44
User Information
Introduction to Headspace and to the G1888 Network Headspace Sampler
In MHE, users can encounter two possible situations:
•
GC Cycle Time is longer than the Vial Equilibration Time
The first extraction begins after the Vial Equilibration Time
is satisfied. Each subsequent extraction occurs based on the
cycle time interval.
For example, if Vial Eq. Time = 5.0 min and Cycle Time = 10.0
min, then first extraction is at 5.0 min, second is after
another 10 min, (15 min cumulative, approx.), third after
another 10 min (25 min. cumulative), etc.
•
GC Cycle Time is shorter than the Vial Equilibration Time
The first extraction begins after the Vial Equilibration Time
elapses. Each subsequent extraction occurs based on the Vial
Eq. time interval.
For example, if Vial Eq. Time = 8.0 min and Cycle Time = 5.0
min, then first extraction is at 8.0 min, second is after
another 8 min, (16 min cumulative), third after another 8
min (24 min. cumulative), etc.
The following events take place during MHE with multiple vial
puncture:
1
Multiple extraction method loaded
2
Vial placed in oven
3
Vial heated for vial equilibration time
4
Vial sampled according to event times
5
GC started
6
Vial returned to slot in oven carousel
7
Second heating time started
8
Vial sampled according to event times
9
GC started
10
Vial returned to oven
11
Continue from
(up to number of extractions per vial)
12
Vial returned to tray
medium_standard.book Page 44 Tuesday, February 17, 2004 10:14 AM
