Chromatography Forum

Hi
I have two columns from phenomenex having “Batch No”, while having different “Serial No.” one of this columns is showing bad profile (in terms of resolution and peak shape) while other is fine.

Was wondering does different serial no indicate that its column belonging to different lots ?? what does same batch no. on both the column indicates ???

Serial No. should be unique for each column.

The same batch no could indicate, that they were produced in the same week/month/year. Or they used the same material from the same stock. Or anything else.

You should contact phenomenex if you really want to know that.

Batch probably refers to the lot mark of the stationary phase that the column was packed with.

Batch number is for the packing material. Depending on the batch size several hundreds or thousands columns can be packed with the same batch of packing material.
Serial number of a column MUST be unique. From the serial number manufacturer can tell you what lot of hardware was used, who was involved in the packing process, what day it was packed, what was the minimum and maximum temperature that day, relative humidity, all such parameters are monitored and are linked to the serial number of the column.
So, please ask the manufacturer to find out if there are, if, any differences between both columns.
Column packing and column testing is done following an SOP, but involved are human beeings. And humans are supposed to fail, not always, but sometimes. Adam took the apple from Eva and since that time we have such problems............
Out of 1000 columns one can not show a good performance. I'm sure the manufacturer will provide you with an explanation and will offer you a new column. Good luck.

Check the pressure!

I’ve seen this problem. And since the stationary phase is the same as mentioned above, there is this possibility that the 2 columns didn’t get the same amount stationary phase under the packing.
If you see pressure difference between these two columns I’d bet the better performing column is the one that generates higher pressure.

Best Regards

Dear Danko,

possibility that the 2 columns didn’t get the same amount stationary phase under the packing. That is an impossibility. A column with less packing material would not pass the QC test.
The COA is shipped with the column. If RT and number of theoretical plates is within the specification the column is well packed.
Customer should do the same test as mentioned on the COA to see how the performance has changed, what ever is the source for the change.

Dear Gerhard,

The premise here – as I understand it – is not an actual change from one level of performance to another. I understood the situation as follows: 2 new columns packed with the same batch stationary phase, performing differently.
Regarding different performance (same brand, same batch etc.) is not that unusual – I’ve seen it a lot of times. Will not mention the brands that are most likely to exhibit that, but some are worse than other
The specification limits set by the manufacturers are often so wide and are determined using so easy to separate compounds that I wouldn’t even bother to read them.
My approach is: Test the column with what you’re intending to use it.
Finally: What if there is a significant pressure difference – as I’ve seen it in a number of cases?
I don’t think, even the manufacturers would insist that it’s an impossibility as you put it. Only in a perfect world

Best Regards

Dear Dancho,

I agree with you, column testing is the only way, first with the standard reference materials and than with the compound you are looking for. Resolution of 2 peaks is always a good thing to see.
Over the years the specifications for HPLC columns are more narrow than they were. Particle size distribution, pore size distribution, bonding density are the most common parameters to be tested.
Batch to batch reproducibility is essential to play in the premier league. And column to column reproducibility a must.
But you are right. Many, many years ago I saw a brand new RP18 column at a customer without a frit on the column head. But this column was not packed by the original manufacturer. Klaus Unger's team tested a lot columns to see how much packing material they have packed into them. Many years ago.
But still I must say that over 90% of all column complains are not related to the column!
One example please allow me to give you: 60cm long SEC column was installed late afternoon and in the morning this column was bended. Customer complained and asked me if we have used bad quality steel for the column hardware. We asked him to provide photos. The 60cm column, the column box and the 30cm column were bended the same way. I told the customer that he should avoid to do Bodybuilding with the columns, but anyhow, I gave him replacement for both columns.
Have a nice afternoon.
Do you attend Pittcon this year?

Funny story – the one with the bended column.
Maybe there wasn’t enough space in the column compartment so the user “optimized” the design

Unfortunately I’m not going to Pittcon this year. I’m involved in a heroic struggle of optimization of a number of analyses for a certain company I’m consulting for, for the time being and everything is urgent
But I’m sure I would’ve liked to say hello to you.
Have I nice time and please tell us about any new trends afterwards.

Best Regards

Perhaps one of the columns has dried out. Re-wet with high% organic, then do routine QA.