Thermo Scientific 074114, Operator'S Manual

Page: 51 / 148

3 • Operation and Maintenance
Doc. 065378-01 1/12
43
3.4 Optimizing Detector Performance
The performance of the Dionex PDA can be optimized by careful selection of key
operating parameters. This section defines these parameters, describes how they
interact, and offers guidelines for selecting them. The table below summarizes the
topics discussed in this section.
Flow Cell Material
The flow cell material must be chemically compatible with the mobile phases and
analytes of interest.
Operating Parameter Performance Characteristics Affected
Flow cell material Chemical compatibility
Rise time Peak resolution, sensitivity, baseline noise
Data collection rate Peak resolution, disk space
Sample wavelength Sensitivity, linearity
Bandwidth Sensitivity vs. baseline noise
Reference wavelength Baseline drift
Reference bandwidth Baseline noise, baseline drift
Bunch width Spectral resolution, peak match, disk space
Step* Baseline noise, rise time, data collection rate, disk space
Average* Rise time, data collection rate
Negative absorbance Peak detection, baseline noise, linearity
*
Set automatically by Chromeleon 6.8; not available in Chromeleon 7
Strong bases can etch the fused silica windows of the flow cell. If the
mobile phase is a base, make sure the mobile phase concentration
does not exceed 0.1 M. If the concentration of the base is greater than
50 mM, disconnect the separator column and flush the system with
deionized water for 5 minutes at 1.0 mL/min immediately after the
analysis. If strong base remains in the cell for 1 to 2 days, the cell
windows may need to be replaced.
Do not use a PEEK flow cell with normal phase or chlorinated
solvents; these solvents will damage the cell.