column suggestion

[tatianak]

GOOD MORNING !!!

I have a methodology for adenosine triphosphate and its breakdown products which employs a microbondapack column (3.9 mm I.D x 30 cm Waters Associate). If I don´t have access to this column. What type and brand can I use instead???

THANKS.
TK

[coquim]

it´s depend on your mobile phase...what kind of m.p. are you using?.
i´ve a method for this too and my column is a c18 250 x 4,6...

Best regards...

[tatianak]

Hello, thanks for your prompt reply, my mobile phase is:

0.04 M potassium dihydrogen orthophosphate and 0.06 M dipotassium hydrogen orthophosphate dissolved in Milli Qpurified distilled water.
Flow rate 2ml/min.

TK

[tatianak]

it´s depend on your mobile phase...what kind of m.p. are you using?.
i´ve a method for this too and my column is a c18 250 x 4,6...

Best regards...

Hello, thanks for your prompt reply, my mobile phase is:

0.04 M potassium dihydrogen orthophosphate and 0.06 M dipotassium hydrogen orthophosphate dissolved in Milli Qpurified distilled water.
Flow rate 2ml/min.

TK

[JGK]

Looking at a table o Hydrophobicities of varying column types, µ-Bondapack columns have a ditinctive retention profile.

You could try

Spherisorb ODS1
Exsil 100 ODS or ODS1
Nucleosil 100 or 120 ODS
Hypersil ODS
LiChrospher ODS

[AdrianF]

Is your mobile phase only aqueous - no organic?

[Uwe Neue]

I have stated this before: microBondapak C18 has a unique surface. If you will be successful with another product is questionable. The column is available form Waters Corporation.

[AdrianF]

I have come across this reference which should help

http://www.sigmaaldrich.com/Graphics/Su ... 0/4541.pdf

Uses Supelcosil LC-18-T

[tatianak]

Is your mobile phase only aqueous - no organic?

YES, IS A METHOD BY JOHN M. RYDER 1985. J. Agric Food Chem

[AdrianF]

I would suggest you definitely look for a different method as most reverse phase columns suffer phase collapse if used with totally aqueos mobile phases.

PS I agree there must be something a bit special about microbondapak for it to have survived so long.

I think my down on Waters must have come from struggling with WISP autosamplers in the past!!

[shaun78]

Phenomenex Bondclones are a great substitute to bondapacks.

Moving into newer column technology, Phenomenex Gemini and Water's XTerra are good substitutes to bondapacks and bondclones.

The Gemini or XTerra would be preferred due to the fact that the hybrid polymer support of these columns will allow them to deal with 100% aqueous conditions more favorably than the others.

[cyanogen78]

I can't imagine how one RP & endcapped column like microBondapak could provide reproducible results with 100% aqueous mobile phase. All the producers of HPLC columns claim that their RP columns with embeded polar were designed exactly for these cases. Some examples are Bonus-RP & SB-Aq (Agilent), Synergi Polar-RP & Fusion (Phenomenex) etc. Most of the vendors have such RP columns for work with 100% aqueous phase and highly polar compounds

[SIELC_Tech]

You might want to try this:
http://www.sielc.com/compound_257.html

Also this article just came out for analysis o phosphates:
"Direct stability-indicating method development and validation for analysis of etidronate disodium using a mixed-mode column and charged aerosol detector". Journal of Pharmaceutical and Biomedical Analysis, Vol. 46, No. 4, pages 639-644 (2008) by Liu, X.K., Fang, J.B., Cauchon, N., Zhou, P

Contact me if you have any questions.

Regards,

Vlad

[Uwe Neue]

microBondapak C18 does work in 100% water. Also modern fully endcapped C18s have been designed that work in 100% water. There are two examples in the Waters portfolio: Atlantis dC18 and Atlantis T3.

So if you want a modern equivalent of microBondapak C18, it is worth trying either one of the Atlantis packings. However, I still maintain that the better approach is to stick with the original. No changes, no headaches...

[AdrianF]

Uwe, what evidence is there that microbondapak suffers no phase collapse when exposed to 100% aqueos mobile phase.