EDTA as mobile phase for HPLC

[RubyG]

Hi,
I'm Roberta and I am a new registered in this forum.
Plese, can someone tell me if it is possible to use EDTA (5 mM) as mobile phase in HPLC? somenone told me that there are some compatibility problems for the metallic part of this kind of instumentation.

Thanks a lot.

R.

[carlo.annaratone]

as far as I can tell, the only problem might be in the case you use a detector such as MS or ELSD which require volatile mobile phases, otherwise should be just fine. In doubt, can't you lower the concentration? I do not know why you need it, but 5 mM seems a lot to me

[RubyG]

as far as I can tell, the only problem might be in the case you use a detector such as MS or ELSD which require volatile mobile phases, otherwise should be just fine. In doubt, can't you lower the concentration? I do not know why you need it, but 5 mM seems a lot to me

Ok, thanks for your replay.
The EDTA mobile phase 5mM is used because I've found this value in bibliography for my measurements, but probably I should reduce this and try first with lower ones.

Thanks

Roberta

[carlo.annaratone]

If literature says that EDTA is used in your analysis in HPLC, then it should work in HPLC!

[RubyG]

If literature says that EDTA is used in your analysis in HPLC, then it should work in HPLC!

Of course! but they used EDTA not on HPLC instrument but on Ion chromatograph so is not the same thing.
Bye.

[carlo.annaratone]

EDTA can be used on IC instruments to remove trace of contaminant cations that may "stick" to the column and alter the separation. Maybe it's not necessary in HPLC. The only few cases where I found use of EDTA in HPLC are:

Myint, K. T., Uehara, T., Aoshima, K., & Oda, Y. (2009). Polar anionic metabolome analysis by nano-LC/MS with a metal chelating agent. Analytical Chemistry, 81(18), 7766–72. http://doi.org/10.1021/ac901269h

Pesek, J. J., Matyska, M. T., & Fischer, S. M. (2011). Improvement of peak shape in aqueous normal phase analysis of anionic metabolites. Journal of Separation Science, 34(24), 3509–16. http://doi.org/10.1002/jssc.201100607

Asakawa, Y., Tokida, N., Ozawa, C., Ishiba, M., Tagaya, O., & Asakawa, N. (2008). Suppression effects of carbonate on the interaction between stainless steel and phosphate groups of phosphate compounds in high-performance liquid chromatography and electrospray ionization mass spectrometry. Journal of Chromatography. A, 1198-1199, 80–6. http://doi.org/10.1016/j.chroma.2008.05.015

Köster, J., Shi, R., von Wirén, N., & Weber, G. (2011). Evaluation of different column types for the hydrophilic interaction chromatographic separation of iron-citrate and copper-histidine species from plants. Journal of Chromatography. A, 1218(30), 4934–43. http://doi.org/10.1016/j.chroma.2011.03.036

[RubyG]

EDTA can be used on IC instruments to remove trace of contaminant cations that may "stick" to the column and alter the separation. Maybe it's not necessary in HPLC. The only few cases where I found use of EDTA in HPLC are:

Myint, K. T., Uehara, T., Aoshima, K., & Oda, Y. (2009). Polar anionic metabolome analysis by nano-LC/MS with a metal chelating agent. Analytical Chemistry, 81(18), 7766–72. http://doi.org/10.1021/ac901269h

Pesek, J. J., Matyska, M. T., & Fischer, S. M. (2011). Improvement of peak shape in aqueous normal phase analysis of anionic metabolites. Journal of Separation Science, 34(24), 3509–16. http://doi.org/10.1002/jssc.201100607

Asakawa, Y., Tokida, N., Ozawa, C., Ishiba, M., Tagaya, O., & Asakawa, N. (2008). Suppression effects of carbonate on the interaction between stainless steel and phosphate groups of phosphate compounds in high-performance liquid chromatography and electrospray ionization mass spectrometry. Journal of Chromatography. A, 1198-1199, 80–6. http://doi.org/10.1016/j.chroma.2008.05.015

Köster, J., Shi, R., von Wirén, N., & Weber, G. (2011). Evaluation of different column types for the hydrophilic interaction chromatographic separation of iron-citrate and copper-histidine species from plants. Journal of Chromatography. A, 1218(30), 4934–43. http://doi.org/10.1016/j.chroma.2011.03.036

thank you again so much for the assistance
R.

[KM-USA]

I'm currently assaying for citric acid.

Citric acid peak shapes seem to get worse compared to a new column, and tricks like injecting 100 µl 0.10M EDTA several times before injecting standards and samples seems to help. So does using micromolar amounts of EDTA in my acid mobile phase (conductivity detector). Also helping is pumping the mobile phase in a recycle mode at slow flow back into the reservoir between uses, keeping the column equilibrated.

[Markus Laeubli, Metrohm]

The initial question will be "what does EDTA stand for?"
If it is the (Ethylenedinitrilo)tetraacetic acid than it is quite little dissolved in water. If it is e.g. the disodium salt then thereis a very good solubility. There fore you need to be careful with suppression in IC as this converts the salt into the acid.

EDTA is a complexing agent and complexes a lot of di- and trivalent cations. We use it mainly as complex builders in applications where ultratraces of heavy metals are disturbing. Buth then in much lower concentrations.
EDTA will not harm the system neither HPLC nor IC.

Finally the use of EDTA depends on waht you want to be separated and how you want to detetct your components.

[RubyG]

thank you for the comprehensive reply.

The initial question will be "what does EDTA stand for?"
If it is the (Ethylenedinitrilo)tetraacetic acid than it is quite little dissolved in water. If it is e.g. the disodium salt then thereis a very good solubility. There fore you need to be careful with suppression in IC as this converts the salt into the acid.

EDTA is a complexing agent and complexes a lot of di- and trivalent cations. We use it mainly as complex builders in applications where ultratraces of heavy metals are disturbing. Buth then in much lower concentrations.
EDTA will not harm the system neither HPLC nor IC.

Finally the use of EDTA depends on waht you want to be separated and how you want to detetct your components.

[Klaus I.]

I have only bad experience using EDTA. After about two days the baseline becomes wavy and it needs several days to clean the system. We have observed this problem every time in QC-lab with Alliance systems.

I have figured out later that using EDTA was most probably unnecessary. I have never observed problems by using a simple formic acid buffer without EDTA for lc/ms measurements. But the inlet was an Agilent 1200 SL and I am not sure if the instrument types make differences.

[RubyG]

Thanks, the first results are not good even modifying the molarity of the eluent or the pH (there is no reproducibility of the data). I think the next step will be to change eluent (probably with Oxalate)....

Thank you all.
R.

[carlo.annaratone]

Could you give us more details about the protocol you are using? RP, HILIC? eluents? detector?

[RubyG]

Could you give us more details about the protocol you are using? RP, HILIC? eluents? detector?

I'm using HPLC with DAD detection and Na2-EDTA as mobile phase. I need to chelate same rare earths and separe them on anionic column. But the data are not reproducibles so I'll try to chenge eluent.

thanks
R.

[carlo.annaratone]

beware that if you are trying to get ion exchange running on HPLC (and not IC) hardware, you will always have the problem of steel leaching. Depending on the level of you analysis (trace or abundant compounds) it might work or might be a no-go