interfering species in the determination of Ni using DMG

[tsangchuiyi]

Hi guys,

What metal ions are the interfering species in the determination of nickel using the dimethylglyoxime method. Suggest a solution to this problem.


I know the interfering species inculde Fe2+, Co2+, Cu2+. Are there anymore?
Actually I don't know the reason why Fe2+, Co2+, Cu2+ are interfering species. Can somebody explain to me?
Please suggest a solution to this problem.

Thanks.
TCY

 

[Lino1406]

To get copper and cobalt out is easy. Copper in this environment
is either black or blue, what interferes.

 

[tsangchuiyi]

To get copper and cobalt out is easy. Copper in this environment
is either black or blue, what interferes.

So how can I get out Cu? My sample is Ni-Cu alloy.

 

[FrugalRefiner]

So how can I get out Cu? My sample is Ni-Cu alloy.

You shouldn't need to worry about the copper. When I mixed my first batch of DMG, I tested it on some filings from a U.S. five cent coin known as a nickel. The alloy used to make these coins is 75% copper and 25% nickel. The DMG worked just fine, turning the classic pink color. Actually, if you look very close, you'll see tiny specks of red, which, from a little farther away present a pink color. I wouldn't think the copper would be an issue if you're just trying to detect the presence of nickel.

Dave

 

[goldsilverpro]

Hi guys,

What metal ions are the interfering species in the determination of nickel using the dimethylglyoxime method. Suggest a solution to this problem.


I know the interfering species inculde Fe2+, Co2+, Cu2+. Are there anymore?
Actually I don't know the reason why Fe2+, Co2+, Cu2+ are interfering species. Can somebody explain to me?
Please suggest a solution to this problem.

Thanks.
TCY

Where did you read that Fe2, Co2, Cu2 are interfering ions? What I read was that the only strongly interfering ions are auric, cobaltous, and dichromate. Au+++, Co++, and Cr2O7-- These can interfere because of their intense colors.

 

[tsangchuiyi]

So how can I get out Cu? My sample is Ni-Cu alloy.

You shouldn't need to worry about the copper. When I mixed my first batch of DMG, I tested it on some filings from a U.S. five cent coin known as a nickel. The alloy used to make these coins is 75% copper and 25% nickel. The DMG worked just fine, turning the classic pink color. Actually, if you look very close, you'll see tiny specks of red, which, from a little farther away present a pink color. I wouldn't think the copper would be an issue if you're just trying to detect the presence of nickel.

Dave

My sample is Ni-Cu alloy and the interfering species should be Cu2+. So how can I remove Cu2+ to ensure that dimethylglyoxime ligand will react with Ni2+ only?

TCY

 

[goldsilverpro]

Have you tried dissolving a little and testing it as is? The only reason Cu++ might be a problem is because it is an intense blue when made ammoniacal. Dilution might help.

 

[Lino1406]

Cu will dissolve in concentrated nitric acid while nickel and iron are passivated. Co dissolves in
any acid, although it may take time

 

[goldsilverpro]

Cu will dissolve in nitric acid while nickel and iron are passivated. Co dissolves in
any acid, although it may take time

With a Cu/Ni alloy, once the copper is nearly gone, the nickel will start dissolving in hot 50/50, or a bit weaker, nitric. Nickel will also slowly dissolve in hot 37% HCl.

 

[FrugalRefiner]

Cu will dissolve in nitric acid while nickel and iron are passivated. Co dissolves in
any acid, although it may take time

With a Cu/Ni alloy, once the copper is nearly gone, the nickel will start dissolving in hot 50/50, or a bit weaker, nitric. Nickel will also slowly dissolve in hot 37% HCl.

If it's very finely divided, it will dissolve even without heat. I filed the edge of a nickel for my DMG test. I added the filings, a few drops of distilled water and a few drops of nitric to a white plastic spoon. I checked on it a couple hours later and everything was dissolved. I added several drops of ammonia and a couple of DMG and got a very pretty pink.

Dave