Creating a reference solution from ICP-EOS

Charles Silva · Apr 8, 2017

Hi all

I would like to know if before sending the vials to ICP-EOS can I store a volume like a liter to be used in the future as a reference solution for my Ca, Mg, KH, K aquarium kit tests.
For how long can I use this reference solution or are there reactions that could mask the "absolute" values ?

Rob Lion · Apr 8, 2017

even in an full air tight container, over time reactions will take place due to temp changes, precipitations and bacteria i think.

When i did my ICP, I did a full test on everything i could before sending the sample vials off from the same water samples.

JimWelsh · Apr 9, 2017

ICP doesn't measure KH, but for the major elements, such as Ca, Mg, & K, as long as you guarded against evaporation, I would expect you to be able to store an aliquot for months, if kept at a reasonable temperature. For trace elements, that's probably a different story.

Randy Holmes-Farley · Apr 9, 2017

The normal procedure for such samples is to acidify it strongly to prevent any preciptiation, but when a reviewer sent an acidified sample to Triton they complained that it wasn't safe as they expect it is seawater, and might not give the exact same answer since the matrix has changed. I'm not sure how valid either point really is.