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Re: Chelation with EDTA
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Bodo Mysliwietz
Apr 2, 2013, 3:01:31 PM4/2/13
to
Am 29.03.2013 02:05, schrieb JD:
> Would someone please answer the following three questions about the chelation
> compound Ethylenediaminetetraacetic acid (EDTA). This is for my personal
> knowledge and is not for any exam or homework.
<laugh> It's Ok ;-)
> 1. If an aqueous solution of EDTA is poured into another aqueous solution
> containing a metal compound (such as Iron sulfate), does the EDTA separate the
> Iron ions from the sulfate ions by binding just to the Iron ions
EDTA encloses the metal ions.
It's German website but one figure should tell more than thousand words:
http://de.wikipedia.org/wiki/Chelatkomplexe
> and the sulfate
> ions remain behind in the aqueous solution?
Yes.
> 2. Does the metallic compound that is to be sequestered by EDTA have to be in a
> solution like water that separates the compound into ions before it can be
> sequestered by EDTA?
I am not specialist for inorganic chemistry but i guess you are on right.
> Can EDTA work in an ethanol solution containing an
> organo-metallic compound if the ethanol solution does not dissolve or
> disassociates the compound into ions.
I don't think so.
> 3. Lets say that we have a trace amount (picogram) of a chemical compound on the
> surface of paper in chromatography that we need to locate. But because of its
> trace amount, its optical density precludes a color reaction that we can see
> with the naked eye. Can EDTA be used as a bridge to attach itself (bind) to the
> trace amount of chemical compound and concurrently to a larger amount of another
> chemical compound that can readily give a color reaction with a reagent. In this
> way, the trace amount of chemical compound (which is too limited in amount to
> give a color reaction that can be seen with the unaided human eye) can be
> detected and located by a color reagent reaction with the larger attached
> compound?
For some metal other reagant can be used. I remember a very sensitive
proof for Aluminum using Morin in Acetic Acid and ultraviolet light.
> In other words, can EDTA serves as a bridge or connection between the
> two different chemical compounds such that the color reaction to one compound be
> used to detect and thus locate a smaller picogram compound on a paper substrate?
To make a long story short: You want to use EDTA as a kind of intensifier?!
> Any help would be apprecaited!
Because it is a quite interesting question i do cross post to German
speaking group. It's a little bit more traffic over there - and the
chance is good that the friend try to answer in english.
--
Glï¿œck Auf - Bodo Mysliwietz
----------------------------------------
http://www.labortechniker.de/
> Would someone please answer the following three questions about the chelation
> compound Ethylenediaminetetraacetic acid (EDTA). This is for my personal
> knowledge and is not for any exam or homework.
<laugh> It's Ok ;-)
> 1. If an aqueous solution of EDTA is poured into another aqueous solution
> containing a metal compound (such as Iron sulfate), does the EDTA separate the
> Iron ions from the sulfate ions by binding just to the Iron ions
EDTA encloses the metal ions.
It's German website but one figure should tell more than thousand words:
http://de.wikipedia.org/wiki/Chelatkomplexe
> and the sulfate
> ions remain behind in the aqueous solution?
Yes.
> 2. Does the metallic compound that is to be sequestered by EDTA have to be in a
> solution like water that separates the compound into ions before it can be
> sequestered by EDTA?
I am not specialist for inorganic chemistry but i guess you are on right.
> Can EDTA work in an ethanol solution containing an
> organo-metallic compound if the ethanol solution does not dissolve or
> disassociates the compound into ions.
I don't think so.
> 3. Lets say that we have a trace amount (picogram) of a chemical compound on the
> surface of paper in chromatography that we need to locate. But because of its
> trace amount, its optical density precludes a color reaction that we can see
> with the naked eye. Can EDTA be used as a bridge to attach itself (bind) to the
> trace amount of chemical compound and concurrently to a larger amount of another
> chemical compound that can readily give a color reaction with a reagent. In this
> way, the trace amount of chemical compound (which is too limited in amount to
> give a color reaction that can be seen with the unaided human eye) can be
> detected and located by a color reagent reaction with the larger attached
> compound?
For some metal other reagant can be used. I remember a very sensitive
proof for Aluminum using Morin in Acetic Acid and ultraviolet light.
> In other words, can EDTA serves as a bridge or connection between the
> two different chemical compounds such that the color reaction to one compound be
> used to detect and thus locate a smaller picogram compound on a paper substrate?
To make a long story short: You want to use EDTA as a kind of intensifier?!
> Any help would be apprecaited!
Because it is a quite interesting question i do cross post to German
speaking group. It's a little bit more traffic over there - and the
chance is good that the friend try to answer in english.
--
Glï¿œck Auf - Bodo Mysliwietz
----------------------------------------
http://www.labortechniker.de/
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Bodo Mysliwietz
Apr 9, 2013, 3:26:26 PM4/9/13
to
Am 02.04.2013 21:01, schrieb Bodo Mysliwietz:
Hallo Freunde,
Hallo Freunde,
der Verfasser des Postings (John) hat leider Probleme auf newsserver
zuzugreifen (zu psoten). Mit seinem Deutsch ist es auch schlecht
bestellt. John fragte mich per eMail ob doch jemand etwas zu Punkt 3
sagen kï¿œnnte?
John geht es tatsï¿œchlich darum ob EDTA oder gar eine andere Substanz
eingesetzt werden kï¿œnnte um die Empfindlichkeit (Nachweisgrenze) zu
erhï¿œhen. Quasi nach dem Prinzip: Wir docken ein Molekï¿œl an, an das
wiederum andere Substanzen (mehrfach) gebunden werden kï¿œnnen. Der
Nachweis soll visuell erfolgen.
Fï¿œr die guten Anorganiker mit fehlenden Englischkenntnissen. Es geht um
Spuren (Picogramm) von Metallen (Eisen??) auf Papier die sichtbar
gemacht werden sollen?
Hallo Freunde,
der Verfasser des Postings (John) hat leider Probleme auf newsserver
zuzugreifen (zu psoten). Mit seinem Deutsch ist es auch schlecht
bestellt. John fragte mich per eMail ob doch jemand etwas zu Punkt 3
sagen kï¿œnnte?
John geht es tatsï¿œchlich darum ob EDTA oder gar eine andere Substanz
eingesetzt werden kï¿œnnte um die Empfindlichkeit (Nachweisgrenze) zu
erhï¿œhen. Quasi nach dem Prinzip: Wir docken ein Molekï¿œl an, an das
wiederum andere Substanzen (mehrfach) gebunden werden kï¿œnnen. Der
Nachweis soll visuell erfolgen.
Fï¿œr die guten Anorganiker mit fehlenden Englischkenntnissen. Es geht um
Spuren (Picogramm) von Metallen (Eisen??) auf Papier die sichtbar
gemacht werden sollen?
Martin
Apr 9, 2013, 11:27:05 PM4/9/13
to
Hallo Bodo,
>
> John geht es tatsächlich darum ob EDTA oder gar eine andere Substanz
> eingesetzt werden könnte um die Empfindlichkeit (Nachweisgrenze) zu
> erhöhen. Quasi nach dem Prinzip: Wir docken ein Molekül an, an das
> wiederum andere Substanzen (mehrfach) gebunden werden können. Der
> Nachweis soll visuell erfolgen.
>
> Für die guten Anorganiker mit fehlenden Englischkenntnissen. Es geht um
elementspezifisch hinkriegen (einfach Farbstoff ans entsprechende Chelat
koppeln). Mir ist aber nicht bekannt, ob es schon jemand gemacht hat.
Aber ich bin ja nicht nur kein Anorganiker, sondern auch schon seit Jahre
aus der Materie raus...
Tschüs,
Martin
>
> John geht es tatsächlich darum ob EDTA oder gar eine andere Substanz
> eingesetzt werden könnte um die Empfindlichkeit (Nachweisgrenze) zu
> erhöhen. Quasi nach dem Prinzip: Wir docken ein Molekül an, an das
> wiederum andere Substanzen (mehrfach) gebunden werden können. Der
> Nachweis soll visuell erfolgen.
>
> Für die guten Anorganiker mit fehlenden Englischkenntnissen. Es geht um
> Spuren (Picogramm) von Metallen (Eisen??) auf Papier die sichtbar
> gemacht werden sollen?
Könnte - sicherlich. Mit einiger Sicherheit könnte man das sogar
> gemacht werden sollen?
elementspezifisch hinkriegen (einfach Farbstoff ans entsprechende Chelat
koppeln). Mir ist aber nicht bekannt, ob es schon jemand gemacht hat.
Aber ich bin ja nicht nur kein Anorganiker, sondern auch schon seit Jahre
aus der Materie raus...
Tschüs,
Martin
Patrick Kibies
Apr 10, 2013, 6:59:22 AM4/10/13
to
Hi JD,
Bodo posted, that you're still looking for an answer. So I'll try my very
best. But I'm neither an inorganic chemistrian nor an expert for trace
analysis of heavy metals. But let's give it a bash.
JD wrote:
> 3. Lets say that we have a trace amount (picogram) of a chemical compound
> on the surface of paper in chromatography that we need to locate. But
> because of its trace amount, its optical density precludes a color
> reaction that we can see with the naked eye.
The fiest question is: Why do you want to do it with the naked eye. I just
imagine some fluorescent marker, which could just be visualized by
illumination with UV-Ligt. I don't know if there are any chelating agents,
which are fluorescent. The main Problem I see, is that chelation would
increase solubility of your compound dramatically - it just would dissolve
or dislocate.
> Can EDTA be used as a bridge
> to attach itself (bind) to the trace amount of chemical compound and
> concurrently to a larger amount of another chemical compound that can
> readily give a color reaction with a reagent.
I think there are chelating ligands, which can do such stuff. But I'm not an
organic chemist.
> In this way, the trace
> amount of chemical compound (which is too limited in amount to give a
> color reaction that can be seen with the unaided human eye) can be
> detected and located by a color reagent reaction with the larger attached
> compound? In other words, can EDTA serves as a bridge or connection
Why do you need it on the paper? Maybe there is an easier way to do your
job...
regards
Patrick
Bodo posted, that you're still looking for an answer. So I'll try my very
best. But I'm neither an inorganic chemistrian nor an expert for trace
analysis of heavy metals. But let's give it a bash.
JD wrote:
> 3. Lets say that we have a trace amount (picogram) of a chemical compound
> on the surface of paper in chromatography that we need to locate. But
> because of its trace amount, its optical density precludes a color
> reaction that we can see with the naked eye.
imagine some fluorescent marker, which could just be visualized by
illumination with UV-Ligt. I don't know if there are any chelating agents,
which are fluorescent. The main Problem I see, is that chelation would
increase solubility of your compound dramatically - it just would dissolve
or dislocate.
> Can EDTA be used as a bridge
> to attach itself (bind) to the trace amount of chemical compound and
> concurrently to a larger amount of another chemical compound that can
> readily give a color reaction with a reagent.
organic chemist.
> In this way, the trace
> amount of chemical compound (which is too limited in amount to give a
> color reaction that can be seen with the unaided human eye) can be
> detected and located by a color reagent reaction with the larger attached
> between the two different chemical compounds such that the color reaction
> to one compound be used to detect and thus locate a smaller picogram
> compound on a paper substrate?
As mentioned above: I fear chelation will remove your stuff from the paper.
> to one compound be used to detect and thus locate a smaller picogram
> compound on a paper substrate?
Why do you need it on the paper? Maybe there is an easier way to do your
job...
regards
Patrick
gUnther nanon�m
Apr 10, 2013, 12:44:10 PM4/10/13
to
"Bodo Mysliwietz" <druidef...@gmx.de> schrieb im Newsbeitrag
news:asj8ao...@mid.individual.net...
> F�r die guten Anorganiker mit fehlenden Englischkenntnissen. Es geht um
> Spuren (Picogramm) von Metallen (Eisen??) auf Papier die sichtbar gemacht
> werden sollen?
Hi,
> werden sollen?
beim n�chsten Forensiker etwas Luminol abstauben?
--
mfg,
gUnther
Bodo Mysliwietz
Apr 14, 2013, 7:07:07 AM4/14/13
to
Am 10.04.2013 18:44, schrieb gUnther nanonï¿œm:
> "Bodo Mysliwietz" <druidef...@gmx.de> schrieb im Newsbeitrag
> news:asj8ao...@mid.individual.net...
>
>> Fï¿œr die guten Anorganiker mit fehlenden Englischkenntnissen. Es geht um
> "Bodo Mysliwietz" <druidef...@gmx.de> schrieb im Newsbeitrag
> news:asj8ao...@mid.individual.net...
>
>> Spuren (Picogramm) von Metallen (Eisen??) auf Papier die sichtbar gemacht
>> werden sollen?
>
> Hi,
> beim nï¿œchsten Forensiker etwas Luminol abstauben?
>> werden sollen?
>
> Hi,
Keine Ahnung ob es geht. Zumindest stellt es eine Option zur Recherche
an, die allerdings nicht viel mit EDTA zu tun hat, was vermutlich auch
nicht fï¿œr John zwingend ist.
@John: Depending on your application it was recommended to check once
for the catalytic oxidation of Luminol (CAS 521-31-3) forced by trace of
Iron (or Cupper) as done by forensic experts.
Please refer to:
http://en.wikipedia.org/wiki/Luminol
as well....
http://freepaulcortez.org/wp-content/uploads/2011/12/increasing_the_specificty_of_the_forensic_test_for_blood.pdf
HTH
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