Column packing

[jusuom]

Nowadays, HPLC are slurry packed already in the factory. Is it so that in the 1970's the liquid chromatographists packed their columns themselves? Or just partly so?

[Gerhard Kratz]

Also in the 1970s prepacked HPLC columns were sold, beside the bulk packing material to some companies who packed by themself. Fortunately that is with newer packing materials no longer possible because the manufacturers are only selling prepacked columns, and no longer the bulk. If you ever transfered a method from one country to the other and your partner had a different column packer or packed by himself than you are aware of all the problems that can pop up!

[Andy Alpert]

Let me qualify Gerhard's comments. In addition to prepacked columns, our company does sell modest amounts of bulk material to customers who want to pack columns for their own use. This is particularly important to people who like to pack their own capillaries. Packing columns requires somewhat specialized equipment. Without it, problems certainly can pop up, as Gerhard points out. There are some other companies that will sell bulk material too, but you have to look around for them.
Why have many companies stopped selling bulk material in addition to packed columns? It's less profitable while you still have all the responsibility for the reproducibility of the product (at least, that's how the customers see it). No company that sold bulk materials as its main product line has survived.

[sepscientologist]

Kudos to Andy for selling bulk in addition to packed! Most people won't bother to pack their own columns
but thanks, Andy, for giving people the option to roll their own if they want.

[jusuom]

What was the situation when, say, uBondapak or other material of the early/mid 70's was introduced? Was it mostly sold in pre-packed form?

[Andy Alpert]

Some of the manufacturers in the 1970's would sell their materials in bulk; certainly more so than now. Typically the prices were extortionate; so high that the manufacturer made as much profit selling the bulk material as they would have made if they'd packed the same amount of material into a column first. While that is a viable model for being able to make a living as a bulk material vendor, the arrangement was obviously lacking in charm for the potential customers. I might note as well that an appreciably higher percentage of end users packed their own columns in the 1970's than is true today, which is another reason why there's less interest in and availability of bulk material for direct sale.

[tom jupille]

I suspect there are a number of factors at work here. The early seventies saw a big "paradigm shift" with HPLC: from >40 micron packings and "roll your own" columns to <10 micron pre-packed columns. Particles bigger than about 40 microns can be successfully dry-packed ("rotate, bounce, and tap"). Below that size, they have to be slurry-packed which involves quite a bit of art. I can remember table-thumping discussions as to the relative merits of balanced-density slurry versus viscosity slurry and up-flow versus down-flow packing. Even if the packing material were free, there is a non-trivial investment in getting the technique right.

I used the phrase "roll your own" on purpose; can you imagine how many fewer people would smoke if packaged cigarettes were not available?