Cd analysis using 8900 QQQ

Sensitivity for cadmium in O2 (on mass 111/111) is 60% compared with no gas mode. Cadmium did not react with O2 so in mass shift (111/127) sensitivity is 0.5%. 

In O2 mode some problems with interferences are eliminated, so if sensitivity is not a problem you can use O2 mode or both O2 and no gas.

Thanks for your reply. It is much appreciated. I totally understand your explanation. 0.5% sensitivity is not much isn't... I don't think I can make it as I have pretty low concentrations. But, since the Cd with O2 (no mass shift) is better that the He mode, is it legitimate to use it since I did not ran it in no gas mode and since the results are better (my QCs as well as CRMs) than He mode?

Thanks,

Thanks for your reply. It is much appreciated. I totally understand your explanation. 0.5% sensitivity is not much isn't... I don't think I can make it as I have pretty low concentrations. But, since the Cd with O2 (no mass shift) is better that the He mode, is it legitimate to use it since I did not ran it in no gas mode and since the results are better (my QCs as well as CRMs) than He mode?

Thanks,

I don't know what is sensitivity in He mode, probably it's the same like in O2 mode. I use He mode for polyatomic ions ( masses between 40-90) so there no need of He for Cd 111. But if you use only He mode, you can use it also for cadmium. If more sensitivity is needed you must add no gas mode. If there some interferences you can use O2 mode. I regularly use O2 mode for arsenic, so it's no problem to add one more element (Cd). 

Hi again,

I get that. But in this particular case, I did not ran Cd in no gas mode. I have He and O2 (no mass shift). The recoveries for my QCs within the run are way better in O2 mode (no mass shift) even if no reaction between O2 and Cd happen. Would those be valid? I would think it will, but need a second opinion. Thanks!

Yes, better RSD is because In MS/MS mode, the oxygen introduced into the collision reaction cell can be reacted with ¹¹¹Zr¹⁶O¹H⁺, ¹¹¹Mo¹⁶O⁺, inducing electron transfer, dehydrogenation, oxygenation and other reactions that inhibit the overlapping interference of these polyatomic ions on ¹¹¹Cd.