Troubleshooting — Shimadzu GC-2025
Quick Problem Identification
| Symptom | See Section |
|---|---|
| Baseline noise/drift/fluctuation | Section 1 |
| Poor peak shape (fronting/tailing) | Section 2 |
| No peaks or low sensitivity | Section 3 |
| Gas leaks or pressure problems | Section 4 |
| FID won’t ignite | Section 5 |
| Ghost peaks | Section 6 |
| Temperature won’t reach setpoint | Section 7 |
| Poor reproducibility | Section 8 |
1. Baseline Noise/Drift/Fluctuation
Symptoms
- FID baseline fluctuating
- High baseline noise
- Baseline detected as false peaks
📋 From manual
Causes & Solutions
Gas Leaks or Poor Gas Quality
- Check for leaks (septum, insert, connections)
- Use electronic leak detector
- Replace gas if purity low
- Wait 30–60 min for H₂ to purge air
Contamination
- Clean/replace glass insert
- Re-condition column — see Column Conditioning Procedure
- Clean/replace FID jet — see FID Component Replacement (Igniter & Jet)
- Regenerate molecular sieve filter — see Molecular Sieve Filter Regeneration
Environmental
- Stabilize room temperature
- Install air trap or use dry air cylinder
- Wait for H₂ purging
Software
- Increase Slope value (2× or 4×) to reduce sensitivity
📋 From manual
When to Call Service: FID collector white powder, damaged jet, cleaning fails
2. Poor Peak Shape
Fronting (Slow Rise)
Causes: Column overload, co-elution
Solutions:
- Dilute sample
- Decrease injection volume
- Increase split ratio — see Split_vs_Splitless_Injection
- Use thicker film column
- Change temp/flow
📋 From manual
Tailing (Slow Return)
Causes: Low injection temp, contamination, damaged insert, poor purge flow, septum fragments
Solutions:
- Increase injection port temp
- Re-condition column
- Verify/increase septum purge
- Replace glass insert — see Glass Insert & O-Ring Replacement (Detailed)
- Clip column inlet
📋 From manual
3. No Peaks / Low Sensitivity
Diagnostic Steps
- Check carrier gas flowing → Start flow, fix leaks
- Check FID ignited → Ignite (see Section 5)
- Check split ratio → Reduce ratio
- Check sample concentration → Increase concentration
- Check column temp → Verify appropriate
- Check detector “On” → Turn on
- Check zero level → Press MONIT → ZERO Adj
- Check signal cable → Reconnect
📋 From manual
When to Call Service: Damaged jet, damaged cable
4. Gas Leaks / Pressure Problems
Required Supply Pressures
- Carrier/Makeup: 300–980 kPa
- H₂/Air: 300–500 kPa
📋 From manual
Leak Detection Protocol
- Visual inspection (septum, insert nut, vents, connections)
- Electronic leak detector
- Pressure test (monitor over time)
For the software-based leak check procedure, see Optional: Software Leak Check.
Solutions
Gas Supply:
- Open cylinder valves
- Set correct supply pressures
- Replace cylinder if < 3 MPa
Hardware Leaks:
- Replace septum if damaged — see Septum Replacement (Detailed)
- Tighten insert nut or replace O-ring
- Replace compressed/damaged ferrules — see Graphite Ferrule Replacement (Detailed)
- Replace damaged gaskets
Calibration:
- Perform AFC offset calibration
📋 From manual
When to Call Service: Broken tubing, “valve leak error”, AFC/APC failure
5. FID Ignition Failure
Diagnostic Checklist
- Detector temp hot enough? → Wait for setpoint
- Column connected? → Connect column
- H₂ flowing? → Check supply, set 40 mL/min
- Air flowing? → Check supply, set 400 mL/min
- Igniter working? → Inspect filament, replace if broken — see FID Component Replacement (Igniter & Jet)
- Jet clean? → Clean with wire or replace
📋 From manual
Emergency Procedure
⚠️ If H₂ flowing and won’t ignite:
- Shut off H₂ IMMEDIATELY
- Ventilate area
- Do not retry until diagnosed
- H₂ accumulation = explosion risk
📋 From manual
When to Call Service: “H₂, AIR APC not ready” with no physical problem
6. Ghost Peaks
Causes & Solutions
| Cause | Solution |
|---|---|
| Septum bleed | Ensure septum purge flowing |
| Sample carryover | Bake column at max temp |
| Dirty syringe | Clean/replace syringe |
| Dirty insert | Replace glass insert + septum |
| Contaminated sample | Use fresh sample |
| Low gas purity | Replace carrier gas |
| Septum chips | Clip column inlet |
📋 From manual
7. Temperature Control Issues
Causes & Solutions
| Symptom | Cause | Solution |
|---|---|---|
| Won’t heat | Control not started | Press SYSTEM → Start GC |
| Won’t reach setpoint | Door open / insulation displaced | Close door, check insulation |
| Limited heating | Max temp limit too low | Increase max temp setting |
| Oven won’t heat | DET temp < COL temp | Set DET > COL (always!) |
📋 From manual
⚠️ Turn Off System & Call Service if these appear:
- “Temperature sensor error”
- “Overheat” error
- “Relay/heater control error”
8. Poor Reproducibility
Causes & Solutions
Flow Fluctuation:
- Replace cylinder if < 3 MPa
- Fix leaks
- Check/repair regulator
Column Overload:
- Decrease sample size
- Dilute sample
- Increase split ratio
Injection Problems:
- Clean/replace syringe
- Re-pack silica wool
Environment:
- Stabilize room temperature
📋 From manual
Sensitivity Restoration Checklist
□ Replace septum
□ Clean/replace glass insert
□ Replace O-ring
□ Check/replace ferrules
□ Re-condition column
□ Clean/replace FID jet
□ Replace FID collector if contaminated
□ Replace split/purge traps
□ Regenerate/replace molecular sieve
□ Verify carrier gas purity (99.999%)
□ Check for leaks
□ Verify all gas flows correct
□ Verify DET temp > COL temp
□ Run blank injection
See Maintenance for detailed procedures on each of these tasks.
When to Call Service
User-Serviceable:
- Consumables replacement
- Gas supply problems
- Basic cleaning
- Leak detection
Call Service For:
- Hardware failures
- Circuit board errors
- Sensor failures
- Persistent problems after troubleshooting
- “Hardware error” messages
- Internal component access
⚠️ Do not open side covers
📋 From manual
See Also
- Overview — Specifications
- Quick_Start_Guide — Operations
- Maintenance — Preventive maintenance
- References — Technical documents