一种新的汽油辛烷值的气相色谱测定方法

建立了一种新的气相色谱结果关联计算汽油辛烷值的方法。采用高分辨毛细管柱对汽油的组成进行测定,根据汽油单体烃组分的含量和纯组分辛烷值乘积的大小,将单体烃组分分为两组,每一组为一个变量,建立实测辛烷值与两个变量间的回归模型。实际分析时,根据不同的样品类型选择不同的模型进行关联计算即可获得色谱分析样品的辛烷值。对模型建立和应用过程中已知结构的化合物的辛烷值数据采用文献值。对只知碳数和类型而不能确定其化合物结构的组分,通过对文献数据进行统计计算,得到平均辛烷值与组分的碳数和类型的关系曲线,据此得到其平均辛烷值用于计算。与采用标准方法测定催化裂化汽油辛烷值的结果相比,该方法测定辛烷值的偏差约0.5个单位。该方法操作简单,用样量少,模型建立过程快速、简便,适合于微型反应器产物评价或炼厂稳定工艺装置的汽油辛烷值的监测。     

国内简讯

叠式固定床离子交换废水净化器研制成功最近上海自动化仪表一厂和上海除尘设备厂联合开发研制成功一种新型“组合式叠床离子交换废水净化装置。”该装置己在上海自动化仪表一厂以及山东,河南等单位使用,效果良好,受到了欢迎。该装置是根据固定床和移动床离子交换装置的某些优点综合设计研制的。整套装置由水泵、流量计、过滤柱、上下两根交换     

汽油辛烷值的介电谱技术测定

利用介电谱仪采集汽油样品介电谱数据,基于已知辛烷值(研究法和马达法测定)的校正集样品,采用偏最小二乘法(partial least squares, PLS)建立校正模型,然后利用所建模型定量预测验证集汽油样品辛烷值(研究法和马达法测定).所建定量模型对验证集样品预测结果的绝对误差:研究法辛烷值不超过0.7个单位,马达法辛烷值不超过0.5个单位.并对介电谱技术的相关关键技术问题进行了讨论分析.研究结果表明:介电谱技术作为一种新的汽油辛烷值快速测定方法可行并具有较好的应用前景.     

基于单体烃分析的辛烷值测定方法中模糊聚类技术的应用研究

介绍了一种应用模糊聚类技术构建辛烷值预测模型的新方法。该模型用来由汽油单体烃数据预测汽油辛烷值,通过提取单体烃分析谱图中的140个工艺特征组分以及对辛烷值贡献大的组分为特征值进行模糊聚类。实际应用时,在待测汽油样品共同参与聚类的条件下,用与待测汽油样品为同一类、并有最小欧氏距离(<1.5)的3~10个样本作为构建辛烷值预测模型的样本。这种按新的建模样本选择方式得到预测模型的方法具有更好的辛烷值预测精度、更广的适用范围和更高的数据资源的利用率。     

自动化样品预处理的一项新技术──吉尔森ASTED系统及其应用（待续）

吉尔森ＡＳＴＥＤ自动化样品预处理系统将膜透析和痕量富集技术结合在一起作为高效液相色谱法分析前的在线样品预处理装置。系统具有简单、快速、重现性好的特点，特别适用于生物样品和食品的预处理。     

自动化样品预处理的一项新技术──吉尔森ASTED系统及其应用（待续）

 吉尔森ＡＳＴＥＤ自动化样品预处理系统将膜透析和痕量富集技术结合在一起作为高效液相色谱法分析前的在线样品预处理装置。系统具有简单、快速、重现性好的特点，特别适用于生物样品和食品的预处理。     

基于脉冲直流电喷雾离子化的自动化原位质谱分析系统及其应用

脉冲直流电喷雾离子化质谱（PDESI-MS）分析具有原位、实时、快速和可分析微量样品等优点。然而，目前的PDESI-MS系统需手动操作进行样品处理和质谱进样，存在操作繁琐、步骤多、误差大和准确度低等问题。本工作研制了一套高通量、全自动化和一体化的PDESI-MS系统，探索了其在真核生物（单个膀胱癌细胞）和原核生物（细菌单菌落）中小分子代谢物原位检测分析中的应用。结果表明，本自动化PDESI-MS系统可有效检测不同菌种代谢物，实现了不同类型大肠杆菌的分类定型；同时，皮升级液滴产生技术使其可应用于单细胞检测。自动化PDESI-MS系统可实现高精度、高密度、高重复度和高自动化的原位样品萃取，特别是微量小体积样品的分析，在食品安全、再生医学、药物筛选和临床治疗等领域具有极大的应用潜力和良好的发展前景。     

国家“十五”科学仪器攻关重大项目子课题“全自动多路加温加压快速溶剂萃取仪（APSE）”通过验收

样品分析过程包括取样、样品制备与处理、分析测定、数据处理、总结报告等五个部分，通过统计发现样品处理所需时间占整个分析过程的61％，而分析测定的时间仅占6％。目前实验室所采用的样品前处理技术主要为传统的索氏提取、液．液萃取、微波萃取和超临界流体萃取等，这些技术耗时长，萃取效率低。发展高效快速的样品制备与自动化的前处理技术已成为现代分析化学研究的一个重要方向。     

半导体制冷干燥装置在气相色谱法测定溶解态N2O中的应用

结合半导体制冷技术，建立了一种气相色谱在线除水方法，该法具有节约载气、减少干燥剂用量、样品消耗量小等优点。采用该装置，气相色谱法测定溶解态N2O，可有效消除水汽的干扰，仪器连续运行15h基线漂移的变异系数优于0．6％。     

顶空-固相微萃取-毛细管气相色谱-质谱联用方法快速分析香精中挥发性化学成分

通过在香精样品中加入饱和NaCl溶液,建立了适合香精样品直接自动化分析的顶空一固相微萃取一毛细管气相色谱-质谱联用分析方法。采用保留指数检索对质谱检索结果进行进一步的确认,以提高对挥发性成分定性分析的准确性。结果表明：香精中主要含有茴香脑(42．4％)、丁子香烯(5．5％)和β-石竹烯(4．3％)。该方法的精密度为4．0％～8．9％。     

Flow-Batch Analyzer for the Chemiluminescence Determination of Catecholamines in Pharmaceutical Preparations

A novel, simple, cheap, flexible, versatile, and highly sensitivity flow-batch analyzer (FBA) with chemiluminescence detection was developed for determination of dopamine, norepinephrine, and epinephrine in pharmaceutical preparations. The method was based on the inhibitory effect of the mentioned catecholamines on a luminol-potassium hexacyanoferrate (III) chemiluminescence system in alkaline medium. The optimization of the chemical variables affecting this chemiluminescence inhibition effect has been carried out using a Box-Behnken experimental design. The sample throughput was 28 h^?1. The system allowed the automatic preparation of standard solutions and analytical process can be accomplished just by changing the operational parameters in FBA control software.     

High energy resolution Auger spectroscopy on a CMA instrument

An experimental method that increases the analyzer resolution of cylindrical mirror analyzer CMA‐based Auger spectrometers is described. By means of electrically biasing the sample, the effective energy resolution obtainable from the CMA instrument is improved from the native 0.5 to 0.1% or even better for higher kinetic energy Auger transitions. In addition, the maximum kinetic energy Auger transition observable by the CMA Auger instrument is increased from 3200 to 5700 eV, in the current realization. It is also shown that the sensitivity of the energy scale calibration to sample working distance with respect to the analyzer is simultaneously reduced, making the method suitable for chemical surface analysis. The biasing is accomplished using a special sample holder with electronics and software that can be added to an existing instrument. The overall capability of the Auger instrument for chemical analysis is, therefore, increased, while preserving all the analytical functionality and features of the CMA. Copyright © 2011 John Wiley & Sons, Ltd.     

Development and Characterization of A Linear Matrix-assisted Laser Desorption Ionization Mass Spectrometer

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is an important analytical technique for biological macromolecules, such as proteins, peptides and nucleic acid, especially in the field of microbial identification. On the basis of previous study, a linear MALDI-TOF MS was been designed and assembled for biological applications. The instrument comprised a vacuum system, a vacuum fast sample introduction system, an optical system, a time-of-flight mass analyzer, an ion source, a data acquisition system and an electronic control system. The ion source adopted two-stage source acceleration, delayed extraction and dynamic pulse focusing technique. The time-of-flight distance of field-free drift region was about 1 m. The optical system adopted a solid-state laser with adjustable frequency of 1–2000 Hz and spots of 20–100 μm. The angle of incidence laser was controlled at 5°. A series of experiments were carried out to further evaluate the instrument performances. It could not only analyze the samples more than 199 kDa, but also achieve isotope resolution at 1000–3000 Da and up to 900 (FWHM) at 5000–17000 Da. The minimum detectable concentration of gramicidin was 10 amol μL^?1, absolute sensitivity reached up to 2.56 amol. Independent detection of saliva samples from different targets showed that the instrument had higher producibility. We identified Escherichia coli and Shigella spp., which are two common bacteria but difficult to be differentiated by mass spectrometry, showing its potential identification for clinical microorganism. In summary, this instrument can play a role on clinical examination in the near future.     

Development and validation of an isotope-dilution electrospray ionization tandem mass spectrometry method with an on-line sample clean-up device for the quantitative analysis of the benzene exposure biomarker S-phenylmercapturic acid in human urine

An isotope-dilution electrospray ionization tandem mass spectrometry (ESI-MS/MS) method with an on-line sample clean-up device, for the quantitative analysis of human urine for the benzene exposure biomarker S-phenylmercapturic acid (SPMA), was developed and validated. The sample clean-up system was constructed from an autosampler, a reversed-phase C18 trap cartridge, a two-position switching valve, and controlling computer software and hardware. The sample clean-up system was interfaced via 1/20 splitting to the ESI source of a triple-quadrupole mass spectrometer using negative ion mode and multiple reaction monitoring for SPMA and the isotope-labeled internal standard. A strategy was adopted to acquire pooled blank urine matrix and quality control samples spiked with standards. Validated procedures and data on method specificity, detection limits, standard curves, precision and recovery, sample storage stability, and inter-laboratory comparison are presented. The analytical system was fully automated. No tedious manual sample clean-up procedures are required. With the selectivity and the sensitivity provided by ESI-MS/MS detection, the analytical system can be used for high-throughput and accurate determination of SPMA levels in human urine samples, as a biomarker for environmental as well as occupational benzene exposure.     

Raman-STM联用系统及其初步实验

研究固／液界面体系的传统方法主要以电信号为激励和检测手段，已不能适应日益扩大的研究对象和深入至微观研究的要求，许多采用电子束或离子束作为人射源的表面技术由于x作在高真空条件下也难以原位（insitu）研究固／液体表由于光束容易穿过团／液体系的溶液层或具有光学透明的固体电极材料，八十年代以来以光（尤其是激光）作为激励和检测手段的研究方法日益受到重视[1]，目前已开展的工作包括光电流（电压、电容）谱、光发射电流话、光声（热）谱、反（透）射谱、全息谱、瑞利散射、（超）拉曼散射、二次谐波（SHG）以及和频（SFG）…     

Portable Analyzer for Rapid Analysis of Total Protein, Fat and Lactose Contents in Raw Milk Measured by Non-dispersive Short-wave Near-infrared Spectrometry

A novel portable analyzer for raw milk quality control during the material purchase at dairy plants was developed, by which the percentages(mass fraction) of main components including total protein, fat, and lactose of an unhomogenized milk sample could be determinated in 1 min with the help of non-dispersive short-wave near-infrared (NDSWNIR) spectrometry in a wavelength range from 600 nm to 1100 nm and multivariate calibration. The analyzer was designed with a single-beam optical system, which comprised a temperature control module, a multi-channel narrow-band light source(16 wavelengths), a glass absorption cell with 15 mm sample thickness, a silicon photodiode detector, several compound lenses and a recorder module. A total of 80 raw milk samples were collected at a dairy farm twice a month for 4 months. The samples were scanned with a common UV-Vis-NIR spectrometer and analyzed according to China GB standard methods. The uninformative variables elimination(UVE) method was carried out on the spectrum data and the percentages of main components of all the samples to choose the peak emitting wavelength of each channel of the light source. Another 90 raw milk samples were collected from the same dairy farm thrice a month for 3 months. The samples were analyzed according to China GB standard methods and with the proposed analyzer. The percentages of the main components and the NDSWNIR absorption data of the samples were used for the construction and validation of the multivariate calibration model with partial least squares(PLS) method. The root-mean-square errors of prediction(RMSEP) of total protein, fat and lactose were 0.201, 0.172 and 0.247 and the coefficients of correlation(R) were 0.932, 0.981 and 0.933, respectively.     

Portable automated separation system for routine purification and/or pre-concentration of radionuclides based on column chromatography

In recent years the purification and/or pre-concentration of radionuclides before the measurement has grown increasing interest in analytical chemistry. In this study, a new compact and portable stand-alone equipment permitting automatisation of various separation tasks is developed. The new system allows performing quick and reliable automated separation of the selected radionuclide. Since there is no need for permanent manual control of the separation procedures (automatic loading of the sample, washing and stripping solution on the column are controlled via a computer program) the system can be operated overnight. The new system posses the possibility of more variable control for the separation process via new developed user-friendly software, is shielded against the chemical vapors and could be universally equipped with any available chromatographic column. For the automated separation of U, Pu and Am isotopes (achieved recoveries were in the range of 65–95 %, depending on the element separated. The data, presented, show that the application of the module should be also straightforward for other elements: simply by changing the chromatographic columns with the resin having high chemical selectivity for the target ion. The developed separation column module, software and hardware can be readily adapted in any laboratory to meet defined analytical requirements.     

Two-dimensional supercritical fluid chromatography/mass spectrometry for the enantiomeric analysis and purification of pharmaceutical samples

A new analytical two-dimensional supercritical fluid chromatography/mass spectrometry system (2D SFC/SFC/MS) has been designed and implemented to enhance the efficiency and quality of analytical support in drug discovery. The system consists of a Berger analytical SFC pump and a modifier pump, a Waters ZQ 2000 mass spectrometer, a set of switching valves, and a custom software program. The system integrates achiral and chiral separations into a single run to perform enantiomeric analysis and separation of a racemic compound from a complex mixture without prior clean up. The achiral chromatography in the first dimension separates the racemate from all other impurities, such as un-reacted starting materials and by-products. Mass-triggered fractionation is used to selectively fractionate the targeted racemic compound based on its molecular weight. The purified racemate from the achiral chromatography in the first dimension is then transferred to the chiral column in the second dimension to conduct the enantiomeric separation and analysis. A control software program, we coined SFC2D, was developed and integrated with MassLynx to retrieve acquisition status, current sample information, and real time mass spectrometric data as they are acquired. The SFC2D program also monitors the target ion signal to carry out mass-triggered fractionation by switching the valve to fractionate the desired peak. The 2D SFC/SFC/MS system uses one CO(2) pump and one modifier pump for both first and second dimension chromatographic separations using either gradient or isocratic elution. Similarly, a preparative 2D SFC/SFC/MS system has been constructed by modifying an existing Waters preparative LC/MS system. All components except the back pressure regulator are from the original LC/MS system. Applications of the 2D SFC/SFC/MS methods to the separation and the analysis of racemic pharmaceutical samples in complex mixtures demonstrated that an achiral separation (in first dimension) and a chiral separation (in second dimension) can be successfully combined into a single, streamlined process both in analytical and preparative scale.     

固相萃取-固相光谱联用仪的构建及其应用于食品中罗丹明B的测定

设计并制造了以膜材料为分离富集介质的固相萃取装置和以漫反射光谱法为测定手段的测定装置相结合的自动化分析仪并应用于测定食品中罗丹明B的含量。该仪器由固相萃取装置、固相光谱测定装置和软件等3个部分组成。样品溶液(调节pH至2.00)负压自动进样,调节真空度在合适的速率下通过滤膜,待测物质富集于滤膜上。滤膜经热风干燥后由积分球在滤膜固相介质表面采集被测物质的漫反射光谱,仪器控制、光谱采集和数据处理直至报告的发出均由软件完成。在分析辣椒样品时,取样品0.500g,用水50.0mL超声提取10.0min,离心后取上清液测定罗丹明B的含量。测定时用混合纤维素膜进行富集,并选择测定波长为546.7nm。罗丹明B的线性范围为5.0~15.0μg·L^-1。分析红茶样品时,将样品用水稀释10倍后进行分析。在红茶的基质下,罗丹明B的线性范围为10.0~30.0μg·L^-1。上述2种样品的回收率为88.0%~108%,测定值的相对标准偏差(n=5)为4.6%~9.3%。