Sample Prep: Addition of Acidic Exchangers?

[jelwell]

Hi All! I am working on a method to identify MEK and 2,3 Butanediol in solution, and found a method that mimics the analysis we want done, but I have one question... They mention:

"Before injecting a 20 μl reactor sample into the column, the solution is spiked with acidic exchangers (Amberlite IR-120H+). This prevents the contamination of the column with heavy metal ions."

I have never done this type of analysis before, and do not know how much "spiked" indicates? What is the appropriate amount/ratio to add? I can't seem to find any additional information on this method, but I definitely want to heed their advice as it is possible heavy metal will come from the catalyst we are using in our reaction.

I greatly appreciate any help with this!

[christophe_j]

i will make sure the Amberlite IR-120H+ is in excess (enough in and a bit more) all this will do is make sure any amounts of heavy metals are mopped up before they hit the column.
i dont think to much is going to cause a big problem.
Regards
Christophe

[jelwell]

Thanks for the reply, Christophe. What does "in excess" mean amount-wise? What ratio am I looking at? Is this then filtered out when I filter the sample?

Thanks again for your help!!

[ScottHorn]

I don't know about the ion exchanger mentioned (Amberlite), but I know that some that I've used in the past indicate that they are fully "loaded" with a color change. For example a preparative ion exchange method I used a while back required a deionized urea solution. I used a mixed bed ion exchanger that consisted of blue and orange beads. When the beads had adsorbed their maximum capacity of ions they became clear. This made it easy to know when you needed to add more. I think the method suggested starting with something like 1 g per 100 ml of solution, but YMMV.

[jelwell]

Interesting. I will call Sigma and see what I can learn about this.

Thanks for the input!