3D Trace Elements - Calibration/Quantification of Ratios?

DAF

Moin

I'm trying to implement the 3D Trace Elements DRS to quantify element ratios - using a ratio calibration approach. Although the DRS calculates the ratios - it calculates somehow the results in 'ppm' and thus multiplies the ratios by 10⁶. Is there an option to avoid scaling to ppm - or adding an option to use the DRS for ratios?

I have calculated using the 'Channels' - 'Calculator' tool a new Input Channel, manually added the property regarding which "Element" the Input Channel is, so the DRS finds the ratio in the reference materials. In the reference materials the Element Ratios are defined as 'ratios', however after reloading they are 'empty'. Using python code, I can access the ratio and make calculations without any problems.

Best regards,
Daniel

Bence

Hi Daniel,

Sorry for the delayed response to your post (we have been changing the forum in the past couple of weeks).

Ratios in the Reference Materials browser have no units and show it appears empty. That's OK and doesn't affect anything (as you've found via the python interface).

Are you trying to calculate the ppm values and then create ratio channels? Or are you trying to avoid the ppm calculation and just calculate RM-normalised ratios?

Kind regards,
Bence

DAF

Hi Bence
No worries.

I'm not interested (for this use case) in the elemental concentrations, just the ratios. Thus I want to calibrate and quantify ratios directly.

Best regard,
Daniel

Bence

Hi Daniel,

Do you need the 3D calibration surfaces (i.e. are you using multiple reference materials)?

If not, a simple custom DRS could do this for you.

Kind regards,
Bence

DAF

Hi Bence
I use multiple reference materials, hence the 3D DRS.
I started writing a custom DRS first, for a single ref material that works well, but realised that having multiple reference materials are beneficial for my tasks, that however excels my (basic) knowledge of python to succeed in wirting the DRS. If there is no easy fix, I'll continue to post process the data and divide it by 100'000.

best regards,
Daniel

Bence

Hi Daniel,

I think the amount of effort required to write a similar DRS to 3D Trace Elements would not be worth it, considering the possibility of mistakes etc.

Another alternative would be to set up a Calculator routine that creates new Output channels that just divides the output by 100,000. You can save Calculator setups so that you don't have to type them in again each time, and these output channels would be exported along with the other Output channels.

Kind regards,
Bence

DAF

Dear Bence,
That is a good suggestion with the calculator routine! Thanks!
best regards,
Daniel

LuisK

Hello,

I have a similar question and wanted to try to use several reference materials for isotope ratio data. I calculated new input channels with the same channel name as the ratio in my RefMat files but when trying to use the 3d trace element DRS I am not sure how to obtain corrected ratios as I do not have an internal standard.

Is there any way to do this using the DRS as you said writing a new one for a specific approach would take too much time.

Best regards,
Luis

Bence

Hi Luis,

It depends on what you want to do in your DRS and whether you could use parts of the 3D Trace Elements DRS (it's become a bit of a behemoth, and could probably be broken into modules etc).

Do you want/need to group your RM analyses into blocks and work out a correction factor for each block, and then interpolate that correction factor between blocks? Depending on the correction factor and subsequent calculations that might not be too much work. If you still want to use sum normalisation, criteria etc, then that would be quite a bit of work.

It's all open source too btw. You can see the 3DTE code on our github repo: https://github.com/iolite-LA-ICP-MS/iolite4-python-examples/tree/master/drs

Also, it customary in iolite to not overwrite input channels. Doing so means that you need to re-import you data each time you want to re-run your DRS.

Kind regards,
Bence