GC Analyzer – Complete Cycle Timeline

A process gas chromatograph operates in a fixed repeating sequence. Understanding the full cycle helps technicians diagnose timing errors, missing peaks, long cycle times, and unstable measurements.

End-to-End GC Sequence

This timeline shows the complete GC cycle from sample purge to ready state, including inject, separation, detection, and backflush.

Key Points for Technicians

• Purge stabilizes the sampling system and refreshes the loop.
• Inject timing defines peak size and repeatability.
• Separation occurs inside the column based on chemistry.
• Detection produces the chromatogram peaks.
• Backflush removes heavy components and protects the column.
• The analyzer then waits in READY state for the next cycle.

How This Helps in the Field

• Long cycle time → delayed or missing backflush
• Missing peaks → inject or valve timing issue
• Baseline drift → contamination or purge failure
• Unstable readings → pressure or flow instability