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Hi, I need help to solve the problem of free cyanide determination by ion chromatography. The eluent is a solution of Naoh-100mmol/l and EDTA -0.01mmol/l. As can be seen from the picture, no peak appears when testing a real sample, while at a standard peak it is clearly visible even at low concentrations. If anyone has encountered such a problem I would be glad to share the experience.
Thanks in advance.
https://dox.abv.bg/download?id=d80e53372a#%20
https://dox.abv.bg/download?id=21b483218c#%20
Dear Georgi

What is the real sample?
Be aware that only free cyanide is determined. If bound cyanide is in the sample this cannot be determined.
Dr. Markus Laeubli
Manager Marketing Support IC
(retired)
Metrohm AG
9101 Herisau
Switzerland
Dr. Markus Laeubli,
The sample is tap water and another sample is river water. In both cases I do not know what cyanide is present in the sample. What I'm looking for are free cyanides, not related cyanides. What puzzles me and I don't understand is this baseline breakdown / assuming there are no cyanides in the sample. And it should not be because it is drinking water./
Dear Georgi

I assume the the additional "peak" is a matrix disturbance.
I will check with my colleague which actually works with amperometric detection. and come back to cou later.

Best regards
Markus
Dr. Markus Laeubli
Manager Marketing Support IC
(retired)
Metrohm AG
9101 Herisau
Switzerland
I assume that you are using one of our instruments.
Would it be possible to send me the exported determination files.
to markus.laeubli@metrohm.com

Best regards
Markus
Dr. Markus Laeubli
Manager Marketing Support IC
(retired)
Metrohm AG
9101 Herisau
Switzerland
A fast check on your side would be to spike the water asmple with cyanide to check whether you can recognize a cyanide peak in water.
Dr. Markus Laeubli
Manager Marketing Support IC
(retired)
Metrohm AG
9101 Herisau
Switzerland
I also made a spike to this water. The peak is divided into two symmetries. I'll send you the chromatograms later. Thank you.
Dear Georgi

We had a look to the commatrograms and our final comment (after our internal discussions) are: the baseline disturbance most probably comes from the matrix, e.g. carbonates, meatals etc.
One possibility to lower the the effect could be the use of a longer column (more capacity and more separation).
The other possibility (which we recommend) is applying a distillation step as requested in e.g. ASTM D2036 - 09 (2015), DIN 38405-13.

Best regards
Markus
Dr. Markus Laeubli
Manager Marketing Support IC
(retired)
Metrohm AG
9101 Herisau
Switzerland
Dear mr. Laeubli,
Thanks a lot. I'll try distillation and write about the effect.
Thanks for your time.
Be healthy.

Greetings
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