DMG testing solution

[Oz]

I got my DMG in today and in looking for direction in mixing up a testing solution found;

Lazesteve suggests adding ¼ gram DMG in 25ml of ethanol

Ammend states “Dissolve one gram of DMG by bringing it to a boil in 100cc of distilled water (about four fluid ounces). Let this stand overnight, then filter it to remove any crystals or sediment.

Hoke uses water as well.

What are the advantages or disadvantages to using ethanol vs. water for this?

 

[Lou]

Ethanol will work fine. You get a more stable solution with ethanol as it is more soluble than in water.

 

[goldsilverpro]

The water solution is supposed to be more sensitive but the alcohol solution is easier to make. I usually used the water solution if I didn't need it immediately. In both cases, they are 1% w/v solutions.

 

[Oz]

Thanks for the super fast replies! I had noticed that all 3 used 1% w/v solutions but was curious as to what advantage Steve gained by using ethanol. Do either of you know of cases where one would not want the addition of alcohol? I have read of ethanol being used a precipitate in some cases but don’t remember with what off the top of my head. I’m just trying to think ahead as to the potential of a co-precipitation in some cases.

Thanks again!

 

[goldsilverpro]

I was mistaken. It wasn't the sensitivity. Here's a quote from a post I made about a year ago:

"I read somewhere that the 1% DMG distilled water solution works faster and more efficiently than the alcohol solution. I know, from experience, that the DMG will finally dissolve in water. Takes a little heat, time, and shaking or stirring."

Harold also used a distilled water solution.

 

[Lou]

Ethanol will not reduce to metal any palladium salts that we will be dealing with in the context of this forum. Ethanol is occasionally used as a precipitant for other PGMs like rhodium and ruthenium. I dislike the use of ethanol as it produces a fine, almost un-filterable product.

Since you are using this solution to qualitatively test for Pd, and also nickel, concentration of the solution used to test is not terribly important. If, however, you wanted to know how much Pd was in solution, then it would be important. There is no real advantage to using ethanol save in solubility. Classically, for nickel determination it is used in ethanol.


All the DMG I've ever used does not dissolve in cold water at least to any appreciable degree, even by the nickel test. The water must be hot. I suggest a volumetric flask and freshly boiled distilled water.

 

[Oz]

It was just such cases as Rh and Ru you referred to that I was curious about. Although I do not expect to be testing many solutions that contain Ru, the Rh is a consideration in some. It seems that it may be worth while to use water if it is not too great a problem getting it into solution.

I had not thought about it before, but you bringing it up I would be interested in how you would use DMG for a quantitative result of palladium.

 

[Lino1406]

Is 1/0.35 (about 3) the Pd weight