7900: What's causing my standards to split?

Are you running the full Start Up (Torch Axis, EM, Plasma Correction, Resolution/Axis, Standard Lens Tune, and Performance report)? You mentioned running an autotune, but it's also important to run the Start Up which optimizes hardware settings that the batch autotune does not. The batch autotune only optimizes the lenses for each tune mode. 

Also, typically we run the HMI-4 preset for most EPA sample matrices, this will have preset parameters for the RF Power, Sample Depth, Nebulizer and Dilution Gas Flows. The preset conditions are well vetted to provide the most robust conditions, so I recommend reverting back then reevaluating the drift issue. I would uncheck the box for all parameters and go back to the preset mode for HMI since right now you are running an odd mix of low matrix and HMI which will not yield the best stability. 

Also, how old are your cones?

What concentration internal standard are you using?

Can you confirm that your grounding T (also called the mixing T) is clamped in the peri pump?

Are you running the mineral elements as well (Ca, Na, Fe, K, etc)?

Chelsea Tajc said:

Also, typically we run the HMI-4 preset for most EPA sample matrices, this will have preset parameters for the RF Power, Sample Depth, Nebulizer and Dilution Gas Flows. The preset conditions are well vetted to provide the most robust conditions, so I recommend reverting back then reevaluating the drift issue. I would uncheck the box for all parameters and go back to the preset mode for HMI since right now you are running an odd mix of low matrix and HMI which will not yield the best stability. 

Update on this: My tune counts have dramatically decreased. I'm getting 1/4 of what I used to. It's making it very difficult to pass a He tune due to poor RSD

If your cones are only a week old I would not clean them, cones run best when they are a little dirty or “conditioned” and I only clean them if my performance report indicates the orifice might be clogged. I always like to condition cones with the ICSA or 0.3% NaCl for at least 30 min 

Often upward drift is indicative the cones are not the issue. I would have to see more of the data to know exactly what’s occurring since this is tricky to troubleshoot without seeing in person, how are the RSDs for H2 mode esp the ISTDs? Are they going up on samples or for QC?

Feel free to compress any of your data batches (entire .b file) and send to me. My email: chelsea.tajc@agilent.com. Please add in the subject line “Agilent Community” 

"I always like to condition cones with the ICSA or 0.3% NaCl for at least 30 min"

I only do 15 mins, I wonder if it's just not long enough. All the literature said 10. 

Chelsea Tajc said:

ow are the RSDs for H2 mode esp the ISTDs? Are they going up on samples or for QC?

The RSDs look pretty solid. Between 0 and 5%, there's a few outliers but it looks random. A CCB at 10% and a sample at 8%

Feel free to send me your batch or method. I’m happy to look it over and offer more advice. Often these issues are hard to troubleshoot in the forum and in email I will be able to share larger files. I left my email above on one of the replies. 

What is  ICSA?

ICSA is an interference check solution used for EPA methods. It’s a mix of elements (primarily minerals) at high levels which is why we use it for cone conditioning. 

ICSA is an interference check solution used for EPA methods. It’s a mix of elements (primarily minerals) at high levels which is why we use it for cone conditioning. 

Thank you for explaining!