Packed columns obsolete? [August 3, 2004]
Posted: Mon Aug 30, 2004 6:39 pm
By Dewey Harvey on Tuesday, August 3, 2004 - 06:55 am:
We are considering purchasing a GC with both packed
column and capillary column injector ports. Is there a
future for packed columns?
-------------------------------------------------------------------------------------------------------
By Consumer Products Guy on Tuesday, August 3, 2004 - 08:13 am:
There are a few applications for which we still use packed columns, but we're over 90% capillary. I will say that for one of our applications that the packed column is about $70 and the WB capillary equivalent is about $300. And sometimes one doesn't need additional resolution.
-------------------------------------------------------------------------------------------------------
By anonymous on Tuesday, August 3, 2004 - 12:15 pm:
It depends on what types of analyses you need to do. Our GC has both types of injector ports. We rarely use the packed, except in the analyses of gases. However, there are capillary and megabore columns available for these applications. A packed port can usually be fitted with an adaptor to install a 530 um column, so you're not confined to packed.
-------------------------------------------------------------------------------------------------------
By chromatographer1 on Wednesday, August 4, 2004 - 09:13 am:
You may come across methods you may have to duplicate using packed columns.
Many fixed gas applications are best done (cheap repeatable easy) on packed columns.
It pays to be a boy scout if your company requires you to repond quickly to a problem.
As mentioned above, packed inlets can be converted to direct megabore capillary and micropacked columns quite easily.
-------------------------------------------------------------------------------------------------------
By tm on Friday, August 6, 2004 - 01:04 pm:
I use a packed everyday. There are some analytes that capillary just won't work for.
-------------------------------------------------------------------------------------------------------
By carla on Sunday, August 15, 2004 - 03:27 pm:
@tm:
what kind of analytes do you mean?
-------------------------------------------------------------------------------------------------------
By chromatographer1 on Monday, August 16, 2004 - 06:36 am:
Capillary columns are great, but volatile gases work best on packed columns, especially if you have a TCD detector. Try measuring 1ppm acetylene in ethylene using a capillary column... but not if you want it done fast (<3 min) repeatable (< 1% RSD @ 1ppm) and not subject to RT drift as the column ages.
Capillary columns are sample size limited. Packed columns can handle much larger injections which can be a necessary factor in your analysis.
Use the proper tool for the proper problem. Not every analysis requires 30,000 plates.
Some samples are dirty, why contaminate a $500 column in a few days use when a $100 packed column willl last weeks with the same results.
We are considering purchasing a GC with both packed
column and capillary column injector ports. Is there a
future for packed columns?
-------------------------------------------------------------------------------------------------------
By Consumer Products Guy on Tuesday, August 3, 2004 - 08:13 am:
There are a few applications for which we still use packed columns, but we're over 90% capillary. I will say that for one of our applications that the packed column is about $70 and the WB capillary equivalent is about $300. And sometimes one doesn't need additional resolution.
-------------------------------------------------------------------------------------------------------
By anonymous on Tuesday, August 3, 2004 - 12:15 pm:
It depends on what types of analyses you need to do. Our GC has both types of injector ports. We rarely use the packed, except in the analyses of gases. However, there are capillary and megabore columns available for these applications. A packed port can usually be fitted with an adaptor to install a 530 um column, so you're not confined to packed.
-------------------------------------------------------------------------------------------------------
By chromatographer1 on Wednesday, August 4, 2004 - 09:13 am:
You may come across methods you may have to duplicate using packed columns.
Many fixed gas applications are best done (cheap repeatable easy) on packed columns.
It pays to be a boy scout if your company requires you to repond quickly to a problem.
As mentioned above, packed inlets can be converted to direct megabore capillary and micropacked columns quite easily.
-------------------------------------------------------------------------------------------------------
By tm on Friday, August 6, 2004 - 01:04 pm:
I use a packed everyday. There are some analytes that capillary just won't work for.
-------------------------------------------------------------------------------------------------------
By carla on Sunday, August 15, 2004 - 03:27 pm:
@tm:
what kind of analytes do you mean?
-------------------------------------------------------------------------------------------------------
By chromatographer1 on Monday, August 16, 2004 - 06:36 am:
Capillary columns are great, but volatile gases work best on packed columns, especially if you have a TCD detector. Try measuring 1ppm acetylene in ethylene using a capillary column... but not if you want it done fast (<3 min) repeatable (< 1% RSD @ 1ppm) and not subject to RT drift as the column ages.
Capillary columns are sample size limited. Packed columns can handle much larger injections which can be a necessary factor in your analysis.
Use the proper tool for the proper problem. Not every analysis requires 30,000 plates.
Some samples are dirty, why contaminate a $500 column in a few days use when a $100 packed column willl last weeks with the same results.