Automated instruments examples

The use of "fixed" automation, automation designed to perform a specific task, is already widespread ia the analytical laboratory as exemplified by autosamplers and microprocessors for sample processiag and instmment control (see also Automated instrumentation) (1). The laboratory robot origiaated ia devices coastmcted to perform specific and generally repetitive mechanical tasks ia the laboratory. Examples of automatioa employing robotics iaclude automatic titrators, sample preparatioa devices, and autoanalyzers. These devices have a place within the quality control (qv) laboratory, because they can be optimized for a specific repetitive task. AppHcation of fixed automation within the analytical research function, however, is limited. These devices can only perform the specific tasks for which they were designed (2). 

There are four stages in an automated instrument analysis. In the first stage, the instrument operator initiates the experiment by means of dialog programs on the minicomputer. Examples of the dialogs for the HPGPC operation are shown in Figures 1-4. 

Some companies (75, 76) have developed their own automated instruments for combinatorial library synthesis in solution to produce large, purified arrays of discretes (up to several tens of thousands of individuals) the available information is obviously scarce, but an example of such a proprietary integrated synthesizer will be presented in section 8.2.6. 

Fully automated instruments with low-medium throughput, typically a few hundred compounds per week for one- to three-step synthetic schemes in solutions, are suitable for small, focused libraries where more challenging reaction conditions such as heating, using reactive intermediates, or when inert atmospheres are needed. These instmments are also suitable for intermediate steps in the construction of larger libraries. For example, monomer rehearsal can be performed by reacting a common intermediate with various monomer candidates, and a small model library may be prepared. Even chemistry assessment may be tackled with these instmments. 

The development of modern microcomputers and associated instrumentation enables the automatical of a nunber of IGC techniques. Automation is desirable because often 50 to 100 separate injections of very small volumes of probes are required over a period of time as the temperature of the GC is slowly increased, for example in the determination of transition temperatures or crystallinity. This paper will discuss the determinations of polymer crystallinity and the surface area of polymer-coated particles using automated instrumentation. 

Homogeneous enzyme immunoassays have also been developed for serum T4 determination. These procedures are rapid and simple to use and have also been applied to several major automated instruments.For example, the enzyme-multiplied immunoassay technique (EMIT) for T4 measurement uses glucose-6-phosphate dehydrogenase covalently hnked to T4 as the enzyme label.Binding of T4 specific antibody to this label reduces enzyme activity, perhaps as a result of steric or allosteric inhibition As the concentration of unlabeled T4 increases, less enzyme-labeled hormone is bound by the antibody. As a result, the catalytic activity of the unbound enzyme conjugate increases in direct proportion to the amount of T4 in the specimen. The indicator reaction involves oxidation of glucose-6-phosphate with simultaneous reduction of nicotinamide-adenine dinu-... 

Automatic and automated instruments can be differentiated as follows automatic instruments tend to perform specific operations at given points in a process or analysis to save time or effort, e.g. robotics, while automated instruments tend to control some part of a process without human intervention and do this by means of a feedback mechanism from sensors. For example, an automatic conductivity detector might continuously monitor the conductivity of a process stream, generating some alarm if the conductivity goes outside a preset limit. An automated detection system could transmit the measured conductivity values to a control unit that, by utilising a feedback mechanism, adjusts relevant process parameters, e.g. temperature or cycle time, to maintain the conductivity of the stream within the preset limits. 

The dynamic (working) range of an automatic or automated instrumental technique must obviously fit the working range of concentrations to which it is being applied. In a continuous or automatic titration, for example, the dynamic range and span are governed by the sample size (the volume of the sample and the concentration of desired species in it), the size of the buret, and the concentration of the titrant. The presence of a second titratable species (interference) in the system reduces the usable span by the amount of the second species, since the titration will measure both species. 

Chromatography is perhaps one of the most widely applied automated instruments in process analysis, particularly in the nonaqueous chemical and petrochemical industries [8]. In petroleum refining, for example, the crude petroleum, containing hundreds of chemicals from methane to asphalt, is converted to salable cuts by distillation. Further processing by catalytic reforming, distillation, and chemical reaction yields materials used for fuels, lubricants, petrochemical feedstock, and other applications. 

The glass electrode used for measuring pH is one of the most successful examples of potentiometry in automated instruments. Modern glass electrodes are highly reliable they give selective, sensitive, and stable response to acidity over a very wide range of pH and have been widely applied in industrial monitoring and control. 

A further useful feature is the automatic control and sequencing of multiple functions of the instrument by the built-in electronics, which are effectively a dedicated microcomputer. In some cases a closed loop is involved, so that certain functions are truly automated. For example, an instrument involved in enzyme determinations will monitor the temperature of the reaction cuvette and correct the assayed activity for deviations from the nominal temperature. Also, after initial calibration, an instrument may compare subsequent standards or control samples with the initial value and automatically correct for calibration drift, as well as alerting the operator to excessive drift. 

The empirical data for this study is based on two separate research projects and is comprised of participating observations and semi-structured interviews. In the research project completed in 2007, personnel in all functions associated with the asset were interviewed, both onshore and onshore managers, offshore operators within all disciplines on the platform (electro, mechanic, automation, instrument, process, etc.), and onshore discipline experts within the same disciplines. Sixty-nine interviews (including all three shift rotations offshore) were carried out. Fimctions were covered until saturation (Strauss Corbin 1990). Examples of participating observations include being present at different meetings in the collaboration rooms both onshore and offshore, as well as following the maintenance work of the operators in the process plant. 

Indeed, P NMR is widely used in a quantitative fashion. Computer-controlled and automated instruments, used in combination with robotic sample changers, make the large number of analytical samples much more manageable. With customized software, the spectrometer can automatically accumulate and store data, perform the Fourier transform and integration, calculate the relative distribution of species present and generate the analytical report. As an example, Figure 5 shows the output from a routine oligophosphate assay. 

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