Applications digital instruments

Note that digital instrumentation approximates the linear potential ramp as a staircase waveform [3, 6, 7]. There is a good agreement between the linear and staircase currents for ls/r = 0.25 — 0.30 for reversible processes (with ts being the time between the application of the potential pulse and the current sampling), if the potential step AE is less than 8 mV. 

Digital autoradiography (DAR) can be used in combination with TLC for the analysis of radiolabeled compounds, most frequently and " C. The method is simple and requires reasonably priced instrumentation therefore it is widely used for biochemical and pharmacological applications. The instrumentation for TLC-DAR can scan a 20 X 20 cm area, the radioactivity bands are visualized with a digital radiograph, and the digital data are processed with a high-capacity computer. 

Table 1. Distribution of applicability of cantilevers with different nominal stiffness towards various materials (cantilevers are manufactured by Park Scientific, Digital Instruments, and NT-DMT)...

KL Babcock, CB Prater. Application Note No. 11, Santa Barbara, CA Digital Instruments, 1995. 

Besides evident failures and easy-to-appreclate kinds of malfunctioning, analog instruments may present some performance degradations whose detection may imply application of sophisticated tests. The last point represents the peculiar difference in troubleshooting between analog and digital instruments. 

There are many industrial applications in which permanent records (extending over long periods of time) of the instrument readings are required. Chart recorders of various forms are available for this purpose. The most common general-purpose unit is the digital strip chart recorder, in which the input signal is used to drive the movement of a recording arm that passes over a paper chart in the y-direction. At the same time, the chart is... 

Electronic developments have revolutionized many types of laboratory equipment. Few instruments with dials are seen today, for instance. Digital readouts have taken over. While easier to use, estimating the amount of fluctuation of unstable signals is more difficult on a digital readout. There are also cases where an instrument s readout is more sensitive than its detection device, thereby causing unstable readings. For certain applications, a dial instrument may still be preferable. Electronic balances are now the rule rather than the exception. They are not only easy to use, but they generally require less service than mechanical ones. Prices have been considerably reduced in recent years. 

D. E. Smith, Application of On-Line Digital Computers in AC Polarography and Related Techniques, in J. S. Mattson, H. B. Mark and H. C. MacDonald (Editors), Computers in Chemistry and Instrumentation, Marcel Dekker, New York, 1972. 

One area of analytical chemistry which is currently developing rapidly is the automation of methods. Some degree of automation has been used for a number of years in instruments such as automatic burettes coupled to absorptiometric or electrometric end-point detectors, and in data output devices which provide continuous pen recording or signal integration facilities. The major features of recent developments include the scope for instrumental improvements provided by solid-state electronic circuits and the increasing application of digital computers (Chapter 13). 

Key instruments required for HPTLC analysis includes a sample application device, similar to the Automatic TLC Sampler 4, a digital... 

Fast Fourier transform instrumentation has been shown to be advantageous, both in the analytical and kinetic applications of voltammetry, for example, on Cd and Pb redox systems [43]. Active/passive transition for the Pb(Hg)/PbCl2 system has been studied using digital simulation [44]. 

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