Consultation Hotline
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+1 (302) 618-8777
Mobile Phase Preparation: Prepare fresh eluent daily using 18.2 MΩ·cm deionized water. Degas eluent by helium sparging for 15 minutes or vacuum filtration through 0.22 μm membrane. Verify eluent pH/conductivity matches method requirements.
Pump Priming: Open purge valve and prime at 1-2 mL/min for 5 minutes to remove bubbles. Gradually increase flow to operating rate (typically 1.0 mL/min) over 2 minutes. Monitor pressure: stable pressure (±50 psi) indicates proper priming.
System Equilibration: Allow 30-45 minutes for column and suppressor equilibration. Monitor baseline conductivity until stable (<1% variation over 10 minutes). Check that background conductivity matches expected value for eluent composition.
Column Preservation: Flush analytical column with recommended storage solution (typically 10-20% organic solvent in water for polymer columns; manufacturer's solution for silica-based). Never store columns in pure water or buffer.
System Rinsing: Rinse entire flow path with 20-30 column volumes of deionized water to remove salts. For carbonate/bicarbonate eluents, use water rinse followed by 20% methanol/water solution to prevent microbial growth.
Pump Sealing: Leave pump seals in weak solvent (10-20% methanol) to prevent crystallization and seal damage. Engage pump seal wash function if equipped.
Normal Operation: Record baseline pressure daily. Sudden increase (>20%) indicates column frit blockage or guard column exhaustion.
Pressure Fluctuations: >±5% oscillation suggests bubble formation or check valve issues.
Troubleshooting Steps:
For high pressure: Replace guard column, backflush analytical column (if permitted)
For low pressure: Check for leaks, verify pump operation
For fluctuations: Degas mobile phase, replace pump seals
Acceptable Criteria: Baseline noise <1% of smallest peak of interest; drift <5% per hour
Baseline Artifacts:
Cyclic variations: Temperature fluctuations in lab
Random spikes: Electrical interference or bubble formation
Gradual rise: Column degradation or contamination buildup
Run system suitability standard at beginning and end of each batch
Calculate and document: Retention time RSD (<0.5%), peak area RSD (<2%), resolution (>1.5 between critical pair)
Verify calibration curve correlation coefficient (R² >0.995)
Check Valve Cleaning: Sonicate inlet/outlet check valves in 10% nitric acid for 20 minutes, rinse with DI water, then methanol
Seal Inspection: Check for crystallization at pump head. Replace seals every 3-6 months or 1000 hours
Piston Cleaning: Wipe piston with lint-free tissue moistened with methanol/water (1:1)
Autosampler Needle: Check for bending or clogging. Rinse with 0.5 mL each: DI water, 0.1M HNO₃, DI water, mobile phase
Injection Valve: Perform 20 injection cycles with 10% methanol to lubricate rotor seal
Loop Maintenance: Flush sample loop with 5 mL each: DI water, 0.1M HNO₃, DI water (reverse flush if possible)
Conductivity Cell: Clean with 0.1M HNO₃ for 5 minutes, rinse with DI water
Suppressor Device:
Chemical suppressors: Monitor backpressure, regenerate per manufacturer schedule
Electrolytic suppressors: Verify current settings, check for gas bubble formation
Temperature Stability: Verify detector and column oven temperatures with calibrated thermometer
Efficiency Test: Calculate plates/meter for early eluting peak (>20,000 plates/m for 4mm columns)
Asymmetry Factor: Measure at 10% peak height (0.8-1.5 acceptable)
Pressure-Flow Test: Plot pressure vs. flow (should be linear; deviations indicate wear)
Replace all inlet frits (pump, autosampler, inline filter)
Replace injection valve rotor seal if >10,000 injections
Replace all PEEK tubing sections in high-pressure zone (>6 months old)
Resolution Check: Verify resolution between fluoride and chloride (>2.0)
Theoretical Plates: Should not drop >20% from initial value
Blank Run Analysis: No peaks >3x baseline noise in method blank
Causes: Temperature fluctuations (±1°C causes ±1% RT change), eluent concentration variation, column degradation
Solutions: Use column oven, prepare eluent batches for week, monitor room temperature
Tailing Causes: Column degradation, secondary interactions, void formation
Fronting Causes: Overloading, incorrect eluent pH
Solutions: Replace guard column, adjust sample concentration, verify eluent pH
Causes: Contaminated eluent, exhausted suppressor, microbial growth
Solutions: Prepare fresh eluent, regenerate suppressor, add 1% methanol to eluent
Flush with 20 column volumes storage solution
Seal all reservoirs
Maintain column at 4°C if possible
Remove columns, cap ends, store at 4°C
Fill pump with storage solution
Document shutdown conditions
System Performance Log: Daily pressure, baseline, QC results
Maintenance Log: All services, part replacements, column installations
Column Life Log: Injection count, cleaning procedures, performance metrics
Document all calibration curves with statistics
Archive chromatograms demonstrating system suitability
Record all method deviations and corrective actions
Always wear PPE when handling concentrated acids/bases for eluent preparation
Never mix waste streams (organic vs. aqueous)
Label all solutions with preparation date and expiration
Use only grounded outlets
Check power cords monthly for damage
Keep fluid spills away from electrical components
Following this comprehensive maintenance protocol will ensure optimal IC performance, extended column life, and reliable analytical data. Regular maintenance typically reduces downtime by 40% and extends major component life by 60%. Always consult manufacturer's specific recommendations for your instrument model and column chemistry.