Plate Counts - Single Column vs. Column bank

[sturgman]

Hello everyone,
I have three new old waters styragel columns. They look like very old unused columns packed in DMF. We could use DMF columns in my lab but I never inaugurated a new set of columns before. Waters suggest measuring the efficiency of the columns by measuring the plates and they provide common plate counts for individual columns. A few questions:

1. If I use a column bank can I measure the plate counts and find comfort if the number of plate counts is the sum of the individual ones suggested by Waters?

2. If Im using the three columns together for measurements should I bother measuring individual plate counts for reference?

Any help would be greatly appreciated. Thanks!

[Uwe Neue]

There is not a good way to check, if an ancient column has dried out or not. Therefore I would start every column up individually in DMF, with the usual precautions, and then measure the plates. If they are in the ballpark, you can connect the columns in series. While plate counts are not additive, you might get more plates from the column bank than what you expect to get by adding the individual plates. In the future, you should always measure the plate count of the bank.