Page 64 - Tandem Techniques

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Chapter 2
Identification Techniques for Tandem Use

Introduction to Identification Techniques

This chapter will give a brief introduction to the different spectroscopic techniques that have been used
in tandem systems. The intent is to provide those completely unfamiliar with spectroscopy, sufficient
understanding to help them operate tandem systems and perhaps identify eluted components by spectra
matching. The information given here is quite inadequate to permit structure elucidation of an unknown
substance from spectroscopic data, which would require the services of an experienced spectroscopist.

Most of the identification methods employed in tandem systems are spectroscopic in nature. The word,
spectrum, was originally given to the colored bands formed by passing visible light through a prism and
the study of these colored bands was given the term spectroscopy. The study of visible light was, in due
course, extended to shorter wavelength and higher frequencies and thus, as the shortest wavelength of
visible light is violet, the term ultra violet spectroscopy was introduced. At the other end of the visible
spectrum (red), light of longer wavelength and lower frequencies are to be found and this range was
termed the infrared region. Below the ultraviolet region are the X-rays and at even shorter wavelengths
and higher frequencies are the y-rays. Beyond the infrared region is the far infrared and microwave
region, followed by the range of frequencies used for radio and television transmission. Intermediate in
the