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FAAS problem with cadmium analysis

Posted: Mon Oct 30, 2017 12:00 pm
by control
Hello,

I have a Varian Spectra 55B and i've been analyzing cadmium in water samples, most of the samples are negative for cadmium but there are a few that give me false positive, i'd sent the samples to another laboratory and analyze with ICP and the samples are negative. I was thinking that the problem is in the flame but im not sure...i'd tried the interferences that says in EPA method, tried with KCl solution, filtration,reduce the width of opening window...but all went wrong...what can i do?

Re: FAAS problem with cadmium analysis

Posted: Mon Oct 30, 2017 12:16 pm
by dblux_
control wrote:
...what can i do?

Perhaps find a forum devoted to AAS :-)

Re: FAAS problem with cadmium analysis

Posted: Mon Oct 30, 2017 2:12 pm
by control
i know this is a chromatography forum but i read some posts about AAS, i didnt find an AAS forum, do you know one?

Re: FAAS problem with cadmium analysis

Posted: Mon Oct 30, 2017 2:53 pm
by dblux_
Unfortunately no.

Re: FAAS problem with cadmium analysis

Posted: Mon Oct 30, 2017 5:52 pm
by uzman
The standard wavelenght is 228.8 nm for cadmium , but did you try also the wavelenght 326.1 nm ( which is less sensitive ) ?

The flame must be oxidizing ( blue ) and a slit width 0.7 nm recommended.

What are the standard concentrations ?