工业色谱仪的嵌入式系统应用研究

介绍用于国产高性能工业色谱仪上的PC/104嵌入式系统,阐述系统配置选择的特点,及智能处理技术在工业色谱仪上的应用和软件实现。研究实现了在线仪器分析记录控制一体化功能,谱峰参数整定及历史谱图的显示和重处理均由嵌入式系统独立完成,完善的数据通信为DCS系统提供了可靠实时的分析结果。嵌入式系统提高了仪器的性能,在工业现场实用中取得了很好效果。     

DANIEL气相色谱仪常见故障及解决方法

DANIEL气相色谱仪在天然气采气行业使用过程中会出现各种各样的故障,根据多年使用经验,归纳色谱仪的常见故障,并借助色谱仪专用软件MON2000的谱图工具,比较正常运行时的谱图和故障出现时的谱图出峰情况,结合色谱仪分析仪系统的六通阀动作时间、积分时间和出峰时间,来推断故障发生的潜在原因,从而锁定故障点并解决问题,并提供解决方案。     

在线色谱仪在芳烃装置中的应用及改进

针对芳烃装置苯塔出口在线色谱分析仪故障频发、出峰不理想等问题,结合现场实际情况,通过对色谱预处理系统和对色谱仪分析系统的改造,延长了色谱仪正常投投用周期,得到了较为理想的谱图,保障了组分测量准确度.     

用于工业色谱仪数据处理及传输的单片机装置

介绍用于GSP－1工业色谱仪的单片微机装置，实现谱峰处理及其与计算机控制系统的数据传送。所设计的硬件组分和软件结构可用于其它工业色谱仪和成份分析仪器的在线处理的研究。     

EEMs-PARAFAC法分析环境中DOM常见组分简述

溶解性有机质(DOM)广泛存在于自然环境中。三维荧光光谱法(EEMs)可以便捷、灵敏地反映溶解性有机质的丰富信息,但荧光谱图中不同的峰常常互相重叠或掩盖。平行因子分析法(PARAFAC)为识别并解读三维荧光谱图中显示的不同DOM组分提供了支持。EEMs-PARAFAC法识别出环境中的DOM反映在荧光图谱上主要包括类色氨酸T、类酪氨酸B、类腐殖质C、类腐殖质M和未知组分N等几种峰。本文简述了EEMs-PARAFAC法的原理及分析得到的常见组分的性质,并对其在未来研究中的应用进行了展望。     

烃重组汽油与催化重整汽油的PONA分析及其组成对比

烃重组技术和催化重整技术都可以生产高辛烷值汽油调和组分,采用气相色谱PONA分析法对烃重组汽油和催化重整汽油分别进行组成分析,并对数据结果进行对比讨论;PONA分析显示,虽然二者都是芳烃质量分数大于70%的高芳烃含量汽油,但在组成分布上存在明显不同;通过结果判断,烃重组汽油的芳烃集中在C_(8)~C_(10)范围,重整汽油中的芳烃组分宽泛存在于C_(6)~C_(11)范围;PONA谱图表明,在保留时间(60~100)min,重整汽油各组分峰几乎全部为尖锐且分离清晰的芳烃峰,而烃重组汽油谱图类似精制石脑油与重整汽油的峰形叠加,不仅包含重整汽油尖锐峰形的芳烃组分,也包含精制石脑油低矮杂多峰形的非芳烃组分。     

乙烯裂解炉在线色谱仪分析系统的设计与优化

阐述色谱仪分析系统取样器和样品处理系统的结构和功能,针对色谱仪分析系统存在的问题进行改进和优化,解决了色谱仪有效运行时间过低的问题,提高了色谱仪分析数据的有效性。同时降低了仪表故障率和人员工作强度。     

煤制乙二醇系统中亚硝酸甲酯含量测定方法的改进

新乡中新化工有限责任公司200 kt/a煤制乙二醇系统采用羰化、加氢两步法间接合成乙二醇工艺,生产控制中对过程气中亚硝酸甲酯(MN)含量测定的要求较高。实际分析过程中,由于色谱仪自身性能以及取样方式、分析操作等方面的原因,分析结果准确度不高。为此,对测定过程进行了一系列的优化改进:将色谱仪计算方法由面积归一法改为外标法,改进仪器标定方式,改进色谱仪以使亚硝酸甲酯与二甲醚出峰分离(色谱峰不重叠),在仪器设备及操作等方面进行优化。改进后,不仅提高了亚硝酸甲酯含量测定结果的准确度,而且保证了色谱仪的安全、稳定、长周期运行,助力了乙二醇系统的高产稳产。     

宽量程气体中形态硫分析色谱仪的设计与应用

焦炉煤气制甲醇，LNG项目中都存在硫化物组分浓度差异大的问题，因此有必要设计一种宽量程形态硫分析色谱仪。采用多色谱分离柱、配双检测器（TCD+FPD），气路切割技术与多通道阀的结合，将高低浓度的样品分别切换到FPD检测器系统和TCD检测器系统进行分离检测，两个通道的谱图数据进行外标法定量计算。该气体硫色谱仪操作简便，可对各种工业气体中硫化物实现快速、准确、宽量程检测分析。     

浓缩气相色谱法测定液氧中微量杂质烃含量

论述了在备有浓缩柱的色谱仪上进行样品的浓缩和分离,采用外标法分析液氧中微量的C1—C4气体烃类,利用WL-95色谱工作站采集谱图和数据处理。该方法灵敏度较高,适用于大气和液氧中烃杂质含量分析。     

The Instrument Spreading Correction in GPC. II. The General Shape Function Using the Fourier Transform Method with a Nonlinear Calibration Curve

Abstract

The instrument spreading function suggested in Part I of this series is investigated for use with the Fourier transform method for generating corrected elution volume chromatograms. The instrument spreading parameters are obtained using linear theory on narrow molecular weight distribution standards, as indicated in Part I. The corrected chromatogram is then combined with a nonlinear molecular weight calibration curve which was fit with a function suggested by Yau and Malone to generate true values of the number- and weight-average molecular weights.

The instrument spreading function is shown to qualitatively and quantitatively describe the dispersion, skewing, and flattening effects ordinarily found in GPC chromatograms due to imperfect resolution by the GPC columns. The Yau-Malone function is shown to be a very useful function for fitting nonlinear molecular weight vs elution volume calibration data. Although the Fourier transform method is shown to work well with analytically generated data, it is shown that a number of numerical problems must be overcome before it can quantitatively produce corrected elution volume chromatograms. Some of these numerical problems are discussed.     

Method of calculating molecular weight distribution function from gel permeation chromatograms. II. Evaluation of the method by experiments

The calculation scheme for correcting the broadening effect due to imperfect resolution on gel permeation chromatograms was compared with actual performances of a gel permeation chromatography (GPC) column. The experiment consisted of fractioanting a high-density polyethylene on a GPC unit and then determining the chromatograms of the cuts collected. The chromatograms of the cuts were also computed from the starting chromatogram using experimentally determined resolution factors. The degree of agreement between the calculated and experimental chromatograms of the cuts shows convincingly that the previously proposed calculation scheme is satisfactory for the treatment of GPC data.     

BAND SPREADING MODELING ANDCORRECTION IN SIZE EXCLUSION CHROMATOGRAPHY NEW METHODS FOR BAND SPREADING PART II CORRECTION

The evaluation of the band spreading corrected chromatogram (the “ideal” chromatogram) from the observed one knowing the shape of single component chromatograms (described by the dispersion function) requires the solution of a Fredholm's integral equation of the first kind (Tung's equation), a mathematically ill-posed problem if details of the unknown chromatogram are sought at a scale narrower than that of single component chromatograms

Most often, chromatogram deformation by instrumental spreading is not too severe and a correction method can be implemented which is based on a Taylor's series expansion. Such a method is proposed in the present paper. The correction is expressed as a function of the derivatives of the observed chromatogram and of the moments of the dispersion function, with an appropriate truncation. The derivatives are calculated from a polynomial approximation of the observed chromatogram which is fitted at each point. Numerical simulations show that the method withstands the problems caused by noisy data and can be applied to any shape for the dispersion function, not necessarily translation-invariant. The Taylor's series method can also be generalized to encompass the analysis of oligomers. Its simplicity and flexibility make it a candidate for widespread use in current analytical practice.     

A Computer Simulation of Linear Gel Permeation Chromatography

Abstract

A phenomenological model based on a set of partial differential equations and boundary conditions is proposed for chromatography and, in particular, for gel permeation chromatography. The intractable boundary value problem, which does not have a closed form solution, was handled through the use of numerical methods employing a very large and very fast computer (IBM 360/195). The chromatograms generated by the computer simulator were compared with experimental chromatograms of various molecular weight polymers. The computer generated overlay plots of the simulated and experimental chromatograms showed good agreement (the two plots almost superimposed). The effect of other parameters on the chromatogram, i.e., flow rate, stationary phase bead size, solute diffusion coefficient in the stationary and mobile phases, and the partition coefficient were also investigated.     

On the selectivity of adsorption chromatography

In this paper, the shape of chromatograms obtained by elution of copolymers with a mixture of solvent-nonsolvent of variable composition has been studied from a theoretical point of view. It is assumed that the thermodynamic quality of the mixture at which the copolymer is eluted depends only on its composition and not on its mass and structure. If one characterizes the polydispersity in composition, assuming that each constituent obeys a molar mass distribution of the Zimm–Schulz type, one can draw the following curves: concentration of the copolymer versus eluant composition. They depend on three parameters, including composition of the copolymer and the polydispersity of each constituent. The most striking result is that the shape of the chromatogram changes dramatically when one increases the polydispersity of either constituents. For low polydispersities, one obtains a classical peak. For large polydispersities, the chromatogram has a minimum for the intermediate values of composition and presents peaks in the vicinity of the pure homopolymers. This can be explained easily by a qualitative argument. © 1996 John Wiley & Sons, Inc.     

从GPC图谱探讨兰州石化丁腈橡胶的质量

比较了兰州石化丁腈橡胶N41、N32、N21与国内外同系列NBR的GPC图谱，并结合产品的性能对比，认为兰州石化橡胶能满足市场对橡胶的性能要求。     

Identification of sterols and bile acids by computerized gas chromatography-mass spectrometry

In mass spectrometry, sterols and bile acids form fragment ions characteristic of certain steroid structures. After separation of derivatized sterols or bile acids by the gas chromatograph and fragmentation in the mass spectrometer, data collected by the computer can be collated to provide a reconstructed gas chromatogram and a series of fragment ion current chromatograms in which the relative abundances of characteristic fragment ions are plotted vs time or scan number. Intensities of these fragment ions will be greatest and hence coincide with peak elution of unidentified sterols or bile acids. The use of known amounts of labeled appropriate sterols or bile acids permits quantitation of the identified sterol or bile acid.     

Correlation of gas chromatographic profiles and organoleptic scores of different fats and oils after simulated deep fat frying

Five oils and a fat were subjected to simulated deep fat frying using moist cotton balls. The used oils were evaluated by an expert organoleptic panel. Statistically significant differences were found in the odors and flavors of the used oils. Volatile decomposition products of the used oils were quantitatively isolated by high vacuum cryogenic entrainment and then analyzed by gas-liquid chromatography. The volatiles from each used oil yielded a gas chromatogram which was qualitatively and quantitatively different from the others. A statistical analysis was used to correlate the organoleptic scores with the profile gas chromatograms from the used oils. Excellent correlations between gas chromatographic peak areas and organoleptic scores were established. However, limitations in the number of samples tested and limitations in the statistical design do not permit drawing conclusions of cause and effect. Paper of the Journal Series, New Jersey Agricultural Experiment Station, Cook College, Rutgers, The State University of New Jersey. Presented at the 47th Fall Meeting of the AOCS in Chicago, September 1973.     

Process gas chromatography of fatty acid distillation streams. II. Design and construction of the process chromatograph

When applied to fatty acid process chromatography, conventional instrumentation is inadequate because of the temp required for effective vaporization of the sample. The instrument described uses a special injector operating at 300C for analysis of distillate streams containing fatty acids C₆ through C₁₈. Tape programmed operation presents analytical data as a chromatogram or as digital printout of electronically integrated peak areas. Details of construction are discussed together with some design problems. AOCS Bond Award, Fall 1964.     

A Technique for Rapid Gas Chromatography Analysis Applied to Ambient Organic Aerosol Measurements from the Thermal Desorption Aerosol Gas Chromatograph (TAG)

While automated techniques exist for the integration of individual gas chromatograph peaks, manual inspection of integration quality and peak choice is still required due to drifting retention times and changing peak shapes near detection limits. The feasibility of a simplified method to obtain multiple bulk species classes from complex gas chromatography data is investigated here with data from the thermal desorption aerosol gas chromatograph (TAG). Chromatograms were divided into many “chromatography bins” containing total eluting mass spectra (both from resolved species and unresolved complex mixture [UCM]), instead of only integrating resolved peaks as is performed in the traditional chromatography analysis method. Positive matrix factorization (PMF) was applied to the mass spectra of the chromatography bins to determine major factors contributing to the observed chemical composition. PMF factors are not highly sensitive to the specific PMF error estimation method applied. Increasing the number of chromatography bins that each chromatogram was divided into improved PMF results until reaching 400 bins. Increasing the number of bins above 400 does not significantly improve the PMF results. This is likely due to 400 bin separation providing bin widths (4.6 s) that match the narrowest peak widths (4.8 s) of compounds found in the TAG chromatograms. The bin-based method took only a small fraction of the time to complete compared to peak-integrated method, significantly saving operator time and effort. Finally, high-factor solutions (e.g., 20 factors) of bin-based PMF can separate many individual compounds, homologues compound series, and UCM from chromatography data.

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