TITLE: VarioMax Cube CN SOP
AUTHORS: USDA

[DESCRIPTION]
<div class = "text-blocks"><div class = "text-block">VarioMax Cube CN SOP.</div></div>

[STEPS]
?. [System Startup]
If the VarioMax is sleeping, the temperature and pressure status view should be as shown below:Zero input and output pressure, and zero He and O2 flow. Column temperatures should be:Combustion: 900CPost-combustion: 900CReduction: 830C
?. [System Startup]
Set gas pressures:
?. [System Startup]
Verify He cylinder pressure > 700psi, output pressure 380kPa (3.8bar)
?. [System Startup]
Verify O2 cylinder pressure > 100psi, output pressure 250kPa (2.5bar)
?. [System Startup]
Empty crucible container:
?. [System Startup]
Reset crucible maintenance interval under the menu command:Options > Maintenance > Intervals
?. [System Startup]
Wake up instrument:
?. [System Startup]
Click on the wake-up button (clock) on the main toolbar or under the menu command:Options > Settings > Sleep / Wake up…
?. [System Startup]
Once wake-up is completed the status view will look like this:
?. [Sample Prep and Sample Run]
Enter sample names and weights:
?. [Sample Prep and Sample Run]
Select the appropriate template for the type of sample to be analyzed: soil or plantPlant template MDSoil template MD
?. [Sample Prep and Sample Run]
A typical sample run will contain 3 blnk, 3 RunIn, and 3 standards (aspartic acid) at the beginning of the run and a check standard every 20 samples. A reduction column can accommodate a run of approximately 120 total samples, including standards etc.
?. [Sample Prep and Sample Run]
Click on the corresponding Name cell to input the sample name. Assign Blanks a mass of 1. Every other sample and standard must have a non-zero mass or the sample run will stop when the current sample (green highlighted line) reaches a row with a red box next to the row number. Sample weights will be transferred directly from the balance to the yellow highlighted line in the sample spreadsheet when the “print” button on the balance is pressed. To select the row for weight transfer, use the menu command:
?. [Sample Prep and Sample Run]
Edit > Current weight…
?. [Sample Prep and Sample Run]
Save sample log:
?. [Sample Prep and Sample Run]
Save sample spreadsheet with identifying name. For example:        Plant template MMDDYY Name Surname
?. [Sample Prep and Sample Run]
Do not change the location where this file is saved. A copy of the file can be exported to another directory as described the Data Export section.
?. [Sample Prep and Sample Run]
Load crucibles in sample carousel:
?. [Sample Prep and Sample Run]
Carefully lift plastic carousel cover a few inches and slide off carousel. Note that removal or misalignment of the cover triggers a software warning.
?. [Sample Prep and Sample Run]
Place crucibles in corresponding carousel position, according to sample log Hole Pos.
?. [Sample Prep and Sample Run]
Replace carousel cover.
?. [Sample Prep and Sample Run]
Start sample run:
?. [Sample Prep and Sample Run]
Click the multi-sample button on main toolbar.
?. [Mid Run Maintenance]
Recovering crucibles:
?. [Mid Run Maintenance]
Click the single-sample button on the main toolbar. The sample run will pause at the end of the current sample analysis and the VarioMax will go into Standby mode.
?. [Mid Run Maintenance]
Recover empty crucibles as described in the System Startup section.
?. [Mid Run Maintenance]
Restart the sample run by clicking the multi-sample button on the main toolbar.
?. [Mid Run Maintenance]
Changing helium cylinder
?. [Mid Run Maintenance]
Click the single-sample button on the main toolbar. When the sample completes, put the VarioMax to sleep by clicking the sleep button (moon) on the main toolbar. The Sleep /Wake up options dialog will open:Un-check all 3 checkboxes to Reduce oven tempClick Sleep now… button
?. [Mid Run Maintenance]
Once the pressures and flows have dropped to zero you can change the He cylinder.
?. [Mid Run Maintenance]
Now Wake-up the VarioMax using the menu commandOptions > Settings > Sleep /Wake up…Re-check the checkboxes to Reduce oven temp so that the corresponding column temperatures will be reduced at the end of the sample run.Open the gas cylinders and set pressures to the following values [He: 3.8bar, O2: 2.5bar]Click Wake up now… button
?. [Mid Run Maintenance]
When pressures and flows have reached the appropriate levels, restart the sample run by clicking the multi-sample button on the main toolbar.
?. [Data Export]
Export analysis results:There are 2 options for data export: sqlite database file and csv
?. [Data Export]
To export as sqlite database file: File > Export/Import > Export…
?. [Data Export]
To export as csv: File > Export/Import > Export sheet data (for Excel)…
?. [Data Export]
Export the results to the folder corresponding to supporting researcher.…\Documents\Vmax\data\ [Baker, Feyereisen, Rice, Spokas, Venterea]
?. [Filling the Reduction Tube]
Fill the reduction column by the end of the day so that it is ready to be swapped the following morning. For more details on reduction column filling see pages 265-267 of the VarioMax manual.