Instrument: 3100 Purge and Trap Sample Concentrator
Inert Sample Pathway for the Analysis of Flavor Components
Using a Tekmar 3000
The primary objective of laboratories today is to increase sample throughput while maintaining sensitivity and low cost analysis. An optimum system should be able to split off a percentage of methanol and water, maintain column desorb flows at a specific split ratio, and reduce run times without sacrificing chromatography or sensitivity.
The most commonly used methods utilize either a splitless or split injection technique. The splitless technique used with a narrow bore capillary column typically requires cryofocusing. This method is suited for trace analysis, provides excellent sensitivity, and does not require any expenditure for an open split interface or jet separator. However, you are limited to a small linear working range, lower sample capacity, and cryogenics are often needed. The post-column split technique utilizes a megabore capillary column and eliminates the need for cryogenics. Wide bore columns can handle a larger sample capacity and are suited for the analysis of concentrated samples. Depending on the split ratio, there may be a loss of sensitivity. Another limitation is the cost incurred for purchasing megabore columns and some type of split interface.
The Direct Split Interface (DSI) is a technique that uses a standard split/splitless injection port. It effectively separates all analytes, including the gases, through the use of a pre-column split. No additional costs are incurred, the need for cryogenics is eliminated, and GC run times are reduced to less than 20 minutes. Chromatographic resolution and sensitivity is enhanced through the use of a microbore capillary column, high desorb flows, and Trap Pressure Control (TPC).
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