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Author: Subject: Dimethylglyoxime
NEMO-Chemistry
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[*] posted on 13-6-2018 at 11:33
Dimethylglyoxime


I have read wikipedia etc, it all mentions using it for the detection of
Nickel.

What it dosnt tell me is how much of the powder to use in solution...
I have 5g which was pretty expensive, as i am doing things with Nickel chemistry i thought it would allow me to quantify the amount of nickel, now i could just 'mix' some with DI water and use that.


I understand that if i was to use it to titrate then i simply take its molecular weight (116.2/mol) and make a X mm solution.

But how much would you use in say 200ml of DI water to keep as a stock solution to just detect the presence of Nickel?

[Edited on 13-6-2018 by NEMO-Chemistry]
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Aqua-regia
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[*] posted on 13-6-2018 at 12:02


DMG is mainly uses in 1% ethanolic solution. Not soluble in water. If you have a solution containing Ni, buffering it to pH 8, and add a few ml 1% DMG alcoholic solution. It is forming a raspberry red precipitat.

A typical gravimetric estimation of the nickel, byside iron and copper:

If you have 0,13-0,17 g dissolved nickel ions in the beaker, complexise the other metallic ions with 20 ml 20% tartaric acid solution, heat the soln carefully till 40-45 degrees, add 15 ml 20% Na2S2O3 soln, buffering with HCL pH 4-4,5. Few minits later add into the beaker 65 ml 1% ethanolic DMG soln. Puffering pH than pH 8-8,5 with NH3 soln, keep it in 45 degrees a half an hour, the Ni-DMG will 100% precipitated, you can filtering with G3 fritted filter, washing twice with 10 ml water. Drying at 120 degrees 2 hours.



[Edited on 13-6-2018 by Aqua-regia]
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[*] posted on 13-6-2018 at 14:53


Quote: Originally posted by Aqua-regia  
DMG is mainly uses in 1% ethanolic solution. Not soluble in water. If you have a solution containing Ni, buffering it to pH 8, and add a few ml 1% DMG alcoholic solution. It is forming a raspberry red precipitat.

A typical gravimetric estimation of the nickel, byside iron and copper:

If you have 0,13-0,17 g dissolved nickel ions in the beaker, complexise the other metallic ions with 20 ml 20% tartaric acid solution, heat the soln carefully till 40-45 degrees, add 15 ml 20% Na2S2O3 soln, buffering with HCL pH 4-4,5. Few minits later add into the beaker 65 ml 1% ethanolic DMG soln. Puffering pH than pH 8-8,5 with NH3 soln, keep it in 45 degrees a half an hour, the Ni-DMG will 100% precipitated, you can filtering with G3 fritted filter, washing twice with 10 ml water. Drying at 120 degrees 2 hours.



[Edited on 13-6-2018 by Aqua-regia]


Thank you for the info, that will teach me to make assumptions on water solubility!! Silly mistake on my part. The information you have given is most helpful.

Looks like a unusual colour for a Nickel complex, nice raspberry red. Out of interest do you have any idea if Methanol can be usd instead of ethanol for a 'quick n dirty' Nickel test?
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[*] posted on 13-6-2018 at 18:15


DMG is not a terribly difficult synthesis. I have run this prep before. It works as advertised: http://www.orgsyn.org/Content/pdfs/procedures/CV2P0204.pdf
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[*] posted on 13-6-2018 at 18:21


Methanol should be fine.



Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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[*] posted on 14-6-2018 at 01:55


Quote: Originally posted by DraconicAcid  
Methanol should be fine.


thats good i got plenty of that.

i will look the prep up as it isnt cheap to buy
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[*] posted on 14-6-2018 at 02:33


If you are teacher use rectified spirit instead meOH. Toxicology!!!
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[*] posted on 14-6-2018 at 03:45


Quote: Originally posted by Aqua-regia  
If you are teacher use rectified spirit instead meOH. Toxicology!!!


lol.


(I have worked with 45 gallon barrels of the stuff, been arms deep in it, short of drinking it, or standing in a tiny tiny room with massive amounts evaporating you'd be very hard pressed to be poisoned by it.

So I can say with out a doubt working with tiny amounts we're talking of here it is delusional to be even concerned about it. Other guys washed their hands with it, washed out cuts *Now that I'd agree bad idea!*)

But this just shows how modern day hysteria is effecting the newer generations

It is good to be mind full of its properties, but one must all so realize reality, a kid would be more likely to chance drinking it if he knows it is "grain alcohol" then if he knows it is a poison, and only so much so IF you drink it!

(Given usage in this context you won't be bathing in it nor inhaling large amounts)
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[*] posted on 14-6-2018 at 05:34


"But this just shows how modern day hysteria is effecting the newer generations"

This is just a question about the taking of risk and responsibility of teacher nothing else. Iam personally not belong the new generation , but I had been a witness a lab poisoning with meOH. The guy got blindness. He mixed an alcoholic coctail in the lab, but used meOH....
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