Extinction coefficients are named according to the unit of
concentration contained within them. For example, a molar extinction
coefficient is the absorbance of a 1M solution of the compound at a
specified wavelength (usually the lamda maximum) in a 1 cm cell.
Extinction coefficients can be determined by plotting as standard
curve of the compund at a given wavelnegth, and then finding the slope
of the line. This value is very important in determining the
concentration of the compound yu are measuring, according to the
Beer-Lambert law A = e l c, where A is absorbance, e is the extinction
coefficient, l is the path length, and c is the concentration.
Hope this helps.
Jay Mone'
