Chromatography Forum

Hello people,
I want to pack my HPLC empty columns (diameter: 2-8 mm; length: 10-100 mm) with zeolites (50-100 µm) to perform adsorption experiments. Now I have struggles with inhomogeneities and therefore, the pressure rises rapidly in the HPLC system. Do you have ideas how I could pack my column more homogeneous?

Sure! Get rid of the smaller particles (dust?) that are causing the problems with elevated backpressure. For particles as large as your zeolites, you could use a sieve for that.

Sure! Get rid of the smaller particles (dust?) that are causing the problems with elevated backpressure. For particles as large as your zeolites, you could use a sieve for that.

thanks for your reply

That's an important point you make and one that I've thought about as well. I have actually already sieved my particle fraction. Do you think that the range between 50-100 µm is too big? What size range would you recommend? Do you have any special tips for sieving? I have classified the solids by dry sieving (unfortunately we don't have wet sieving in the house). The problem with dry sieving, however, is that I still observed a very fine dust fraction (< 50 µm!) in my particle size distribution. I suspect that the dust particles adhere very strongly to the larger particles and are not separated by simple dry sieving. Perhaps the particles break down even further during sieving due to friction and impacts...
Do you or anyone else have any ideas or input on this? Is there a better classification method (air jet sieve?). Does anyone perhaps have any other ideas except for eliminating the dust particles (slurry packing method, hand pumps to pressurize the fixed bed, use of ultrasounic, ..)?