Operating the detector 3-31
• Excitation (xλ or Ex) and Emission (eλ or Em) λ (nm) – Wavelength
setpoints for the two monochromators. The detector’s excitation range is
200 to 890 nm and emission range is 210 to 900 nm. You must set the
emission wavelength at least 10 nm above the excitation wavelength.
Tip: If any of these conditions are ignored, a detector error occurs, and
the sample set can be suspended.
• Bandwidth (nm) – Not an adjustable parameter on the detector, so the
value in this field is ignored. However, the static bandwidth of a detector
is 20 nm, so an entry of 18 nm in this field would document a value close
to the actual value in the method (for sample detail archival purposes in
Empower or Millennium32 software).
• Filter Type – Either a digital (Hamming) or RC filter. The digital filter
tends to yield peaks with far less distortion than does a standard RC
filter. The RC filter serves the need of those who want to follow
established measurement conventions.
• Filter Response – Time-constant setting of the filter (3, 5, 10, 20, and
40). The 474 detector interprets these numbers in terms of seconds.
However, values of this magnitude are too high for chromatography, so
the 2475 detector interprets these inputs at one tenth the specified
value.
Lamp Off Time (hrs) 1.0
Sampling Rate 2
Offset (mv) 0
Gain 1
Attenuation 64
Auto Zero Auto
Polarity +
Example of method parameters (Continued)
Parameter Value
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