How should I set the Headspace GC cycle time using ICF 3.0 and higher with Empower? - WKB63637

ENVIRONMENT

• Agilent HS7697A Headspace Sampler
• Agilent G1888 Headspace Sampler
• Agilent ICF 3.0 and higher
• Empower Personal
• Empower Workgroup
• Empower Enterprise
• Agilent Instrument Control Framework
• Agilent 7890 GC
• Agilent 6890 GC

ANSWER

The best way to determine the GC cycle time is to make a few blank (no injection or solvent) GC runs using the GC method. Either enable the Track GC cycle time preference parameter or manually count the time from the start run command until the complete system becomes ready for the next run. Use a GC cycle time slightly longer than the measured average cycle time.

With GC-Headspace communications and "Follow 7890" enabled, the entry cannot be shorter than the known GC run time.

ADDITIONAL INFORMATION

The cycle time is the length of time it takes the system (including GC and data system) to run its complete method and return to a Ready state. This time must include any heat-up or cool-down cycles for the oven and any inlets or detectors, as well as data system processing time and time for external devices, such as a mass selective detector, to be ready.

If the entered time is too short, the Headspace may place vials into the oven too early. When the Headspace sample is ready for injection, the GC may still be Not Ready or in the middle of the previous run. The samples may equilibrate too long. In this case, the action taken by the Headspace depends on the Sequence Actions defined for the method. As a minimum, the software logs the deviation.

If the entered time is too long, it can reduce Headspace throughput. Depending on the Headspace method settings, the Headspace may wait to place vials into the oven.

See article WKB62833 on Split injection technique

See article WKB62831 on Splitless injection technique

See article WKB62933 on PTV injection technique