Data processing for atomic absorption spectrometry with a microcomputer

A general-purpose microcomputer has been designed and built to provide a data acquisition and control system. The microcomputer can be interfaced to an atomic absorption spectrometer to provide reliable and economic processing of data. The system provides scope for expansion in order to control various instrumental operating parameters simultaneously or consecutively.     

毛细管电泳微机化扫描伏安检测器

描述了一种毛细管电泳微机化扫描伏安检测器,用微机通过D/A和A/D转换器控制扫描电压和采集电流信号,用12bit的D/A转换器和12bit的A/D转换器通过伏安仪分别与Ag/AgCl参比电极和工作电极相连,进行电位控制和数据采集.讨论了扫描电位的产生和数据采集的控制方法,并用本系统分离测定了对苯二酚和儿茶酚,结果令人满意.     

Voltammetric instrumentation controlled by two microcomputers

A voltammetric instrument with two microcomputers is described. An INTEL SYS 80/10A microcomputer, interfaced to the electrochemical cell, is provided with general machine-code routines in PROM for control and measurement. A personal computer (Luxor/Scandia Metric ABC 80) is used for control of the microcomputer and for evaluation of results. A list of machine-code routine addresses with parameters comprises a program. The parameters are selected at the personal computer which also loads the program into the SYS 80/10A and initiates the experiment. The use of two low-cost computers eliminates the need for a complex multi-task system or a remote host computer.     

2-D reconstruction of elemental distribution within a sample using neutron capture prompt gamma-rays

The technique of emission tomography employing neutron capture prompt gamma-rays is described. Experiments have been carried out to demonstrate this technique employing a high flux reactor neutron beam using an HPGe detector and a scanning system which incorporates a BBC microcomputer for control, data acquisition, image reconstruction and display. Neutron tomography of the same object was also performed in order to correct the emission tomography results for the neutron flux depression within the sample. The images produced represent the intensity of the induced gamma-ray of interest, and hence the concentration of the isotope of interest.     

Oxygen electrode-based enzyme immunoassay for the amperometric determination of hepatitis B surface antigen

Specific antibodies labelled with glucose oxidase are immobilized onto a gelatin membrane, which is fixed over an oxygen electrode. The sensor is immersed in a standard glucose solution and a signal is obtained by measuring the consumption of oxygen by the enzyme catalyzed reaction. The response increases linearly with increasing antigen concentration over the range 0.1–100 μg 1^?1. A microcomputer is used for data acquisition and processing.     

Development of an Automatic Electrochemical System for Differential Pulse Amperometry and Its Application for Se(IV) Determination

This work presents the development of an automatic system for differential pulse amperometry (DPA) with electrochemical deposition. The system consists of a microcomputer, running a home‐made software, connected to a commercial potentiostat through a data acquisition board. The system was applied for selenium determination using gold electrode and flow injection analysis (FIA). Analytical curves were obtained in the concentration range of 20 to 400 μg L^?1 for Se(IV), with a calculated detection limit of 6 μg L^?1. The analysis results for fish samples doped with Se(IV) and digested in a microwave oven showed recoveries above 93%.     

STM数据采集分析计算机系统

扫描隧道显微镜(STM)是1982年问世的研究物质表面结构的新型仪器,近几年来得到了很大的发展。与其它各种类型的显微镜相比,它的最大优点是具有较高的分辨率(平行和垂直于样品表面方向的分辨率分别可达1和0.1),共弱点是数据的处理和显示功能不强。发展STM的自动控制、数据采集、实时显示和数据分析的计算机系统,对于改进仪器的性能至关重要。本文介绍我们研制的一套STM数据采集、存储、实时显示和数据分析系统,并以用该系统采集的高取向石墨数据为例,介绍系统的软件功能。     

Scanning electrochemical microscopy-development of instrumentation utilizing piezo-bimorph X-Y scanners

The development of the instrumentation of a scanning electrochemical microscopy (SECM) is presented. The core of the SECM sensing system is constructed based on piezobimorph scanners, a mechanical micropositioner of multi-dimensional adjustment and ultramicroelectrodes. The control of the electrochemical cell and the SECM system is realized by a battery powered bipoteniostat and analog control circuits respectively with the control of a microcomputer work station. The demonstrations of SECM experiments are given on both a standard IDA sample and a silver electrode. Discussions on the resolution and quality of SECM image are made.     

Electrochemical heat flow calorimeter

A device designed for research of heat phenomena occurring in chemical power sources (CPS) is described. The device includes two functional blocks: electrochemical and calorimetrical, operating under single control, which allows simultaneously performing electrochemical and calorimetric measurements. The calorimetric block is a heat flow calorimeter. The calorimetric chamber design provides the possibility of studying thermal processes in laboratory electrochemical cells and CPS of planar, disk, and prismatic design. The absolute measurement error of the heat flow is ±50 μW at the resolution of 1 μW. The operating temperature range of the calorimetric chamber is 0–90°C. The basis of the electrochemical block is a module of a four–range potentiostat–galvanostat. The maximum polarizing current of the potentiostat is ±200 mA at the maximum voltage on the auxiliary electrode of ±10 V. Multiuser remote access from the user computers over Ethernet to the device is provided for control and treatment of experimental data. Digital deconvolution filters allowing to compensate the response rate of the heat flow meter are used for processing primary data of calorimetric measurements.     

The use of a micro-mini-mainframe computer network in the analytical chemical laboratory

A network of communicating and cooperating computers, consisting of a central host computer and one microcomputer per experiment, is described. The network is intended to be used as a universally applicable tool in analytical chemical research. A specially developed programming language, easy to learn, offers the possibilities of real-time clock-controlled data acquisition, control of experiments, simple logical decisions, and cooperation with the host computer, which simultaneously runs a program in a conventional higher language such as FORTRAN. The analytical application used for illustration relates to inductively-coupled plasma emission spectrometry.     

Torsion pendulum automation by a single microcomputer

A new automated torsional pendulum is described. It uses a single photocell for the measurement of the period of oscillation and the logarithmic decrement. Data acquisition, data processing and temperature control are all performed by a single microcomputer. The result is that the instrument can be produced and operated more cheaply than before.The principles behind the design, the method of determining the shape factor, the calibration procedure and the software are discussed. Examples are given to illustrate the use of this instrument. A practical limitation is that the loss tangent should not exceed about 3.     

Computer system for a small analytical research laboratory

A solution to three problems concerning computer use in our laboratory is described. The problems are: replacement of obsolete computer equipment, consolidation of data processing programs, and unification of the format of kinetic data from different sources. The solution involves use of a central super microcomputer with personal computers used primarily for data acquisition and temporary storage.     

Biochemical data-processing with microcomputers : Part 3. On-line data acquisition from a continuous flow analyzer

A program, written in BASIC, is described which allows data acquisition from a continuous flow analyzer. The program was developed for a readily available microcomputer, but should be easily modified for use on similar machines. Once the peak height has been measured, the concentration of the analyte is calculated by reference to a previously defined calibration. The program is designed to handle data from more than one channel, although there is a practical limit of 3–4 simultaneously active channels. The results of the separate assays are collated and printed as a group for each specimen, even when the analytical methods require different times for completion.     

Computer Assisted Data Acquisition and Analysis for Size Exclusion Chromatography

Abstract

Two programs, ACEACQ and ACEANN, provide data acquisition and analysis for Size Exclusion Chromatography (SEC). ACEACQ is used for data logging, real-time smoothing and data reduction by boxcar averaging. ACEACQ requires that traditional SEC hardware be coupled with a Hewlett Packard data logger and microcomputer. A Mettler electronic balance is connected to the computer in a novel fashion to continuously monitor the mass of solvent eluted during an experiment. ACEANN provides analysis for the data collected by ACEACQ. Calculations include molecular weight averages, molecular hydrodynamic diameter averages and column separation efficiency parameters. Significant reductions in analysis time have been realized along with improvements in accuracy of data acquisition, analysis and experimental reproducibility.     

Kinetic determination of magnesium and calcium by stopped-flow injection analysis

A kinetic method for the simultaneous determination of magnesium and calcium ions in solution is described. The method is based on the dissociation reactions of cryptand (2.2.2) complexes; a stopped-flow injection technique is used with spectrophotometric monitoring of the phthalein complexone complexes of the released metal ions. Analyses were done at a rate of 80 h^?1, with injected sample volumes of 80 μl. A microcomputer system for data acquisition and control of the system is described.     

A versatile computerized system for the development and comparison of electroanalytical procedures

The computerized system reported is suitable for potentiometric and voltammetric techniques. All instrumental settings are fully automated and new analytical schemes can be implemented simply by software modifications. A dedicated 4K, 16-bit microcomputer allows rapid real-time data acquisition and processing. By application of a data acquisition scheme simulating a multichannel analyser, stripping potentiograms and chronopotentiograms can be conveniently represented in digital form as time vs. potential relationships. Procedures developed on the system can be transferred to microprocessorcontrolled equipment as the software for complete analytical procedures, including device handlers, data storage buffers and graphic output, occupies 3–4K words. Flexibility in program editing and assembling is obtained with an optional data link to a medium-sized, time-shared computer with extensive software packages. The link described is of simple construction and can be readily established between computers with standard teletype terminals. The performance of the system is illustrated by comparing the selectivities of two established voltammetric stripping techniques with the selectivity of a new potentiometric technique developed on the system.     

Software package for quantitative analysis of solid materials by energy-dispersive x-ray fluorescence spectrometry without absolute calibration

A software package for quantifying elements in solids from energy-dispersive x-ray fluorescence data is described. The algorithm is based on the fundamental parameter approach and facilitates the simultaneous determination of several elements at widely varying concentrations. The software comprises three programs. One program, for spectrometer control and data acquisition, resides in a dedicated microcomputer. The two other programs, for spectra deconvulution and data evaluation, reside in a larger central computer. On-line communication between the computers is feasible, and the system facilitates the implementation of new improved programs. The performance of the system was tested on standard reference materials, and satisfactory accuracy was obtained for up to 21 elements.     

Rapid automatic potentiometric method for analytical control in the manufacture of extraction phosphoric acid

A rapid automatic method for determination of free sulphuric acid in the manufacture of extraction phosphoric acid from apatite has been developed. It is based on potentiometric titration combined with the Gran approach for linearization of the titration curve. The analysis is done with an automatic potentiometric titrator controlled by an HP-85 microcomputer. BASIC software activates the system to perform the data acquisition and calculations, and the whole operation takes only 7-8 min.     

Adapting a thermobalance to constrained rate thermogravimetry

A thermobalance has been converted to allow interactive control of the heating rate from the rate of mass loss of the sample (Constrained Rate Thermogravimetry). The interfacing of the balance and temperature controller both to an ACORN RISC microcomputer and to a PC microcomputer is described along with an outline of the software required. This provides an economic route for the conversion of existing thermobalances. Problems of achieving effective control and acceptable data recording are outlined. The nature of the TG curves obtained from interactive temperature control and the influence of control parameters is discussed.