[tomitmy]

Hi everyone
I have a bit of a problem, i need to make a digestion of a sample and i found a paper that uses a microwave for digestion. it states the following : Digestion conditions for the microwave system were applied as 2 min for
250 W, 2 min for 0 W, 6 min for 250 W, 5 min for 400 W, 8 min for 550 W and vent 8 min.
I have only worked with temperature ramps, how can i translate this into temperature?

Best Regards

[Corribus]

Not a great way to report a digestion procedure. Usually temperature and hold times, as well as venting pressures, are reported. Depending on your microwave you might be able to just input heating powers (I'd have to check to see if I can put a method in like that) but I still don't think it's necessarily transferable from one system to another, because vessel designs and materials differ.

What are you trying to digest and what's your end application? If it's ICP-MS, the good thing is that all you're really usually looking for is a homogeneous solution, and there isn't necessarily one way to get that. A lot of microwaves come programmed with good methodological starting points for a variety of matrices. And if you get stuck, I've found that the manufactures usually are good about helping you digest a troublesome matrix. If it's a CEM or Milestone or something, just give the application engineers a call, and I'm sure they'd be able to help you out.

[tomitmy]

Thank you so much for your help and answer.
In fact is for ICP-OES, and its a molasses sample. unfortunately the microwave doesnt have a preloaded program for this sample. and in my country there are on application engineers. anyhow thanks so much for your help

Best
E

[Corribus]

Molasses is largely carbohydrate, which should be fairly easily digestible. Does the microwave have any preloaded programs for food samples. You may even try one for an organic polymer or other organic matrix as a starting point. Probably nitric acid, maybe 225-250 C, 10 minutes, stepwise venting, or something like that. A little trial and error and I bet you can get this digested without too much trouble. Just make sure to keep the sample size small in the beginning - organic matrices produce a lot of gas during digestion and you can easily burst a vessel. We try to keep our sample sizes or organic polymers under 200 mg typically, even though the vessels are rated I think to 0.5 g.