WATERS CORPORATION 2424, Operator'S Manual, Page: 161 / 196

Selecting a solvent 6-3
Solvent quality
Use spectral-grade or HPLC-grade solvents to ensure reproducible results and
minimal instrument maintenance.
A dirty or impure solvent can cause these problems:
• Baseline noise and drift
• Plugged columns
• Blockages in the fluid path
Preparation checklist
The following solvent preparation guidelines help to ensure stable baselines
and good resolution:
• Filter solvents with a 0.45-µm filter.
• Degas and/or sparge the solvent.
• Protect solvents from shock and drafts.
Water
Use water only from a high-quality water purification system. If the water
system does not provide filtered water, filter it through a 0.45-µm membrane
filter before use. The total organic carbon reading should be as low as possible
(<5 ppb).
Buffer compatibility
The detector cannot be used with nonvolatile solvents such as salt-buffer
solutions. Volatile modifiers, such as acetic acid and ammonium formate, may
be used successfully.
Mobile phase modifiers that are suitable for mass spectrometry (for example,
ammonium acetate, ammonium bicarbonate, ammonium formate) can be used
for evaporative light scattering detection in concentrations of less than 0.01
M, or 0.1% (v/v %). Higher concentrations of nonvolatile materials in the
mobile phase cause greater baseline noise, lower sensitivity, and nebulizer
and small bore tubing blockages. High purity mobile phases with low boiling
points are recommended.
Caution:
Nonvolatile buffers are not recommended for use with the
detector. They cause noise and block fluid pathways.