PowerShell LADR error correlation workaround

This PowerShell function is made to assist the user in changing specific mass header values in Agilent 8900X QQQ mass spectrometer output CSV files for the purpose of enabling ratio error correlation calculation and output from LADR for non U-Pb geochronometry. The edited data files should ONLY be used to generate error correlations.

It is a cross-platform function that requires minimal user input via two defined parameters folderpath and decaysystem. The function has no restrictions on the number of files, and performs the replace operations in parallel to reduce runtime.

Operational features of the function

• Parameter validation prior to function run
• Creates two new directories in the user defined folderpath: 'Originals' and a decaysystem_to_UPb (either "RbSr_norm_to_UPb", "RbSr_inv_to_UPb", "RbSr88_norm_to_UPb", "RbSr88_inv_to_UPb", "LuHf_norm_to_UPb" or "LuHf_inv_to_UPb" depending on the user defined decaysystem)
• Moves all original, unedited CSV files to the 'Originals' folder
• Copies all CSV files in 'Originals' to decaysystem folder
• Runs replace operation on CSV files in decaysystem folder to change:

• Rb85 or Lu175 to U238
• Sr87 or Hf176 to Pb207 (normal isochron) or Pb206 (inverse isochron)
• Sr86 or Sr88 or Hf178 to Pb206 (normal isochron) or Pb207 (inverse isochron)
• U238, U235, Pb207, & Pb206 to U234, U232, Pb205, & Pb202 (to offset from these isotopes if measured)

Adding the function to PowerShell

Firstly, ensure the cross-platform PowerShell Core V7 or higher is installed. See Get PowerShell for detailed instructions. It can be installed via most OS package managers (e.g., winget, homebrew, apt).

To obtain this PowerShell function, either clone the repository if you are familiar with Git, OR create a new file in a program like Visual Studio Code, Notepad, TextEdit etc called LADRWorkaround.ps1 and copy the entire code from LADRWorkaround.ps1 into the file then save it. Place the ps1 file into a stable location (I recommend using Git for this reason and for if I update the code, fix bugs etc.), just place it somewhere you are not likely to accidentally delete it. GitHub desktop is an easy way to enter the world of Git without having to use a CLI.

You can either Import-Module Path/LADRWorkaround.ps1 for each session that you need to use it, or to save some time in future I recommend setting up a PowerShell profile if you haven't already. To import the function on a session basis, for each session first run (where SomeDirectory is the path where the ps1 file is saved):

Import-Module 'SomeDirectory\LADRWorkaround.ps1'

To 'permanently' load the function so you do not have to run the previous code each session, first check for a profile file and create one if none exists using the following code:

if (!(Test-Path -Path $PROFILE )) { New-Item -Type File -Path $PROFILE -Force }

Then open the profile in a text editor using (below example is for MS Windows, replace notepad with the appropriate program on Linux & Mac):

notepad $PROFILE

Add the filepath to the LADRWorkaround.ps1 to the profile file that is open in notepad and prefix it with Import-Module (change the \ to / for Linux & Mac):

Import-Module 'SomeDirectory\LADRWorkaround.ps1'

Save the profile file and close your text editor. Now whenever you open the PowerShell terminal it will import the function by default so you can immediately call the function using Edit-LADRWorkaround and you do not need to explicitly run Import-Module each session.

Using the function

Operation of the function itself is simple, users need to specify a -folderpath and -decaysystem. To call the function the user needs to type

Edit-LADRWorkaround

in the PowerShell terminal followed by

-folderpath 'string' 

and

-decaysystem 'string'

where -folderpath needs to be provided as a quote bound string of a path, and -decaysystem a quote bound string of value 'RbSrNorm', 'RbSrInv', 'RbSr88Norm', 'RbSr88Inv', 'LuHfNorm' or 'LuHfInv'. Your final line of code to run should look similar to:

Edit-LADRWorkaround -folderpath 'C:\Users\UserA\SomeData' -decaysystem 'RbSrNorm'

If it does, press the return (enter) key to run the function.

If a parameter is incorrectly set, PowerShell will notify you and ask you to set it. If it is incorrectly set again the function will terminate.

Basic help is available in the function and can be accessed by:

help Edit-LADRWorkaround

If you've followed these instructions you should be able to quickly process as many files as you need with ease.