Chromatography Forum

Hi @ll,

i have a question concerning a Restek RT-Msieve 5A Column (Cat. # 19725, 30m, 0.53 mm), which we are using in our institute. I use the column to detect low hydrogen concetrations (< 0.1%) and i made the experience that i recieve the best chromatogramms and peak shapes with high column flow rates. So my question is what is the maximal column flow (in mL/min) i can use without running the risk of damaging the column.

thanks a lot!

0pfer

The people who know the most about Restek columns are Restek - they have a technical enquiries dept, drop them an e-mail.

Peter

thats what i did...

25 ml/min is the maximum. maybe someone needs this info..

25 ml/min doesn't sound excessive for a megabore column.

25 mL/min is quite high.

The column volume of 30m x 0.53mm is 6.62 mL. The recommended maximum flow rate is therefore 3.75 column volumes per minute or a dead time of 16 sec.

Translating that to an average linear velocity yields 187.5 cm/sec.
That's fast!

Bill

The maximum practical flow often is a function of the complexity of the separation required. If you have a complex sample with a large number of components of interest you will probably have to operate close to optimum linear velocity, which for a 0.53 mm column is around 4 to 5 mL/min. If you have a few well separated compounds, then higher flow rates and linear velocity will speed up the analysis while still resolving the compounds of interest. I often operate in the range of 40 to 60 cm/sec as a starting point when developing methods.