TITLE: Auto-Block Plus Digester Protocol
AUTHORS: William Brigman, Paul Shumaker

[DESCRIPTION]
<div class = "text-blocks"><div class = "text-block">Previous Auto-Block Digester protocols developed by Aprel Ellison and Paul Shumaker</div></div>

[STEPS]
?. [DAY 1]
Pipette 5mL (liquids) or weigh 0.15g (solids) into digestion tubes (always include at the end of the samples 2 blanks and 2 standards– see “standard section” for more detail)(Up to 50 samples + 2 standards + 2 blanks = 54 total)
?. [DAY 1]
Number the digestion tubes accordingly.
?. [DAY 1]
Place disposable reflux caps on all digestion tubes.
?. [DAY 1]
Place digestion tubes in auto-block from front to back and then left to right (filling the first column completely before moving to the second column).
?. [DAY 1]
Check that the compressed air is on if it is not already on:The pressure gauge should be between 20-30psiIf off, open by turning the knob on the counter top behind the auto-block computer.
?. [DAY 1]
Turn the auto-block on with the switch on the front top left-hand corner of the instrument.
?. [DAY 1]
Turn the auxiliary fan on (fan above auto-block) with the switch located on the power cord. This fan should always remain on until everything is complete.
?. [DAY 1]
Double check to make sure the fume hood is on.The fume hood should remain on all the time.
?. [DAY 1]
Logon to the computer next to the auto-block (Username: Autoblock, Password: envexp)
?. [DAY 1]
Open the Auto-block program from the shortcut on the desktop titled "AutoBlock Plus"
?. [DAY 1]
A warning will come up indicated the motors will be sent to the "home" position, hit "OK"
?. [DAY 1]
A warning about Service attention requirement may pop up (depending on if anything is overdue). Press “OK”.
?. [DAY 1]
Go to the “Service tab” in the software and complete any service/maintenance that is due and update the counters in the software if it has been completed. If you have any question contact William Brigman.
?. [DAY 1]
Go to the "Manual Screen" by hitting the Manual Screen button.
?. [DAY 1]
Another warning will come up indicating the motors will be sent to the "home" position will appear, hit "OK."
?. [DAY 1]
Hit "Initialize" button in the bottom left corner.
?. [DAY 1]
Once again a warning about the motors being sent to the "home" position will appear, hit "OK."
?. [DAY 1]
Hit "Move to Drain" button in the bottom left corner (the dispensing arm will move over the drain)
?. [DAY 1]
On the Fan Control (bottom left) move the gray button to the "On" position
?. [DAY 1]
On the Rack Position, located in the bottom middle of the screen, click on "Fill" to move the rack to the fill position.
?. [DAY 1]
Make sure all indicating lights in software are green and not red.
?. [DAY 1]
Purge the dispensing line with H2O:
?. [DAY 1]
Select reagent 1 "H2O" on the Reagent Selection at the top left of the screen by clicking on it with the mouse
?. [DAY 1]
Enter "20" into the Injection Amount under injection control
?. [DAY 1]
Hit "Inject" button underneath the Injection Amount
?. [DAY 1]
Make sure the arm is over the drain and no cells are selected yet
?. [DAY 1]
Purge and prep lines with HNO3:
?. [DAY 1]
Select reagent 2 "HNO3" on the Reagent Selection at the top left of the screen by clicking on it with the mouse
?. [DAY 1]
Enter "5” into the Injection Amount under injection control
?. [DAY 1]
Hit “Inject” button underneath the Injection Amount
?. [DAY 1]
Make sure the arm is over the drain and no cells are selected yet.
?. [DAY 1]
Select all cells (to green) that are filled with digestion tubes in the "Cell Position Selection" portion of the software.
?. [DAY 1]
Add 5mL HNO3 to each digestion tube (samples, blanks, & standards)
?. [DAY 1]
Enter 5.0 into the injection amount box
?. [DAY 1]
Hit "Inject" button underneath the Injection Amount
?. [DAY 1]
Make sure all highlighted cells have digestion tubes or HNO3 will be injected into the block.
?. [DAY 1]
Wait for Auto-block to dispense HNO3into all of the highlighted cells.
?. [DAY 1]
Un-highlight all cells in the "Cell Position Selection" portion of the software.
?. [DAY 1]
Hit the "move to drain" button in the bottom left corner of the software (dispensing arm will move over the drain).
?. [DAY 1]
Purge the line with water to clean out excess acid in the line:
?. [DAY 1]
Select reagent 1 "H2O" on the Reagent Selection at the top left of the screen by clicking on it with the mouse
?. [DAY 1]
Enter "20" into the Injection Amount under injection control
?. [DAY 1]
Hit "Inject" button underneath the amount
?. [DAY 1]
Make sure the dispensing arm is over the drain and no cells are highlighted
?. [DAY 1]
Allow samples to sit in the digester with HNO3 added until the following morning with both fans running.
?. [DAY 2]
Open the “Operator Test” tab in the software.
?. [DAY 2]
Click “Select Method” – a window will open with a list of all the methods.
?. [DAY 2]
Scroll down and select one of the following methods “Wisconsin Liquids” or “Wisconsin Solids” by double clicking on method.
?. [DAY 2]
Once a method is selected, the window will close and goes back to the software. Make sure the correct method is showing in the top left box under “Selected Method File”.
?. [DAY 2]
Enter operator’s name.
?. [DAY 2]
Highlight the cells that are needed for the digestion.
?. [DAY 2]
Press “Start Method”
?. [DAY 2]
A pop up window will appear asking for pre-test requirements (One will ask to ensure reagent bottles are filled, the other will ask to ensure door is closed)
?. [DAY 2]
Check to make sure and then put a check in each box and press “ok”
?. [DAY 2]
The digestion is now running – Periodically check on the digestion. The digestion time is dependent upon the number of samples. A full digestion takes 6-7 hours once started
?. [DAY 2]
After the run is complete, the software will have “completed” at the bottom and all the digestion tubes should be filled about 48mL.The internal fan will turn off once the temperature of the block falls below 40 degrees.
?. [DAY 2]
With gloves on, remove all the disposable reflux caps and discard.
?. [DAY 2]
Take digestion tubes out of block, cap, and shake.
?. [DAY 2]
Using a squirt bottle filled with DI water, finish filling the digestion tubes (by hand) to the 50mL mark.
?. [DAY 2]
Once all samples are removed from the block and capped, the auxiliaryfan can be turned off using the switch or either left on if another run is immediately following.
?. [DAY 2]
The samples now must be filtered using a 0.45 or 2µm filter and plunger. BE SURE TO WEAR LAB COAT, GLOVES, AND EYE PROTECTION AND WORK OVER THE SINK FOR THIS BECAUSE THE SAMPLES ARE HIGHLY ACIDIC AND CORROSIVE.
?. [DAY 2]
The filtered samples are now ready for analysis and have a 6% HNO3concentration.
?. [DAY 2]
Leave the system on until the internal fan shuts off, then turn off the auxiliary fan with external switch on power cord and turn off the auto-block using switch on front of instrument unless another run is immediately following.