Discussion Category:  Titrators

Error: EP1 Missing

When trying to determine Mercaptain-sulfur using Karl fischer Titration, it display The EP1 is missing , what could be the problem?

GILBERT

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GILBERT
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avatar placemarkReply by
lae

Dear Gilbert

EP1 missing means that the algorithm did not find an end point. Therefore nor result to be calculated.

Karl Fischer titration is primarily a determination of water. The raction of R-SH with iodine is a side reaction. If you apply Karl Fischer titration to the determination of R-SH different method parameters might be required to find the end point.

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GILBERTReply by
GILBERT

Hi Lae

Thanks for your informations

Can you please advice, what method can i add/use so that i can determine R-SH and reach the end point?

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avatar placemarkReply by
lae

I am not a titration nor a KF specialist, therefore cannot realy help.

I also ckecked our applications. But I only found water determinations.

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Metrohm_SimonReply by
Metrohm_Simon

Dear Gilbert

Depending on your sample you find more endpoints.  If there is only mercaptans present you find one EP. If there is also H2S beside the mercaptane present you find two EPs. As i dont know your method and your sample composition i can not give you further hints. You find some more information in our application bulleting 135/3 -> Potentiometric determination of hydrogen sulfide, carbonyl sulfide and mercaptans in petroleum products at the metrohm website:

http://www.metrohm.com/en/applications

Choose method: titration
Fulltext search: mercaptans

We do a potentiometric titration with a Ag Titrode and silver nitrate.

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GILBERTReply by
GILBERT

Hi Simon

Thanks for your information,

But the problem is still there.

Can you please help me on how i can workout the issue (trouble shooting Procedure Document).

NOTE: The Sample to be tested : MOGAS

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GILBERTReply by
GILBERT

The method is : ASTM D4294

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avatar placemarkReply by
lae

Dear Gilbert

ASTM D4294 has nothing to do with titration.

So best is to check the Application Notes and the Application Bulletin resulting in Simon's search:

http://www.metrohm.com/en/applications

Choose method: titration
Fulltext search: mercaptans

If that does not help, contact your local Metrohm represenative for support.

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GILBERTReply by
GILBERT

thank lae, Apologising for typing erroe

will work again and again with the simon notes

.

cheers

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