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Carbonates on Psi

Psi Method

Weigh your samples

  1. Find clean vials and a tray - in drawer under polly prepline
  2. Find the Psi standards - desiccator
  3. Clumped - Ideally you will have one complete set of standards analyzed each day (8 standards in total - ETH1, ETH2, ETH3, ETH4, IAEAC1, IAEAC2, Merck, GU1). Mix them up and randomize their order. This is two sets of standards per tray of 50 vials.
  4. Bulk - use ETH4, Coral, and IAEAC1
  5. Clumped - Weigh 500 µg (± 10 µg) of pure carbonate when you have very little material for analysis (cold finger mode). Otherwise, we 4.0 to 5.0 mg (bellows mode).
  6. Bulk - Weigh 50 µg (± 10 µg)
  7. Clumped - We would love to be able to declare that you need to run at least two equilibrated gases but Nu has yet to deliver a functional multiport and tube cracker (2024-10-21).

Go Start Psi

  1. Check if the previous run has finished or if Psi has crashed
  2. Pull lines out of liquid nitrogen dewar and drape off of the floor
  3. run reset everything - Analysis > Sequence > Edit > psi_reset_everything.seq, the click Run
  4. if Psi Crashed, evacuate and bake traps - Analysis > Sequence > Edit > psi_bake_all_traps.seq, the click Run
  5. thaw and dry out liquid nitrogen lines - Analysis > Sequence > Edit > psi_dry_out_liquid_nitrogen_lines.seq, the click Run
  6. Create a batch file:
    • Open C:/Nu Stable/Batches/_Clumped_Batch_Template_ColdFinger.TXT or C:/Nu Stable/Batches/_Clumped_Batch_Template_Bellows.TXT
    • save as with today's date and descriptive name (yymmdd_YourProject.txt) into the same directory the template was in
    • enter sample and standard information into batch file template and save
    • TYPE THE STANDARDS IN EXACTLY AS TYPED ABOVE
    • Enter each replicate of a given sample identically throughout your session and between sessions if appropriate. For example, "sample_1" should be entered as "sample_1" every time it is analyzed. Do not enter "sample_1_rep1", "sample_1_rep2", etc. You will be able to differentiate individual replicates using a unique identifier provided by the instrument as well as the date and time of analysis. The purpose of entering all replicates identically is to leverage Daeron's (2021) error propagation python code called D47crunch, which we employ.
    • Some prefer to use a text editor while others prefer to use the Nu Stable software interface to create / edit the batch files
  7. run reset everything again - Analysis > Sequence > Edit > psi_reset_everything.seq, the click Run
  8. fill out daily log
  9. fill up the liquid nitrogen dewar
  10. place liquid nitrogen lines into the dewar and wrap the fleece cozy around the lines and top of dewar
  11. start - Analysis > Batch > Setup-Full > Open > select your batch file > Run

Acid

Periodically, you will need to simply top off the acid vials. Acid is stored in the larger 60 *C drying oven in 303B. Don liquid protective gloves, unscrew caps, top-off vials.

If we are low or out of the Psi acid (1.90 g / mL), you need to dilute more from the more concentrated stock (~1.95 g / mL).

If we are low or out of all concentrated phosphoric acid, make more.

Do some dishes

  1. With liquid protective gloves on, remove vials from Psi and place in the #1 white tub. The vials can contain acid, sediment, carbonate, and bubble bursters. That is, just set them in the tub regardless of what is inside them. We use the acid to our advantage later.
  2. Fill tub half ish full with DI water.
  3. Remove all air from each and every single vial. YES ALL OF THE AIR. The vials must soak in this acidic environment. If you want to be certain that no carbonate is left inside any vial, this step is absolutely critical. Allow them to soak overnight.
  4. Remove each vial and shake all of the liquid out of the vial back into the tub, NOT THE SINK. Place each vial in the #2 white tub. Fill the #2 white tub half ish full with DI water and, again, jostle air from every single vial. Soak overnight.
  5. Add sodium bicarbonate (baking soda) to the #1 tub while the tub is in the sink. Use the wooden dowel to stir. Add more sodium bicarbonate and stir until it stops fizzing and you see a near neutral pH as measured with pH paper. Then, after you have achieved neutral pH, dump the contents of the #1 white tub down the drain. Left over baking soda is okay. Rinse the #1 tub with DI water and leave on the bench.
  6. Shake all of the DI water out of the vials that were soaking in the #2 white tub and place them into the #3 white tub. Fill the #3 white tub half full with DI water and shake all of the air out of each vial. Soak overnight.
  7. Dump the water remaining in the #2 tub down the drain.
  8. Shake all of the water out of each vial and place them into a clean glass beaker. Place this beaker into the 60*C drying oven near the hood. Make sure the drying oven door closes. You must move the handle to the side to open AND CLOSE this oven. Leave these vials at least overnight or until they are dry.
  9. Dump the water from #3 tub down the drain.

IMPORTANT - This process does not do a good job at removing leftover sediment or otherwise precipitated solids from the vial. It is important to note that the leftover material is NOT CARBONATE. See your bubbling observations from step 5. Yes we all like clean vials, but this unsightly dirtiness is not carbonate. Still, to remove this material, offending vials must be scurbbed with a pipe cleaner. My preference is to go through the above steps and then as I see the dirty vials, which could be while weighing, I separate them out and scrub them on a individual vial basis. Once you have these vials clean, rinse with DI, and dry them in the oven.

Data

Signature

I have read and understood the present SOP and, before starting work outlined in the present SOP, I will complete all required training.

Last updated: 2024-10-21 08:47:17