Fast(er) SEC- is there a way to stagger injections and data collection?

ShellyBuhay

<p>We have been looking at ways to speed up our size exclusion assays, for faster throughput for screening of formulation samples.  We have looked at the Acquity BEH SEC column, and found it to work great - immediately cut our run times by at least half, and possibly more as we work to optimize the method. </p><p></p><p>Looking at what else we can do, I recently came across an article that made a valid point- for an SEC column, all of the separation comes between the exclusion limits and the inclusion limits of the column, so it is really unnecessary to collect data until you reach the exclusion limit.  Their idea was to stagger injections; for example, for a conventional column, you would inject, wait ~10 minutes (depending on the properties of your column), and then while you are acquiring data for the first sample where the sample actually separates,  inject the sample again, so that you are constantly collecting data over the ~15 minutes or so where the separation is actually happening (I hope that makes sense).  This would significantly cut run times, and would be really great for rapid screening.</p><p></p><p>Thinking about the options on the UPLC, though, I'm not sure if it would be possible to run the instrument this way.  I'm hoping a more expert user might weigh in as to how it may be done.</p><p></p><p>The paper I was looking at is: J Chromatog A 1216 (2009) 8904-8909.</p><p></p><p>Thanks!</p>

MarcNoble

Marc Noble

Principal Service Specialist

Phone - 800-252-4752 x6220

Mobile - 484-363-7814

Email - marc_noble@waters.com

lizh

Interesting...wait til the rallies to find out...no seriously,we are looking at Multipump config for PittCon, but here's the rub. If only it had been

any other column. SEC could be used with a MALLS detector and I needed to check the backpressure recovery and whether it i feasible. My concern is

that there might be an impact on the column. Anyway I have sent out a call to Beth Gildea and the bio team and I will let you know.

Liz

New message: "Fast(er) SEC- is there a way to stagger injections and data collection?"

Marc Noble

to:

Elizabeth Hodgdon

01/12/2011 01:39 PM

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Fast(er) SEC- is there a way to stagger injections and data collection?

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Marc Noble

Principal Service Specialist

Phone - 800-252-4752 x6220

Mobile - 484-363-7814

Email - marc_noble@waters.com

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PeteClaise

Hi Shelly,

     Thanks for your question.Unfortunately at this time it is not possible to perform this procedure as described in the paper. Empower will not start a new injection, i.e., draw sample, until the previous injection run time is complete.

Best Regards,
Pete

ShellyBuhay

Thanks Pete - that's what I thought, but I wanted to be sure!

Shelly.

Southpaw

That's actually untrue, you can certainly stack injections on Waters systems.  We've successfully done it on the Alliance systems and it should lend just fine to Acquity systems too.  All you have to do is set up two instruments, one that contains the separation module (pumps, column heater, etc) and one that contains the detector module(s).  You can then use the contact relays on the separation module to initiate the detection window and tune your runtime in both the separation and detection "instruments" to have stacked injections.

Feel free to PM me for specific information.

ShellyBuhay

Oh, that's clever!  I can't wait to give that a try (but it will be a few weeks before I can get some time on the instrument).  Thanks for the great idea!