On-line octane-number analyser for reforming unit effluents. Principle of the analyser and test of a prototype

An on-line automatic explosion-proof process octane-number analyser was developed. The principle is based on on-line capillary gas chromatographic analysis of the sample. A computer program performs the identification and the quantification of the components and calculates the octane numbers and other physical properties. The process analyser consists of laboratory equipment placed in an explosion-proof shelter. A prototype of the analyser was tested on a pilot plant under industrial conditions. It was shown that the fully automated analyser is reliable and reproducible.     

X-ray radiometric analysis of ores and minerals using apparatus based on semiconductor detectors

This paper deals with the evaluation methods of matrix effect in multicomponent X-ray radiometry using a semiconductor spectrometer. These methods consist in measuring the radiation incoherently scattered by a sample. Relationships for the calculation of the element content of interest are given with the use of the predetermined content of an element without considering the matrix effect determined from calibration curves, as well as analytic expressions enabling the automation of the processing of measured results by an electronic computer. Experimental verification of these methods, carried out in this case on the analysis of complex ores (determination of copper, zinc and lead), has shown that analysis errors do not exceed 5% rel.     

An elemental analyser system controller for data-processing of automatic C-H-N analysers

Summary An Elemental Analyser System Controller has been developed for automated data-processing of automatic C-H-N analysers. The elemental analyser system controller allows users, already in possession of a digital voltmeter or integrator, electronic microbalance, calculator and C-H-N analyser, to combine their various pieces of equipment into an automated system. After starting the C-H-N analyser, this system processes all data and calculates the blanks, calibration factors and percentages, successively. The operational modes of the principal parts of the element analyser system controller are described.

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Zusammenfassung Ein Kontrollgerät für Elementaranalysatoranlagen für automatisierte Datenverarbeitung automatischer C-H-N-Analysatoren wurde entwickelt. Bei Vorhandensein eines Digitalvoltmeters oder Integrators, einer elektronischen Mikrowaage, eines Rechengerätes und eines C-H-N-Analysators gibt dieses Kontrollgerät die Möglichkeit, die erwähnten Einzelteile zu einem automatischen System zu kombinieren. Nach Einschalten des C-H-N-Analysators verarbeitet dieses System nacheinander alle Daten, berechnet die Blindwerte, die Eichfaktoren und Prozentgehalte. Die Arbeitsweise der wichtigsten Teile des Kontrollgerätes wurde beschrieben.

     

Zur Steuerung eines Eisenhüttenlaboratoriums durch Digitalrechner

A combination of instrumental systems for issuing measured data with a digital computer for automatic on-line data processing is described. The functions of the computer comprise data conversion, calibration checking of the instruments and recording of the results. Operation of the calibration checking and efficiency of the system are discussed.     

Automation of liquid scintillation data processing

A program was written in the Basic language to handle scintillation counting data by a time-sharing computer. Explanation is given for the use of the program to facilitate the most common types of calculations, as well as the automatic data handling between the spectrometer and the remote computer. The merits of the system are discussed and a sample of the operation and the output is given.     

基体归一定量技术在激光烧蚀-等离子体质谱法锆石原位多元素分析中的应用

探讨了内标法和基体归一法校准的基本原理。基体归一校准法的基本步骤为:先用简单外标法测得样品中尽可能全的主、次、痕量元素含量,氧化物加和后进行100%归一,得到灵敏度校正系数,对所有元素的测定结果进行修正。修正结果的可靠性在很大程度上取决于测定元素是否"完全"。由于锆石的基体元素组成简单且易于测定,很适合用基体归一法校准。在激光剥蚀-电感耦合等离子体质谱法(LA-ICP-MS)微区原位分析中,应用基体归一校准法的最大优点是:可以避免预先用其它微区分析技术对未知样品中的内标元素进行定量。该技术可适用于具有环带结构、难以找到均匀分布的内标元素的地质样品的元素空间分布测定。在高分辨ICP-MS(Element2)和NewWave-UV-213激光系统上,应用基体归一定量技术同时分析了锆石中主、次、痕量共54种元素。对未知锆石样品的分析,基体归一法与内标法结果的一致性令人满意。分析德国蛇纹岩标准玻璃ATHO-G中相对误差<25%的有52个元素,<10%的有36个元素;大多数元素的相对标准偏差<10%。     

A computer program for the collection,reduction and analysis of echelle spectra

This article is an electronic publication in Spectrochimica Acta Electronica (SAE), the electronic section of Spectrochimica Acta Part B (SAB). The hardcopy text, comprising the main article and an appendix, is accompanied by a disk containing the compiled program, a manual, the source code and tutorial in ASCII format, and data files. The work presented is a result of the need to facilitate collection, calibration, and extraction of data from an echelle spectrometer employing charge coupled array detection (CCD). A computer program, written using Microsoft's BASIC Professional Development System version 7.1 under MS DOS, is explained and demonstrated. Wavelength calibration requires critical spectrometer dimensions, grating counter settings, and the identification of a single spectral line. Calibration accuracies are better than ± 1 pixel across a 576 × 384 pixel array. Extraction of intensity-normalized spectra for all detected orders requires less than 3 min on a 33 MHz 80386 personal computer with an 80387 math coprocessor.     

A re-investigation of phenol as a spectrophotometric reagent for the determination of nitrate-nitrogen

The advantages of phenol over isomers of dimethylphenol in the determination of nitrate-nitrogen are described. Linear calibration graphs are obtained for the ranges 0–100, 0–400 and 0–20 μg ml^l-1 for nitrate-nitrogen; these ranges are suitable for analyses of plant materials, soil extracts and waters. For spiked samples, recoveries of 97.7 to 104.3% were obtained with relative standard deviations of 2.0 to 6.7%. Tolerance to chloride is good, and interferences by nitrite and hydrogen peroxide are easily controlled. A modified Markham microstill for use in automatic analyser systems is described.     

The determination of total nitrogen in plant materials with an automatic nitrogen analyser

An automatic analyser is used for the measurement of total nitrogen in chemical compounds and botanical material after the combustion method of Dumas in vacuum. The analyser is described and results for several chemical compounds and plant materials are given. The results have been statistically evaluated to compare the reproducibility and accuracy of the automatic analyser and the Kjeldahl method.     

Primary standards in activation analysis

The availability of natural matrix reference materials evaluated for trace element content has resulted in their widespread use as standards (i.e., calibration materials; comparators) for instrumental neutron activation analysis (INAA). Due to the uncertainties associated with their certified values, the limited number available, and the relative matrix independence of INAA, these reference materials are more properly utilized as quality assessment materials, after calibration of the INAA analytical system with true primary standards. Terminology is defined, the use of matrix reference materials to evaluate the analytical system is discussed, techniques for the accurate preparation of primary standards for trace element analyses are reviewed, and necessary precautions in the accurate comparison of samples to standards are presented.     

Computerized data analysis of amino acids in physiologic fluids.

A Fortran IV computer program is described which identifies, computes, and statistically evaluates amino acid concentrations determined by an automatic amino acid analyzer in physiologic fluids. The program accepts retention time and intergrated peak areas from two calibration standards for identification and computational reference. Two internal standards are used to compensate for variations in injector performance and ninhydrin decay. Calibration standard responses are statistically treated to assist in detection of equipment malfunction. The statistical data base is automatically explanded through inclusion of data from normal patients. Amino acid concentrations are printed with appropriate mean and standard deviation values in a format acceptable as a final report.     

An Experimental Evaluation of a New Commercial Viscometric Detector for Size-Exclusion Chromatography (SEC) Using Linear and Branched Polymers

Abstract

Herein are reported some findings on the application of a new type of continuous automatic viscometer, in parallel with a differential refractometer, as a detector system for SEC. A universal calibration is required for the instrument and two methods of construction are applicable. The first is the customary peak-position calibration using polymer standards of narrow molecular-weight distribution and the second uses a single broad standard of known [Mbar]_w and [Mbar]_n. The two types of calibration are shown to give nearly-identical values of molecular weight when used to process chromatograms obtained from various linear homopolymer standards of varying chemical composition. These values compare favourably with those quoted by the suppliers of the polymer standards. One of the more powerful features of this instrumentation, namely its potential for estimating accurate molecular weights of branched polymers, is demonstrated by analysis of a series of branched polyvinylacetates prepared by a conventional bulk, free-radical polymerisation procedure. The calculation of the degree of chain branching is discussed. Another particular feature of the viscometer detector, its ability to indicate the presence of low concentrations of high-molecular-weight impurity in polymer samples, is also shown.     

Calibration of laser-ablation ICP-MS. Can we use synthetic standards with pneumatic nebulization?

An approach for the determination of trace element concentrations in high purity metals, using an inductively coupled plasma mass spectrometer (ICP-MS) with a laser-ablation system for direct solid sample introduction after calibration with nebulized liquid standards was made. Due to the inherent differences in the rate of sample introduction with laser-ablation and pneumatic nebulization, a matrix element must be used as an internal standard. This is problematical for elements that have no isotope with a relative abundance of less than 0.1 %, since the ion signals would be too high for direct measurement, and reduction of the ablation rate would compromise the sensitivity for trace elements. Due to the high stability of ICP-unit and mass filter of the instrument used, it was found that the tail of a mass-peak of the matrix element could be used as an internal standard. Therefore, a position at –0.5 amu from the matrix-isotope (e.g. ^62.5Cu in copper samples) was used for internal standardization. The standard deviation of this signal in a period of 2.5 h was 3.6% RSD with no notable drift when the laser ablation was used for sample introduction. The calibration of the matrix-element by nebulizing liquid standards showed that the ion signal measured on the peak-tail is directly proportional to the element concentration in the ICP. This indicates that the peak shape is not only stable, but also independent of the peak height. The advantages of this method lie in the easy preparation of calibration standards for quantitative measurements with a laser-ablation system and access to homogeneous standards for materials, that are difficult to homogenize in the solid state. The calibration of the traces is performed relatively to a fixed concentration of the matrix element. Calibrations were carried out for trace concentrations in high purity copper and good recoveries were obtained for high-purity reference standards. Received: 23 February 1998 / Revised: 20 July 1998 / Accepted: 25 July 1998     

Automation of Structure Analysis. Part II. Automation of the Evaluation

The extent to which it is possible to automate the determination of a structure from the data collected with automatic measuring equipment is discussed. The development of the automatic evaluation is synchronous with that of digital computer program.—Even the simple calculation of structure factors from the intensities (i.e. the analysis of the geometrical and physical intensity factors) takes several weeks when the many thousand reflections are processed “manually”, i.e. with a desk calculator. A large electronic computer, on the other hand, executes these calculations in a few seconds. Nevertheless, even the largest computers available at present are too small for many of the complex steps in the calculation and for the quantity of data involved. Evaluation methods which, owing to long computing times, can at present only be tested on relatively simple structures will become more attractive with the advent of machines with computing times in the nanosecond range. For corrigendum see DOI: 10.1002/anie.196605112     

Calibration of laser-ablation ICP-MS. Can we use synthetic standards with pneumatic nebulization?

An approach for the determination of trace element concentrations in high purity metals, using an inductively coupled plasma mass spectrometer (ICP-MS) with a laser-ablation system for direct solid sample introduction after calibration with nebulized liquid standards was made. Due to the inherent differences in the rate of sample introduction with laser-ablation and pneumatic nebulization, a matrix element must be used as an internal standard. This is problematical for elements that have no isotope with a relative abundance of less than 0.1 %, since the ion signals would be too high for direct measurement, and reduction of the ablation rate would compromise the sensitivity for trace elements. Due to the high stability of ICP-unit and mass filter of the instrument used, it was found that the tail of a mass-peak of the matrix element could be used as an internal standard. Therefore, a position at –0.5 amu from the matrix-isotope (e.g. ^62.5Cu in copper samples) was used for internal standardization. The standard deviation of this signal in a period of 2.5 h was 3.6% RSD with no notable drift when the laser ablation was used for sample introduction. The calibration of the matrix-element by nebulizing liquid standards showed that the ion signal measured on the peak-tail is directly proportional to the element concentration in the ICP. This indicates that the peak shape is not only stable, but also independent of the peak height. The advantages of this method lie in the easy preparation of calibration standards for quantitative measurements with a laser-ablation system and access to homogeneous standards for materials, that are difficult to homogenize in the solid state. The calibration of the traces is performed relatively to a fixed concentration of the matrix element. Calibrations were carried out for trace concentrations in high purity copper and good recoveries were obtained for high-purity reference standards. Received: 23 February 1998 / Revised: 20 July 1998 / Accepted: 25 July 1998     

Temporary negative-ion states in pyridine and diazine molecules

Results of electron scattering experiments using a transmission spectrometer are reported for the N-heterocyclic molecules: pyridine, pyridazine, pyrimidine and pyrazine. A number of resonant states are observed in the energy range 0.05 eV to 10 eV. Substituting an N atom for a CH radical in the benzeene ring is shown to remove the degeneracy of the two lowest empty π-orbitals. The derivative technique is applied to the 127° momentum analyser but none of the vibrational structure observed in an experiment using a trochoidal monochromator is detected. Reasonable agreement is reached for values of the first electron affinity.     

Computer-selected optimization of activation analysis methods

The possibilities of using a computer to optimize the conditions of gamma-activation analysis are considered. Criteria of optimum conditions are formulated. The optimization program is constructed of the following operations being automatically performed: (1) determination of a list of isotopes and their gamma-lines formed during the interaction between the activating bremsstrahlung and the substance whose elemental composition elements to be analyzed plus matrix is preliminarily given; (2) optimization of the analysis time regimes and the value of the maximum energy of the activating bremsstrahlung; (3) choice of a gamma-line of the isotope of an element to be analyzed by which the quantitative determination of this element is expedient. For these purposes a catalogue of nuclear-physical constants (half-lives and energies which was compiled from published data tables of gamma-line outputs obtained experimentally under standardized conditions for different values of the maximum energy of the bremsstrahlung as well as mathematical models of the monoenergetic gamma-ray spectra) has been used.     

Real-time analysis of CuO by inductively coupled plasma emission without external calibration

The study of a method, devoted to real-time detection of metallic pollutants present in stack gas, is investigated. This method is based on spectroanalysis using an inductively coupled plasma (ICP) emission system without external calibration. The fluidized bed technology is employed to inject metallic species into the ICP emission. The mass fluxes of copper oxide (CuO) are then determined by using the intensity ratios of the metallic element spectral lines with those of the plasma gas element (argon or dry air). These ratios and the plasma characteristics (atomic excitation temperature, degree of thermal disequilibrium θ=T_e/T_h) are inserted into a calculation code of plasma composition to determine the mass flux. The results are in good agreement using either argon plasma or dry air plasma. A study of the fluidized bed properties is made to compare our values with those resulting from the elutriation calculation of the copper oxide.     

Dechaos — A program for automatic or interactive analysis of gamma-ray spectra

DECHAOS is a gamma-ray spectral analysis program for personal computers. The program offers two modes of operation, automatic or interactive. The spectra to be analyzed can be acquired using any pulse height analyzer. The program includes routines for energy calibration, peak shape and efficiency calibration. Complex multiplets can be resolved automatically with the peak areas being determined using least-squares fitting techniques. Output tables include all data used in the calculation and peak information. The program is public domain software.