Presentation Profile
A GCxGC Valve Modulator with Hold-Release Primary Column Flow for Long Secondary Separation Time
Currently Scheduled: 1/18/2018 - 11:05 AM - 11:35 AM
Room: Exhibit Hall Classroom (End of 200 Aisle)
Main Author
Huamin Cai - Valco Instruments Co. Inc.
- Stanley D. Stearns - Valco Instruments Co. Inc.
Abstract:
Valve modulators have been used for GCxGC separation for many years. Compared to thermal modulators, it has the advantages of simplicity, low cost, and no low boiling point limit. However, the valve modulator usually has a short modulation period PM because it needs to maintain continuous primary column flow. Consequently, it is easy to cause peak wrap around. In this presentation, we will propose a hold-release primary column flow method to increase secondary retention time. This method uses a valve to make the primary column flow reverse, slow down, and stop during secondary separation. In this way, it makes the sample stay in the primary column longer and gain more time for secondary separation. By using this method, a 20-second secondary retention time or modulation period PM has been achieved with 100% transfer from primary to secondary. A longer secondary retention time can increase the secondary separation power, reduce the requirement of fast response detection, and perform a second dimension temperature program.
