Waters 2998, Overview And Maintenance Manual

Page: 25 / 94

December 5, 2017, 715004753 Rev. B
Page 25
1.5.4 Reference wavelength compensation
A compensated reference wavelength collects wide-band absorbance data in a region of the
spectra where no known analytes exist. It is used to reduce detector drift and wander, which can
affect integration quality.
The detector calculates the compensation value by averaging the absorbance values within a
range of wavelengths that you select. It then subtracts that value from the absorbance value:
Abs-Comp(
t
) = Abs(
t
) - CRef(
t
)
where
Abs-Comp = absorbance-compensated
Abs = absorbance
CRef = compensation reference
t = elapsed time after start of injection
A starting and ending wavelength defines the compensation reference. CRef bandwidth must be

40 nm and

100 nm, and fall within a range of 190 to 800 nm.
Tip:
Select a compensation reference range where no analytes are expected to appear. Since
responses are subtracted from the absorbance value, any responses within the compensation
reference range can erroneously affect quantitative data.