PDA-100 Photodiode Array Detector
4-12
Doc. 031644-02 9/03
4.13 Poor Peak Shape
•
Concentration of standard is too high; column is overloaded
Dilute the standard.
Install a sample loop with a smaller volume.
•
Concentration of standard is too low
Increase the standard concentration.
•
Inappropriate mobile phase
Do not use a mobile phase that absorbs strongly at the peak absorbance
wavelength.
•
Incorrect sample wavelength selected
If little is known about the analytes in the sample, collect spectra over the full
wavelength range (using both lamps). For guidelines to follow when selecting
the sample wavelength, refer to Section 3.4.
•
Incorrect reference wavelength selected
Select a different reference wavelength. For guidelines to follow when
selecting the reference wavelength, refer to Section 3.4.
•
Sample bandwidth too wide
Select a bandwidth that provides the resolution required to achieve the desired
sensitivity. Narrow spectra peaks require narrow bandwidths. A wider
bandwidth reduces baseline noise, but may also reduce peak height.
•
Reference bandwidth too wide
Select a bandwidth that provides the resolution required to achieve the desired
sensitivity. A wider bandwidth reduces baseline noise, but may increase the
chance that the sample absorbs in the reference bandwidth, thus causing
reduced sensitivity and peak height.
