Compound Selective Detectors

This category refers to detectors that respond specifically to whole molecules or, more commonly, to various functional groups in a molecule.

An example of a detector responding to functional groups is the automatic titrimeter described by James and Martin in their earliest publications on the separation of the lower fatty acids. Although slow and lacking in sensitivity by modern standards, this detector represented a major advance at the time. Attempts over the years to use microcoulometers as detectors for compounds capable of oxidation or reduction at suitable electrodes have virtually disappeared since, in general, they have slow response and the electrodes are subject of contamination.

Compared to element-selective detectors, there are very few compound-selective detectors and indeed in terms or modern commercially available equipment they can be limited to four - the electron-capture detector (ECD), the photoionization detector (PID) and two spectroscopic detectors, Fourier transform infrared (FTIR) and ultraviolet (UV) detectors. Trapping out polynuclear aromatic hydrocarbon fractions for further analysis by UV spectroscopy was reported many years ago but although there is now an online GC-UV instrument on the market, it is of limited application and will not be discussed further.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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