Routine maintenance of HPLC

1. Reservoir filters sonication of bottle A (H2O with FA) once a month
2. In-line filter in the pump, sonication once a month
3. Water for LC-MS should be clean of residues (check supplier)



Sonication: 10% nitric acid followed by methanol and water (5 m in each)



Preventative measures:

1. Use wash vials after each set of tough samples:

• 1. 20% acetic acid in water (for salts)
• 2. 5% NH4OH (for salts)
• 3. IPA (for lypophilic compounds)
• 4. Acetone (for polymeric residues)
• 5. DMSO:H2O (for bio-residues)
• 6. 1 mM EDTA (for metallic residues or chelating agents such as catalysts).

2. Purge injector in the end of every sample set: Use an inlet method with purge injector in the shutdown method


Follow-up
1. Inject 100ul 50:50 MeCN:H2O after every tough sample to wash contamination
2. Inject blank (sample’s solvent) after every concentrated sample