We have a packed column method which continually gives us trouble with tailing peaks, even on a new column. As several runs are put on the column, the tailing gets much worse and reconditioning of the column may bring it back for a few more runs, but thats about it.

The method uses a glass column (2m x 2mm) with HayesSepQ packing. The analytes are solvents (IPA, Ethanol, ACN, MeOH) and particularly the alcohols tail. The method follows the USP (Section 611) which specifically says "glass column".

I suspect that some of my problem is due to activity issues (especially since ACN does not tail so much compared to the alcohols). I wanted to look into a packed metal column with special deactiviation (i.e. Restek SilicoSmooth).

My question is whether this specially treated metal column can pass for a glass column in the eyes of the USP/FDA?

Also, any suggestions on how to improve the tailing problems of these peaks (also considering that we only have so much wiggle room with the FDA).

Thanks in Advance

Kevin Kolodsick
Analytical Method Development
Ferndale Laboroatories
Ferndale MI, USA

Kevin,

The problem lies not in the glass column, nor in the cleanliness of the packing, but in the distribution of the packing in the column.

All porous polymers are difficult to pack uniformly. If low density areas are found in the bed, the alcohols will tail. Tailing factors of 1.2 to 1.22 are normal for ethanol in this column if packed uniformly.

Supelco is aware of this problem and we have resolved it. Customers have confirmed the solution in beta test.

Contact me or Technical Service at Supelco for help. 1-800-359-3041

Rodney George
Senior Research Chemist
Gas Separations Research
Supelco
595 North Harrison Road
Bellefonte, PA 16823
1-814-359-5737