Dear everyone, I had a GC seminar yestoday. The introducer recommened water as the solvent for GC-FID analysis when analyzing solvent residues in Pham industry. While in Agilent manu the water
is not used as solvent for GC. Which idea is more
feasible?
Thank you.
Michelle

Using water as solvent in GC analysis is possible, often convenient and sometimes necessary (dosing solvent traces in water for instance).
However, it is not so easy.
* Water produces a very large amount of vapor in the inlet; try to minimize injection volume.
* Water can deteriorate fragile colums, mostly polar columns; however modern capillary bonded "wax" phases can accomodate water.
* Water can blow off the flame when reaching the FID.
* peaks that coelute with water (which is not seen by the FID) can be distorted/tailing, mainly alcohols.

Michelle,

Water has historically been used for trace solvent analyses in pharmaceuticals, since often drugs are salts and water soluble.

The use of Plot, Scot, and FSOT capillary columns has not replaced the use of glass or FS coated SS columns filled with a porous polymer bead packing.

Durability, linearity, COST, and ease of use are primary attributes of these packed columns.

Many firms who abandon packed columns often replace them with SPME fibers to do residual solvent analyis with capillary columns.

Static Headspace is another technique which can be used to determine very low or high amounts of residual solvent quite easily. Both packed and capillary columns can be used with HS.

I would be glad to assist anyone who would care to discuss their analytical problem. I have extensive experience with all these techniques.

Rodney George
Senior Research and Development Scientist
Gas Separations Research
Supelco
595 North Harrison Road
Bellefonte, PA 16823

814-359-5737 voice
814-359-5459 fax
rgeorge@sial.com

thank you, Beppe and Rodney.
And Rodney, Could I send you mail for discussion about the use of SPME?
Michelle

Yes please do.

Rodney