Doc. 031644-02 9/03
3-1
3 • Operation and Maintenance
3.1
Operating Guidelines
NOTE The PDA-100 Photodiode Array Detector is designed for
use with IC (ion chromatography), BioLC, and HPLC
(high-performance liquid chromatography) systems and
should not be used for any other purpose. If there is a
question regarding appropriate usage, contact Dionex.
In the U.S., call 1-800-346-6390 and select the Technical
Support option. Outside the U.S., call the nearest Dionex
office.
3.1.1
Mobile Phases
Solvent quality significantly affects detection limits and instrument
performance. To ensure optimal performance of the PDA-100, follow the
precautions below.
•
Prepare all mobile phases with spectroscopy-grade solvents, reagent-
grade chemicals, and ASTM Type I (or better) filtered, deionized
water.
•
Degas all mobile phases before use and maintain them in a degassed
state.
•
Mobile phase pH affects not only the retention time of the separation,
but the sample absorbance and the background absorbance of the
mobile phase. If an analysis employs chemical suppression and
compound detection techniques, compare the UV cutoff of the mobile
phase before and after the suppressor to see whether it is
advantageous to locate the PDA-100 ahead of the suppressor. This
location also limits suppressor exposure to backpressure.
Strong bases can etch the 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.