on line mode will then require frequent sampling and rapid presentation of the sample to the instrument
followed by rapid analysis. It may be necessary to use a battery of analysers working in parallel to cope
with the number of samples presented. A particularly important example of 'batch' analysis is the use of
gas-liquid chromatography. The power of this technique to provide rapid analysis of complex mixtures
has led to its use for monitoring many organic processes, and its integration into many chemical plants.
Laboratory Robotics
The development of reliable robots together with sophisticated, programmable, computer controllers,
has begun to make an impact on laboratory practice in analytical laboratories. For example, where large
numbers of samples need to be routinely processed before measurement, a robot can provide for
sustained and prolonged operation. In so doing skilled operators can be released for other duties thus
achieving a saving in staff costs.
Robot design has developed along a number of lines. Cylindrical robots use a horizontal arm, which
moves up and down and swivels around a central column. Cartesian robots move and operate along the
axes of the familiar cartesian coordinates. Robot arm systems aim to parallel the innate flexibility of the
human hand and arm and have perhaps the greatest potential. The tools fitted to the robots for
manipulations can be changed at will and automatic changes may be built into the program of the
controller, thus automating the whole process. Figure 12.11 is illustrative of the use of a robot arm.
Figure 12.11
Robot arm system for sample preparation with different workstations
(reproduced by permission of Zymark Corporation).