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derivative. Such spectra, used in conjunction with a mass spectrum, would also be very useful for
elucidating the structure of a completely unknown substance. The spectra obtained by solid deposition
on an IR transparent surface can differ significantly from those obtained by other sampling methods,
e.g. by using Nujol mulls or potassium bromide pellets. The difference will be more apparent with
certain types of compounds. For example, a sugar solid, formed by the rapid evaporation of water from
solution, will tend to form a visibly clear 'glass'. Scattering and fine structure artifacts in spectra
observed in solid preparations will be absent in such samples.
Figure 8.18
Spectra of Dextrose Taken by Three
Different Sampling Methods.
Courtesy of Lab Connections Inc.
