Saturday, March 24, 2012

Rapid Analysis of Gaseous and Liquid Hydrocarbons Using Fast GC- Reduces Analysis Times by > 50%,#Fast_GC,#C1-C6_hdrocarbons.#GC

We have used the analysis of C1 to C6 hydrocarbons with a 30M x 0.32mm id with a 5  film to demonstrate the separation of both gaseous and liquid hydrocarbons rapidly while reducing analysis time by more than 50%.

The figure below illustrates the isothermal separation of C1 to C6 HC. A low temperature (35oC) is requires to separate methane from ethane and propane. The detector was the far UV absorbance detector and the analysis time was 15 minutes. This analysis can be sped up using temperature programming but with the long cool down times of most GC ovens, the analysis times can be reduced to about 12 minutes.

Much of the previous work on “fast GC” utilized short (5M) thin film capillary columns to elute solutes quickly and the result is rapid but inferior separations because of the short column. New technology developed at Valco’s capillary column development center where VICI takes polyimide-coated fused silica (FST) and removes the polyimide layer. Then the (FST) is electroplated with nickel. As a result of the superior heat transfer of the electroplated nickel, we are able to rapidly and efficiently heat and achieve excellent resolution for a 30M capillary column.
 These columns can be programmed faster (hundreds of degrees/min)- save 50-90%
 The columns can be reliable started a few degrees above ambient
 These columns cool down faster because of their low mass, so savings are> 50%
Several examples of C1 to C6 HC that are given below demonstrate a > 50% reduction in analysis times:The columns can be programmed faster 50-60o/min and will cool down faster as a result of their low mass. The columns can be reliably programmed from several degrees above ambient which is not possible with most GC/s.

A comparison of a GC with a normal oven and a fast GC column are shown below.

Contact PID Analyzers for more info on “The FAST GC”

PID Analyzers, LLC, 2 Washington Circle, Sandwich, MA 02563; T 1 774 414 5281