed test rig it is possible to calibrate CFMs over a wide pressure and flow range with water or base oils as test medium. The test rig allows calibration measurements under the conditions prevailing at a 70 MPa HRS regarding mass flows (up to 3.6 kg min⁻¹) and pressures (up to 87.5 MPa).     

基于组合算法改进的谱库检索算法

本工作对Stein和Scott提出的SS组合算法（SS）进行改进,采用Kim等研究得到的权值因子优化该算法中对应的权值因子,并重新分配了加权点积相似度算法和峰比例算法的系数。采用改进的SS组合算法,在NIST 11标准参考谱库（212 961张质谱图）中检索了查询库中的30 932张质谱图,使用气相色谱-质谱联用仪分析了8种不同的化合物样品,并且在NIST 11参考库中检索对应的质谱图。为了评价该算法的性能,分别利用2种组合算法分析查询谱图或实验样品的准确度和相似度。结果表明：与之前的SS组合算法相比,使用本方法后,查询谱图在参考谱库中匹配的准确度平均提高了1.15%,并且查询库中94.45%谱图的相似度得到了提高;通过气相色谱-质谱联用仪得到的样品质谱图在参考谱库中有着更高的命中率,并且谱图的相似度平均提高了3.56%。改进的组合算法能够较好地提高待测谱图在参考库中的准确度和相似度,同时也可以利用这种方法改进以SS组合算法为理论基础的其他算法。     

Hydrostatic ionic liquid-lubricated fluid film bearing for a rotational electron-beam lithography system

Rotational electron-beam mastering (REBM) systems have been studied with the aim of achieving the high data density necessary to facilitate the fabrication of next-generation optical data media, such as holographic storage. This study reports the design and testing of an ionic liquid (IL)-lubricated hydrostatic spindle system comprising an IL bearing, IL supply pump, and ionic magnetic fluid seal; and its outgassing performance under high-vacuum conditions. An inner vacuum chamber pressure of approximately 10⁻⁴ Pa was maintained during rotation of the spindle system. The outgassed products, as measured by a quadrupole mass spectrometer, were primarily generated from the air components in the lubricant IL. The non-repeatable runout in the radial direction, which is an important parameter of REBM accuracy, was 100 nm for a rotational speed of less than 130 min⁻¹. The proposed method can be used for a 100-nm scale REBM device.     

Free spectral range measurement of fabry-perot cavity using frequency modulation

In this paper, we propose a novel method to measure the free spectral range (FSR) of a Fabry-Perot cavity (FPC) using single-frequency modulation (FM) with one electric optical modulator (EOM) and the null method. A laser beam modulated by the EOM, to which a cosine-wave signal is supplied from a radio frequency (RF) oscillator, is incident on the FPC. The transmission light from the FPC is observed and converted to an RF signal by a highspeed photodetector, and the RF signal is synchronously demodulated with a lock-in amplifier (LIA) by referring to the oscillator. We theoretically and experimentally demonstrate that the LIA signal become null with a steep slope, when the modulation frequency equals the FSR under the condition that the carrier frequency is slightly detuned from the resonance of the FPC. The experimental results show that the proposed method has the capability to determine the FSR by the null method with a small measurement uncertainty.     

An efficient setup for femtosecond stimulated Raman spectroscopy

We present an efficient and robust setup for femtosecond stimulated Raman (FSR) spectroscopy with 60 fs and 10 cm(-1) resolution. Raman pulses of 0.5-5 ps are tunable between 450-750 nm with energies 1-10 μJ. Experimental features of the setup, signal processing, and data treatment are discussed in detail to be readily reproduced in other labs. The setup is tested by measuring FSR spectra of stilbene in solution.     

Ion spectrometric detection technologies for ultra‐traces of explosives: A review

In recent years, explosive materials have been widely employed for various military applications and civilian conflicts; their use for hostile purposes has increased considerably. The detection of different kind of explosive agents has become crucially important for protection of human lives, infrastructures, and properties. Moreover, both the environmental aspects such as the risk of soil and water contamination and health risks related to the release of explosive particles need to be taken into account. For these reasons, there is a growing need to develop analyzing methods which are faster and more sensitive for detecting explosives. The detection techniques of the explosive materials should ideally serve fast real‐time analysis in high accuracy and resolution from a minimal quantity of explosive without involving complicated sample preparation. The performance of the in‐field analysis of extremely hazardous material has to be user‐friendly and safe for operators. The two closely related ion spectrometric methods used in explosive analyses include mass spectrometry (MS) and ion mobility spectrometry (IMS). The four requirements—speed, selectivity, sensitivity, and sampling—are fulfilled with both of these methods. © 2011 Wiley Periodicals, Inc., Mass Spec Rev 30:940–973, 2011