摘要:

An instrument which uses two computers operating in parallel for waveform generation, data acquisition, and general control of an electrochemical potentiostat is described. It is presently programmed to perform eight different pulse methods, but other methods can be tried and then included in the program, if desired. Liquid or solid electrodes, either dropping or stationary, may be used. Step times down to 31 μs (sweep rates in excess of 100 V/s) are available with total timing errors of less than 20 ns. Exact control of step time, time between step application and current integration, length of integration, and delay between drop fall and experiment beginning is provided. Different values of the above parameters, except for drop fall delay, may be selected for the anodic and cathodic steps in differential methods, allowing unsymmetrical operation. Circuits to provide drop profile data in tast polarography and to record drop times for surface tension measurements are included.

ISSN:1073-9149    

DOI:10.1080/10739148608543602

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

A low cost, high precision electronic integrator allowing accurate integration of analog input signals over a wide dynamic signal range for long and short integration periods is described. The utility of this integrator is demonstrated in the controlled potential reduction of Pb++where the i - t curve is represented by the number of coulombs accumulated and displayed in digital form. With this value and application of Faraday's Law, the n value of the electrode reaction is calculated. The obtained n value of 1.95 shows good agreement with the expected value of 2.00.

ISSN:1073-9149    

DOI:10.1080/10739148608543603

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Optical fibers, analytical chemistry, and fluorescence spectroscopy have been integrated to form the new technology of remote fiber fluorimetry. Among the many potential applications of this technology is the measurement of volatile organochlorides in ground water and in the vadose zone. The key to this application was the development of a fiber optic chemical sensor (FOCS) with sub-ppm sensitivity for, at least, chloroform and trichlorethylene (TCE). We present here the concept and instrumentation of remote fiber fluorimetry, the design and laboratory evaluation of an organochloride FOCS, and preliminary field results of the application of the FOCS to contaminated well water.

ISSN:1073-9149    

DOI:10.1080/10739148608543604

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

An original rotor for Sedimentation Field-Flow Fractionation (SFFF) has been designed, constructed and verified in practical operation. A convenient design of its rotary passage permitted the extrachannel zone spreading to be reduced to a level comparable with the experimental errors of the determination of the zone width (ca. 1 % relative). The high reproducibility of SFFF separations and the reliability of the apparatus for SFFF was proved during a long period operation.

ISSN:1073-9149    

DOI:10.1080/10739148608543605

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

An automatic system for measuring electroluminescence spectra is described. The instrument works in photon counting mode to record low-intensity light. Wavelength separation is done by a rotating interference filter. The instrument is controlled by a microprocessor, and is capable of generating arbitrary pulse wave-forms for the excitation of electroluminescence. The temporal variation of the spectra can be recorded at millisecond timescale. Application to electrogenerated chemiluminescence of luminol and fluorescein is shown.

ISSN:1073-9149    

DOI:10.1080/10739148608543606

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:1073-9149    

DOI:10.1080/10739148608543607

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:1073-9149    

DOI:10.1080/10739148608543608

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:1073-9149    

DOI:10.1080/10739148608543609

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor