I doubt it will, as long you properly correct for potential Ca impurities in EDTA

It will effect the calibration simply by creating variable matrix effect due to high level of Na, this is especially the case with the ICP-AES, which is often not internally standardised. One could use matrix-matched standards to avoid it. As for the ICP-MS measurements it is important to make sure the correct collision-reaction mode and correct isotope for Ca is chosen.

Like Ilia, I believe that if you prepare an appropriate EDTA-containing blank, use appropriate internal standard, difference will likely be negligible.

Please digest the solution with Nitric acid which removes EDTA / any organic matter. Then your solution will not have any interference

Unfortunately I can not answer your question. However, I do describe a simple experiment that you can carry out in order to demonstrate the existence or not of some effect of EDTA on analytical signal of calcium.

Please, let me know

Best regards

Mario

If you have a high content of calcium, you will affect the calibration and creating variable matrix effect. However, with low calcium content in your sample, the EDTA has a very limited effect on the Ca measurement. note: the very high concentration of EDTA in your sample will affect the measurement of the most elements and not only the calcium.

Best wishes

Jamal

The advantage and, simultaneously, the problem of Ca analysis by ICP is the very high sensitivity for this element (ppt). So on the one hand it depends on the concentration level you are interested in. On the other side you can work with extremely high dilutions, which helps to avoid matrix effects which could be caused by Na and, especially the organic load (which at higher conc shifts the plasma characteristics). When doing dilutions you will be aware of the ubiquitous character of Ca, which makes extremely challenging to have pure distilled water, pure acids (HNO3), and clean vessels (prefer PFA; avoid lab glass). When working with MS you have hopefully a Hydrogene collision-mode to avoid the Ar-interference (if not go to ICP OES). My approach would be the following: a) perform a "normal" calibration curve (0,1 N HNO3 solution) in the lowest possible reliable conc range; b) make an extreme dilution of your EDTA-solution with your 0,1 N HNO3 solution (keeping in mind the pitfalls of ubiquitous Ca in e.g. also the lab air); c) analyse the diluted EDTA-solution using standard addition method; d) match the slope of the standard addition curve with that of "a)". At the very high dilution of "b)" both slopes are expected to be identical, indicating that you have no interferences by organics (or Na). If so, you can compare your diluted EDTA-solution with the zero-value of your  "normal" calibration line  to retrieve the Ca-conc of your EDTA. High dilution (with all diligence) to suppress interferences from "difficult" matrices was best in my experience and I hope it will do in your case too.

Good luck (and be aware of the ubiquitous Ca-contamination pitfalls)

D. Zachmann

EDTA   as such and Na  definitely  will have matrix effect in ICP-MS analysis and more so when you have  Na conc. > 200 ppm. EDTA  effects can be minimised  by adding EDTA  in calibration std ( matrix match)  and using internal standard. adding sodium in standard  also will help but what extend the suppression or enhancement of analyte signal  has to be studied in your  instrument.

R.Krishna Prabhu

i think at 9000 k the temperature will destroy the bond between edta-ca. however the only factor affect will be the matrix

you should doped EDTA over substrate. then you can use ICP . because high temperature  destroy the EDTA.

There's no need for the MS. In case of Ca you have to dilute your samples and add the same amount of EDTA to your standard solution to match the viscosity and you must optimize your system (torch, plasma, power) for the Ca determination. Sometimes a internal standard is needed to achieve best results.

As mentioned by others the calibration should be done at EDTA concentrations that match the EDTA concentrations in your samples. Nevertheless the presence of organic carbon in the matrix can cause signal enhancement due to changes in the ionization equilibrium in the plasma. You may want to vary the concentration of EDTA to check for this. This paper may be helpful:  “Kralj, P.; Veber, M. Investigations into nonspectroscopic effects of organic compounds in inductively coupled plasma mass spectrometry. Acta Chimica Slovenica 2003, 50, 633-644.”

Hi All,

I am very appreciated for all of your great suggestions!

I finally solved this problem.

Actually I used Atomic absorption spectrometry (AAS) instead of ICP analysis.

I have not observed any signficant effect of EDTA on calcium Measurement when the concentration of EDTA was less than 1% (since above 1%, it would form precipitations when acid was added).

For my samples, it needed to be diluted at least 40 times, the effect of EDTA thereby would be even low.-

Finally I got good results with respect to calcium content determination by AAS. I guess it should also Work for ICP.

I have samples with vinegar and 17 % EDTA (separately) which has to be analyzed for calcium in ICP-MS. Can anyone please suggest how should I proceed then?