The Column - February 2007 - (Page 10)

Zosimus The Column February 2007 Connection Difficulties Zosimus investigates complaints about column fittings. In a recent visit to a very high-profile laboratory I was amazed to hear so much criticism over chromatography instruments and accessories. And I don’t think it was because these people were a bunch of whingers. The most significant complaint was about HPLC column fittings and how they are connected to the new “state-of-the-art” HPLC instruments. One technician said: “Why, with all the progress I see in other areas, are we still using these old nut and ferrule fittings? Surely some bright spark could design a simpler, better system. To successfully connect a column you need three hands: two for the nut and ferrule spanners and another to hold the column. Could someone please tell instrument manufacturers that technicians do not have, as yet, three hands.” These comments led me to re-examine current LC and GC columns and I found that what the technician had said was very true. I do not see any change in column coupling — apart from reductions in size — since the very first columns produced by Knox and Kirkland was way back in the 70s! And I actually think that things have got worse since then. More skill is now required to couple the new capillary columns onto the new instruments than was ever required to connect the old classic 4.6 mm i.d. columns. I was recently given the opportunity to test this. On a classic HPLC I connected a 4.6 mm i.d. column and obtained a fairly decent chromatogram from a standard test mixture. The technician removed the column, reconnected it and then re-ran the test mixture to only get 5000 plate/metre more in efficiency. I was then asked to connect a 1 mm column onto a capillary instrument. Apart from it taking a long time, my hands were not flexible enough to get into the corners they were expected to; eventually, I managed to connect the column. On running the same test sample it would be an exaggeration to say a reasonable separation was obtained. The technician removed the column, reconnected it, ran the test sample and then achieved an acceptable chromatogram. I did not realize there was still so much skill required to connect LC columns onto an instrument. But what has been written about this? I cannot find anything. I can find article after article on different packing materials but no reviews or papers on different column couplings. I thought I may find something in the Column Watch articles written in LC•GC Europe, but no, these articles like all the others concentrate on packings and not on the hardware. I did find many research articles on column shapes but no comments on how these are connected onto instruments. So, as I cannot find a single article on connecting columns onto instruments let me make an offer: If anyone would like to send me results or comments please do so and Zosimus will write and publish the findings. 10 Author: Zosimus E-mail:

Table of Contents for the Digital Edition of The Column - February 2007

Market Trends and Analysis
Biodiesel - The Alternative Fuel
Biodiesel (FAME) Analysis by FT-IR
Tips and Tricks: GPC/SEC

The Column - February 2007