I am looking for advice on how to prevent tailing on a DB-5 or similar column when studying trimethylsilated compounds such as organic and amino acids as well as sugars. Is there a particular conditioning proceedure that may be helpful?
Thank you

You should expect a certain amount of tailing on a non-polar phase such as DB-5 when analyzing compounds with polar groups. Using a thicker phase may help, but the best bet is to use a column with a higher polarity. There are also specially deactivated columns for use with acidic or basic compounds to reduce tailing. The best idea is to go to column manufacturers catalogs or web sites and see what columns they have used for similar analyses. Check the literature also. DB-5 is a good general purpose column, but it is not the best for all applications. In my previous job I had about 20 columns with a variety of dimensions and phases to handle the variety of analyses we had to do, and it was important to match the column to the analysis for the best results.

After trimethylsilylation, the compound should be nonpolar, and chromatographed on a nonpolar phase such as DB-1 or DB-5. I think the GC and column need to be optimized or cleaned.