Page 23 - Tandem Techniques

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elution features, and both GC and LC instruments incorporated sophisticated automatic samplers, and
computer data acquisition and processing systems. For the scientist involved with the development of
analytical instrumentation, these were the 'golden years' of analytical chemistry. In the late 1970s and to
the present time, a plethora of new analytical instruments were developed and manufactured, including
the various types of spectrometer, the X-ray crystallograph, electrophoretic and isotachophoretic
instruments and many others. Today the fully trained analyst has a wide range of techniques and
instruments to choose from, but to exploit them fully, a knowledge of electronics, engineering and
computer technology will be necessary. Above all, the modern analyst must have a sound understanding
of the basic principles behind the function of any instrument or technique that is employed. Perhaps the
complexity of modern analytical instrumentation, coupled with the necessary broad training of the
contemporary analyst, accounts for the long-overdue acceptance of analytical chemistry as an
established and important branch of chemistry.

Despite the speed and accuracy of the instrumental techniques that can now be employed, the use of
more than one, separately and in sequence, can still be a very time-consuming procedure. To increase
the speed of analysis, many of the techniques have been operated concurrently, so that two or more
analytical procedures can be carried out simultaneously. The tandem operation of two different
instruments greatly increases the efficiency of the analysis, but sometimes, due to unpredictable
interactions between one technique and the other, the combination can become difficult in practice.
These difficulties can become exacerbated if optimum performance is required from both instruments.

The purpose of this book is to describe the various techniques that can be combined in tandem form and
discuss the difficulties associated with their interfacing, together with the procedures that have been
developed to surmount them. Examples will be given that demonstrate the efficacy of the different
tandem systems that are described, and will include a range of different separation techniques as well as
different single and combined spectroscopic systems.