Instrument automation development

The computer has become an accepted part of our daily lives. Computer applications in applied polymer science now are focussing on modelling, simulation, robotics, and expert systems rather than on the traditional subject of laboratory instrument automation and data reduction. The availability of inexpensive computing power and of package software for many applications has allowed the scientist to develop sophisticated applications in many areas without the need for extensive program development. 

It is interesting to trace the development of instrument automation over the relatively brief period of the past ten to fifteen years. Early in this period, a truly automated instrument was a rare and expensive item built around a costly dedicated minicomputer. Automated data collection and analysis from any instrument which was not automated at the factory was usually accomplished by digitizing the data and storing it on a transportable media such as paper tape. These data were then delivered and fed to a timeshare system of some sort on which the data reduction program ran and which printed a report and sometimes a plot of the data. Often a considerable time delay occured between the generation and the analysis of the data. The scientist was at the mercy of the computer elite who could implement his data logger and provide the necessary computer resources to analyze his data. The process was expensive, both in time and in money. 

TA instruments has developed automated thermogravimetric analysis and related kinetic programs that enable a rapid determination of decomposition rates to be made. The following excerpt from a TA application brief [57] explains the method ... 

Liquid chromatography/mass spectrometry (LC/MS)-based techniques provide unique capabilities for pharmaceutical analysis. LC/MS methods are applicable to a wide range of compounds of pharmaceutical interest, and they feature powerful analytical figures of merit (sensitivity, selectivity, speed of analysis, and cost-effectiveness). These analytical features have continually improved, resulting in easier-to-use and more reliable instruments. These developments coincided with the pharmaceutical industry s focus on describing the collective properties of novel compounds in a rapid, precise, and quantitative way. As a result, the predominant pharmaceutical sample type shifted from nontrace/pure samples to trace mixtures (i.e., protein digests, natural products, automated synthesis, bile, plasma, urine). The results of these developments have been sig-... 

As described by Peccoud, automation of molecular biology spans at least three levels—automation of instruments, automation of experiments and automation of the laboratory (23). The same statement can be made about HTOS. Many of the systems in development today address only the automation of the instruments. Only a few companies are taking the next step to automate chemical experiments. The integration of all instruments used in the experiments with centralized data and control systems will form the basis for future automated HTOS laboratories. 

The capacity for lab automation that SFE brings to sample preparation is analogous to the analytical instrument automation that has been developing for the last twenty years. Such tools as automatic injectors and integrators for gas and liquid chromatographs are examples. The shift from manual technique towards instrument control helps to improve the robustness and repeatability of laboratory methods. 

Several types of automation and control systems have been used and all have performed successfully. Thus the WER-440 Is fully developed to be fitted with state-of-the-art Instrumentation, automation and control system technology covering several operating modes. This includes advanced control room layouts featuring process computers and colour CRT-dlsplays for monitoring and control duties. 

AUTOMATED MULTIPLE DEVELOPMENT (AMD). Linear, ascending, multiple developments are carried out in an automated instrument. The development distance is increased and the strength of the mobile phase is reduced (stepwise gradient elution) for each step. For silica gel, the mobile phase composition changes from more polar to less polar. AMD leads to zones with reduced diffusion and increased resolution because of a concentration effect. 

Important new instruments were developed after the UM chamber, aimed at increasing the efficiency of TLC through improvement of the separation mechanism. Programmed multiple-development TLC as elaborated by Perry (12) combines the techniques of continuous multiple development and evaporation. Recently this technique was improved by Burger (13). In this system the chomato-plate is developed several times in the same direction with various eluents of decreasing elution power. Between developments the chromatoplate is dried by vacuum. This method is termed automated multiple development (AMD) (14). High-performance TLC (HPTLC) is based on the use of chromatoplates coated with fine particles of narrow particle size distribution sorbent and is carried out with sophisticated instrumentation (15,16). 

The direct coupling of HPLC and HPTLC seems to be a very powerful method in the multiresidue analysis of pesticides. An instrument was developed for the direct connection of these chromatographic methods. The effluent obtained from a HPLC column was transferred directly to a TLC plate widi this device. According to the Camag AMD method, the plates were developed by a 20-step universal elution gradient from methanol-dichloromethane to n-hexane. The compounds investigated in this system were benomyl, 2,4-D, etrimfos, atrazine, phenylmercury acetate, and linuron. Densi-tometric evaluation was carried out with a computer-controlled Camag TLC scanner n, with HP 9816 S and TLC evaluation software 86. This method opens a new way in the automated multiresidue analysis of pesticides (134). 

As noted in previous editions, the trend in hydrocarbon analysis is away from manual test methods and increasingly favors automated instrumental methods. Commercial instruments are available that will perform many of the procedures described in this chapter. While ASTM committees have standardized tests based on some of these instruments, commercial development is rapid and new analytical instruments are... 

The biberty (Fig. 10), a monomode microwave reactor for automated SPPS, was recently introduced by the CEM Corporation [153]. Although this instrument was originally developed for SPPS, it also allows for a broader scale of solid-phase applications. The solid-phase vial is equipped with a polypropylene frit and cap at one end (the entire assembly fitting into the standard 10 mb CEM reaction vessel) to allow the processing of 0.1 to 1.0 mmol quantities of resin attached substrates. An integrated fiber optic probe provides... 

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