Principles of automatic analysis

Chapter 1 discussed the reasons for automation and attempted to set out the needs of analysis. This second chapter defines the objectives of automatic analysis and describes how, in principle, these can he achieved. 

Analytical procedure is a systems problem and the samphng, pretreatment, measurement, data collection and reduction, and final reporting all have to be considered in a fiilly automatic approach. Computerization is often considered to he synonymous with automation but, although microprocessor technology is certainly changing the face of automatic instrumentation and influences both the control aspects and the data reduction, computerization is only a part of automation. Computers should simply be considered as tools of the trade within the area of automation. 

Automation has been applied for a number of years in process control instrumentation, but the major impetus to introduce automatic devices into laboratories stems from three sources (1) the introduction of the continuous-flow principles as outlined by Skeggs [1] (2) the general demand for clinical chemical measurements, which represents a ready and sizeable market for instrument companies, and, more importantly, (3) the abihty to handle large volumes of data and package them in a form suitable for presentation to analysts and customers, through the use of mini- and micro computer systems hnked to a control computer. 

The availabihty, at a reasonable price, of computer power, along with the various associated peripherals that are imperative for a viable computer system, is seen as being the most important influence on future growth in this area. Recent years have seen the dechne of the mainframe due to the increased power and availabihty of the personal computer. Today s Pentium-based IBM-compatible PCs with 100 MHz internal clocks and SOO megabyte hard disks are a far cry from those that were popular with chemists a decade ago. 

This needs to be balanced against the ever-increasing cost of rehable and effective software that is also required to maximize the usefulness of computer hardware. Recent years have seen the increased popularity of the Microsoft Windows operating system. MS Windows is an attempt to give PCs the window management environment of professional 

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We discuss in this chapter analysers that arc highly automated, such as flow injection and discrete analyzers. In addition, laboratory robotic systems that are becoming more and more commonplace for sample handling and preparation arc also described. The latest advances in automation involve the development of microlluidic systems, which are sometimes called lab-on-a-chip or micro total analysis systems. These recent developnienis are also described here. It is important to note that the same principles of automatic analysis discussed here also apply to process control systems, which analyze the current state of a process and then use feedback to alter experimental variables in such a way that the current state and the desired state are nearly identical,... 

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