'INF' values for LOD

woje

Hi everyone. For some reason, I keep getting 'inf' in some places instead of actual limits of detection. How do I get around this?

Bence

Hi @woje

Inf LOD means that you have zero sensitivity (using the equation from Longerich et al, discussed here).

You should check the count rate for your internal std and element of interest for those selections. They are likely at the same level as baselines. You may get lower baselines by adjusting your baseline selections.

Kind regards,
Bence

woje

Bence Hi Bence, I have adjusted my baselines, but it has had no effect so far. Is there anything else I can do?

Joe

woje

Which LOD calculation are you using? If Pettke, perhaps the dwell times have not been set? Some instruments include this data and we import it automatically, others need to be specified via the Tools -> Dwell Times menu item.

woje

Joe I am using the Longerich LOD's.

woje

woje I have emailed my Iolite files to your support email address; if you could please take a look and give me any recommendations. Thank you.

Joe

woje

For anyone that ends up in this thread: the problem here was that the background subtracted RM spline was dipping below zero. One way to fix it in this case would be to change the spline type.