Waters ACQUITY UPLC M-Class - D.2 Solvent recommendations; D.2.4 Operation with neutral or basic mobile phases

• Methanol
• Methanol/water mixtures
• Water
D.2.2 Solvents to avoid
Do not use these solvents:
• Solvents that contain halogens: chlorine, fluorine, bromine, or iodine.
Note: To prevent significant damage to the mass spectrometer, when using strong acids as
cleaning agents, ensure that the system is disconnected from the flow path.
• Strong acids, unless using them as cleaning agents. Avoid using acids as mobile phases
when their pH is less than 2.0.
• Solutions that contain strong concentrations (greater than 0.1% wt.) of complexing agents like
ethylenediaminetetraacetic acid (EDTA).
• Compounds that form peroxides, such as UV-grade ethers, dioxane, and diisopropylether.
D.2.3
Recommended cleaning agents
You may use these cleaning agents:
• Formic acid (≤10%)
• Phosphoric acid (≤30%)
• Sodium hydroxide (≤1M)
D.2.4
Operation with neutral or basic mobile phases
You can operate the system with an acidic or basic mobile phase, within the range of pH 2 to pH
10, if you follow the recommendations listed in this section.
Recommendation: To avoid damaging capillary tubes, never use mobile phases exceeding pH
10.
Note: Adding organic solvent reduces contamination. Waters recommends that you pre-filter the
mobile phase.
• Use clean water and glassware.
• Add up to 20% of an organic solvent; use acetonitrile or methanol when possible.
• Filter the mobile phase with 0.1 μm or smaller PVDF filters.
• Prepare new mobile phase every two days.
• Clean the system.
November 26, 2019, 715003588 Revision C
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