Thermo Scientific Dionex UltiMate 3000 Series Operating Instructions Manual page 84

UltiMate 3000 Series:
VWD-3100 and VWD-3400RS Variable Wavelength Detectors
5.5.1.2 Mobile Phases
Mobile phase quality significantly affects detection limits and instrument performance. To
ensure optimal performance of the detector, observe the following guidelines:
• Prepare all mobile phases with HPLC-grade solvents, reagent-grade chemicals, and filter
HPLC-grade water.
• Degas all mobile phases before use and maintain them in a degassed state.
• 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 separation column and flush the system
with HPLC-grade water for 5 minutes at 1 mL/min immediately after the analysis.
• Mobile phase pH affects not only the retention time of the separation, but the sample
absorbance and the background absorbance of the mobile phase.
• When changing from a buffer to a different operating mobile phase, be sure the solvents
are miscible and will not induce precipitation of the buffers. Flush the cell with a buffer-
compatible solvent (in most cases, HPLC-grade water) immediately after the analysis. Do
not allow buffers to remain in the cell for extended periods.
For information about the properties of common used mobile phases, see section 10.1 in
Table 1 (→ page 145).
Page 76 Operating Instructions