Glass wool in the inserts of split injectors for capillary GC?

✍ Scribed by Grob, K. ;Neukom, H. P. ;Hilling, P.

• Publisher: John Wiley and Sons
• Year: 1981
• Tongue: English
• Weight: 593 KB
• Volume: 4
• Category: Article
• ISSN: 0935-6304
• DOI: 10.1002/jhrc.1240040502

✦ Synopsis

Abstract

It has been reported that glass wool packed tightly into the glass liner of a vaporizing injector used in the splitting mode considerably reduces the standard deviation of the results obtained, because of improved evaporation of the sample prior to reaching the split point at the capillary column entrance. This finding could not be reproduced on using the same sample composition as reported in the literature, i.e. methanol/2‐ethyl‐1‐hexanol (1:1).

The standard deviations obtained were between 3 and 10% (depending on the conditions selected) and were not influenced significantly by the introduction of glass wool.

The peak area ratio (methanol/2‐ethyl‐1‐hexanol) was found to depend on a number of parameters, such as: injector temperature; glass liner internal diameter; syringe handling technique; the relative position of the syringe needle exit and capillary column entrance; the sample volume injected; and the packing of the glass liner. Generally, the area ratio deviated further from the correct one (determined by cold on‐column sampling) when the glass liner was packed with glass wool.

On the basis of the results, it is speculated that either a complete evaporation of the sample should be achieved (which appears to be impossible under the conditions we used) or, alternatively, the sample should be given the least possible opportunity to evaporate, thus allowing it to enter the column in the form of droplets. The results were worse in terms of precision and accuracy the greater the partition of sample components between the liquid (droplet) and vapor phase. It is concluded that the use of evaporation aids such as glass wool cannot be generally recommended.