Page 202 - Illustrated Pocket Dictionary of Chromatography

U

uncertainty The uncertainty in a result represents how much
error is associated with the result. The uncertainty is the total propa-
gated error introduced by each measurement or handling step that
occurs in the preparation and analysis of a sample. One way to
express this uncertainty is through the standard deviation, s. There-
fore, for the result x, the associated uncertainty is x ±s.

union, reducing Establishes a leak-free connection between
tubing of different outer diameters.

The union and fittings used to change from a 1/8≤ to a 1/4≤ copper tube is shown
here. The actual reducing union is shown at the bottom.

universal detector Capable of generating a signal for nearly
every analyte. The most common universal detector is a refractive
index detector. Only in the case where an analyte’s refractive index
perfectly matches that of the solvent will no signal be generated.

Illustrated Pocket Dictionary of Chromatography, by Paul C. Sadek.
ISBN 0-471-20021-2 Copyright © 2004 John Wiley & Sons, Inc.
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