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Each sample will correspond to one beaker; collect as many as needed. Beakers need to be cleaned (DI water and isopropyl alcohol) and labeled ( ex. 1, A, or sample label).
Next start the grinding process using the Buehler grinder located in the Xray prep area of the thing section lab (Fig. 1).
Note: Make sure that the correct diamond disc is attached to the wheel. The diamond disc is attached to a magnetic disc which is then placed on the wheel plate. Attach the diamond disc using either the adhesive on the back or an aluminum ring.
Figure 1: Buehler Grinder Polisher. A. On/Off switch B. Power Indicator light C. Timer On/Off button D. Water On/Off switch E. Water flow control knob F. Disc speed control. G. Stop/Start. H. Emergency Stop
To start the polisher flip the 'On' switch in the back. The power indicator light (Fig. 1A) should illuminate. Press the timer button (Fig. 1B) to get continuous disc rotation. Turn the water on by flipping the 'Water' switch to the 'On' position (Fig. 1C). The water flow can be adjusted by turning the knob shown in Fig 1D.
The rotation speed is controlled by the dial shown in Fig. 1E. The range is 0 rpm to 500 rpm. 150 rpm is a good starting position. Adjust the speed if needed: faster for hard rocks and slower for softer rocks.
With the water on and the RPM adjusted press the 'Run' button (Fig 1F). Move the sample back and forth across the disc to prevent making a groove. If there is an emergency press the 'Emergency Stop' button (Fig. 1H) to stop rotation and cut off the water. To enable the wheel again twist the knob until it pops back out.
Polish the rocks until they're completely smooth and round on all edges. There should no pits or jagged corners. Put the rock into a labeled beaker and polish the next sample. Do this for all samples and then move on to 'Cleaning Samples'.
Figure 2. Labeled beaker with polished rock inside
Cleaning Samples
To remove contamination (oil, skin, and residue from the diamond wheel) wash the polished samples in 70% isopropyl alcohol and DI water. From this point onward, wear gloves when handling samples to avoid reintroduction of contaminants.
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Pour either DI water or isopropyl alcohol (70%) into the beaker to cover the sample. Check with the scientists for their preference in solution. There should be enough liquid to keep the sample from floating in the sonic bath (Fig.3).
Figure 3. Sonic Bath
Fill the sonic bath with a little bit of water and place beakers inside. Sonicate for 15 minutes. You should notice the water becoming cloudy from residue being shaken off the samples. Then follow the wash sequence below:
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Place the beakers into the ICP Oven at 110°C for 12 hours (Fig. 5). Turn on the power button and adjust the knob to 110°C, which is marked on the oven. A thermostat is located inside to double check temperature.
Figure 5. The ICP Prep Oven located in the X-Ray lab. A. ‘On/Off’ Switch B. Temperature Setting C. Heating Indicator
After 12 hours remove the beakers from the oven and place them inside the desiccator (Fig. 6) while you prepare the X-press station.
Note: The ICP oven should be kept clean at all times, as samples are left open and are susceptible to contamination. The ICP oven should only be used for ICP samples.
Figure 6. Desiccators located in the X-ray lab
Crushing Samples in the X-Press
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- Weigh Paper 6" x 6"
- Core liner
- Two derlin discs
- Stainless steel base
- Figure 7: Materials needed for assembly of 'crushing unit'. A. Weigh Paper 6"x6". B. Core Liner C. Two Derlin Discs D. Stainless Steel Base E. Aluminum DieAluminum die.
Figure 7: Materials needed for assembly of ‘crushing unit’. A. Weigh Paper 6”x6”. B. Core Liner C. Two Derlin Discs D. Stainless Steel Base E. Aluminum Die
Put on gloves and 'wash' them with isopropyl alcohol. Clean the crushing supplies with isopropyl alcohol and set them down on the clean surface.
Collect sample beakers from the dessicator. Put a piece of parafilm over each beaker and bring them over to the X-press.
Now that the X-press area is clean and the samples are in the lab, assemble the crushing unit as follows:
- Grab the stainless steel dish. This is the base for the crushing unit (Fig. 8).
Figure 8. Stainless stell dish
- Place a piece of Weigh Paper on the Base (Fig. 9).
Figure 9. Dish with Weigh paper
- Put one Derlin disc on top of the weigh paper (Fig. 10).
Figure 10. Derlin Disk Added
- Place the sample on top of the Derlin Disc (Fig. 11). These discs can fracture leaving Teflon flakes in the sample so arrange the sample such that the two flattest surfaces are the top and bottom.
Figure 11. Sample Added
- Now place the second derlin disc on top of the sample (Fig. 12). Again make sure the disc rests flat against sample.
Figure 12. Second Derlin Disk added
- Put the aluminum die on top of the derlin disk, holding it until you slip the core liner over the unit (Fig. 13).
Figure 13. Aluminum Die added
- Now slip the piece of core liner over all the pieces and resting inside the stainless steel base (Fig. 14). This contains the sample pieces inside the unit.
Figure 14. Core Liner added
- The crushing unit is now assembled and we can start crushing samples.
Figure 15: Overview of the X-Press. A. Metal platform sample rests on B. Jacksrew C. Pressure Relief Handle. D. ‘On’ toggle E. Pressure Gauge.
Place the crushing unit inside the X-Press in the middle of the metal platform (Fig. 15 A). Put in the sliding polycarbonate door. Tighten the jackscrew (Fig. 15 B) until it rests firmly against the aluminum die. Tighten the 'pressure relief handle' with a clockwise turn (Fig. 15 C).
Note: The polycarbonate door sits on two interlock switches that enable operation. If the door is not fully closed or pressing down on these switches the machine will not work.
Crush the sample by continuously holding down the toggle switch (Fig 15 D). The motor and pump can be heard and the pressure will rise (Fig 15E). Once the desired pressure is reached the toggle can be released and the sample will sit under that pressure. For most samples ~5 tons of pressure is enough force to crack it. If you find the need to go past 10 tons, try rotating the sample onto another side and apply pressure again.
Note: Always wear safety glasses. Do not stand directly in front of the X-Press while it is operating.
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Turn on the Shatterbox by flipping the 'On' switch located on the back panel (Fig. 16A). The control panel is located on the front of the lid next to the handle (Fig. 16C).
Figure 16. Shatterbox. A. Power switch. B. Cover. C. Control panel
There are two sizes of grinding vessels: small and large. Each size has different components and requires a different setup inside the Shatterbox. The small vessel holds between 5-20 mLs of material and has three components: a container, puck, and lid (Fig. 17).
Figure 17. Small vessel components. A. Container B. Puck. C. LidFigure 16. Shatterbox. A. Power switch. B. Cover. C. Control panel
The large grinding vessel holds between 20 – 60mLs of material and has five components: a container, puck, inner ring, O-Ring, and lid (Fig. 18).
Figure 18. Large Vessel components. A. Container B. Inner Ring C. Puck D. O-Ring E. Lid
The small vessels have a small indent in the bottom of the container and they will sit in the shatterbox resting on either a three pinned plate (Fig. 19) or a one pinned plate (Fig. 20).
Figure 19. Three pinned rack plate to hold three small vessels in Shatterbox
Figure 20. Single pinned rack plate to hold one small vessel in Shatterbox
The three pinned plate will hold three vessels while the one pinned plate will only hold one. If two samples need to be crushed select the three pinned plate. The large vessel will sit directly in shatterbox without an additional plate below it.
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Transfer the sample pieces into the grinding vessel. Pour sample pieces between the puck and the wall of the vessel (Fig. 21). There can't be any material on top of the puck or inside the sealing ring; otherwise the vessel will not seal properly and the sample can spill inside the Shatterbox. If any pieces are on top of the puck or ring, use gloves, tongs, or a KimWipe to move the sample into the vessel. Put on the lid and start assembling the shatterbox.
Figure 21. Small vessel filled with sample pieces. No sample material is on the top the puck or in the lid ring.
Open the lid, pull out the lever arm (Fig. 22A), and pull up the clamp arm (Fig. 22B). This will reveal full access to the inner capsule (Fig. 22C).
Figure 22. The inside of the Shatterbox. A. The lever arm B. The clamp arm C. The inner capsule
Depending on vessel size, you will either put in the pinned plate (small vessels) or the large vessel directly. The shatterbox setup will also vary depending on sample number. If you are crushing one sample use the one pinned plate, whereas for two or three samples use the three pinned plate (Fig. 23). For crushing two samples, two vessels will be full, whereas the third will be empty without a puck. It is important to maintain balance within the machine to prevent damage.
Figure 23. Inside the Shatterbox with the bottom three pinned rack plate resting inside the inner capsule.
Now load vessels onto the plate (Fig. 24). The divet in the bottom of the vessels will settle onto the pins and fit firmly in place.
Figure 24. Three samples loaded into the Shatterbox.
Put the top rack plate over the vessels. Bring down the clamp arm (Fig. 25A). The guide on the clamp arm will settle into the boss (Fig. 25B) when centered properly.
Figure 25. The top rack plate sitting on top of the three samples. A. Clamp arm. B. the “boss” of the rack plate, where the clamp arm will attach.
Bring the lever arm down and push it into the end of the clamp arm (Fig. 26B). Then push the lever arm down over the clamp arm (Fig. 26A).
Figure 26. A. The lever arm inserted into the end of the clamp arm. B. The clamp arm pushed over the lever arm.
The resistance in the lever arm is very important and must be adjusted before use. There should be moderate resistance in the arm while pushing it down. If the resistance is too low the containers can shake free; whereas, if it's too strong the clamp can break. Ideal tightness is just past the point where the vessels can be rotated while the clamp is down. Adjust the resistance by raising the clamp arm and pushing on the 'locking pin.' Hold the locking pin and turn the guide (Fig. 27A). Rotating the guide clockwise decreases resistance; whereas counterclockwise increases resistance.
Figure 27. The lever arm and the guide. A. Retractable locking pin being pushed to allow adjustment of the 'guide' length.
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Now close the lid and turn the emergency stop switch to 'On'. This does not start the Shatterbox but does enable operation. If an emergency shutdown is needed, flip this switch to 'Off' and all shaking will stop even though the timer will continue to count down.
Set the grinding time. The LCD screen displays the current operating time (Fig. 28A). Adjust the time by pressing on the 'Minute' (Fig. 28B) and 'Second' (Fig. 28C) buttons. The timer maximum is 9:59.
Figure 28. A. Current operating time. B. Minute button. C. Second button. D. Start button. E. Pause/Stop button.
When the time is set press the 'Start' button (Fig. 28D). To temporarily pause the operation press the 'Pause/Stop' button once (Fig. 28E).To stop the machine press 'Pause/Stop' twice.
Normal Sounds: The shatterbox is extremely loud. The foam and strap surrounding the shatterbox helps keep it in place and minimize some of the noise.
Abnormal Sounds. If there are any metal on metal sounds shut off the shatterbox immediately. Something inside the shatterbox has probably come loose and will damage the inside of the container.
When the shatterbox cycle is done open the lid and remove the vessels, placing them on the counter. Open the grinding vessel and with clean tweezers take a bit of the powder and feel it against the inside of your wrist. The sample should feel like baby powder, if it does not, repeat the shatterbox cycle.
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- In a vial, mix 400 mg lithium metaborate flux (pre-weighed onshore) with non-ignited, or raw, powdered sample. This step is typically completed by the chemistry technicians.
- Fuse both sample powder and flux into a glass bead (Fig. 29). Dissolve the bead in nitric acid. This solution will be further diluted and analyzed by the ICP.
Figure 29. Fused glass bead.
Weighing the Sample
Note: This process is typically done by the chemistry technicians.
Weighing the ignited sample is a critical step. The sample weight should be as close to 100 mg as possible. Inaccuracies in the weight will show up in the analytical results. Print small labels for each sample and place on your small, clear capped vial. On the lid label a sticker with the core, section, and interval.
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Collect platinum crucibles, platinum tipped tongs, 0.172 LiBr, and pipette tips from the safe above the Bead Maker (Figure 30). Get the 10-100ul pipette and teflon spatula from the drawer and clean with isopropyl alcohol. Have a tray of samples that need to be fused and an empty tray for finished beads.
Figure 30. Bead making supplies. A. Platinum tipped tongs. B. Platinum crucibles. C. 0.172 Libr wetting agent. D. Pipette. E. Teflon spatula. F. Pipette tips.
Turn 'On' the Bead Maker (Fig. 31; switch on the right side of the instrument).
Figure 31. Beadmaker. A. control panel. B. Site of platinum crucible. C. View port window. D. Fan to cool platinum crucible. E. Ceramic plate used for dislodging the fused bead.
Next, turn on the water (Fig. 32; 33). The handle is to the left of the machine on the wall. Raise the handle slightly to turn it on. You will hear a small click once it is in the 'on' position. Now the 'Water' and 'Ready' indicator lights should be on. Do not run any samples unless these lights are on.
Figure 32. Water in off position.
Figure 33. Water in on position.
- Lay a large Kim wipe and a piece of weigh paper down next to the Bead Maker. Unwrap a platinum crucible and place it on the weigh paper. Pour the powder mix into the crucible. The sample should evenly cover the bottom.
- Pipette 10 µL of 0.172 mM LiBr wetting agent into the center of the sample powder.
- Open the Bead Maker lid and place sample inside the sample holder. The short wide crucible will fit directly; whereas, the tall narrow crucible will need an additional ceramic ring.
- Close the lid. Double check both indicator lights are on. Press 'On' to start the program. The process will take 12 minutes and the sample is heated in three stages:
- Stage 1:700°C for 2 min
- Stage 2:1050°C for 5 min,
- Stage 3: 1050°C in agitation for 5 min.
- Be prepared to remove the crucible as soon as the timer is done. The material hardens very quickly so be ready with safety glasses, gloves, and the platinum tipped tongs before the final stage has finished.
- With the Pt-tipped tongs, lift out the crucible and swirl the contents around to get the entire sample into one bead. Wear eye protection! The bead is very hot and rapid cooling can cause it to shatter and fly out.
- Place the crucible on its cooling rack. When seated properly the red light behind it will start flashing. When the flashing stops the bead and crucible have finished cooling down.
- Place a sheet of 6x6 weigh paper on the ceramic plate. Take crucible from the cooling rack and prepare to flip it upside down on the paper to extract the bead.
- With crucible in hand flip over and give it a firm whack on the weigh paper. The bead should pop off without much resistance. Put the bead back into the vial that contained the flux.
- If there are small pieces of bead left behind you can use your Teflon spatula to try pry it off. Do not use too much force. The platinum is malleable and will get scratched and damaged if put under too much force. If it still remains, make a note of the sample number and inform the chemistry technician. The residue (if any) should come off during the cleaning process.
- Repeat process for all samples.
- Hand off all beads to the chemistry technicians to continue on with the ICP analysis.
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Clean the balance area including the balance plates inside the balance. Any dust or particles on the plate could throw off the weight measurements. Before beginning make sure there are enough acid washed quartz crucibles for your samples. The crucibles are located in the X-Ray lab in a plastic container labeled 'Acid Washed Crucibles'. Wear gloves while handling the crucibles.
Place a large sheet of paper in front of the balances and place supplies here. For each sample you need weigh paper (Fig. 34A), a scoopula (Fig. 34C), and a quartz crucible set (Fig. 34B). Clean the scoopula with isopropyl alcohol in between each sample as it has direct contact with the sample powder.
Figure 34. Materials needed for weighing LOI. A. Clean paper or kim wipe. B. Crucible set. C. Scoopula. D. Samples
Setting up the Mettler Toledo Balances
Samples are weighed on the Mettler-Toledo Dual Balance. The Dual balance uses two weighing stations to compensate for shipboard motion: one a 'known' reference weight (Fig. 35A) and the other an 'unknown' sample weight (Fig. 35B). The balance takes a series of measurements and uses the average value as the final weight (for a more in-depth guide refer to the Balance User Guide on Cumulus). Each balance has a control panel plate, which constantly record weight. These plates communicate with the "Mettler Balances" program.
Figure 35. Mettler Balance Station located in the XRay lab. A. Reference balance. B. Unknown balance. C. Sliding door. D. Reference power module. E. Unknown power module
Open the Mettler Balances program (Figure 36). There are multiple panes and parameters that are set before we start measuring.
Figure 36. Mettler Balance program window. A. Graphical measurement window. B. Final weight panel. C. Statistics panel. D. Weigh. E. Tare. F. Halt. G. Options panel. H. History panel.
Graphical Measurement Window: Shows a line graph of the live-time measurement weight and the running average weight.
Final Weight Panel: Displays the Final Weight after all measurement counts have been made
Statistics Panel: Shows the average weight adjusting with time.
Counter Weight: Enter in the reference weight Counts: The elapsed amount of measurements
Tare: Shows and applies the tare or 'zero' value
Sample ID: Name the sample being measured
Commands Panel: Executable commands
Weigh: Starts measurement
Tare: Determines the 'zero' weight. This value is applied to the final weight.
Halt: Stops a measurement before it has gone through all counts
History Panel: Shows statistics on all measurements taken. This file can be exported into an excel file by using the 'Export' button. Note: The 'Export CSV' file does not work.
Options Panel: Editable measurement parameters. We measure using the 'Counts' feature. 'Counts' is active when the dot is blue. Change the number of counts or measurements the balance takes here.
At the beginning of a series of measurements, tare the balances. To do this first make sure that the 'Counter Weight' field is set to '0' and then set the 'Count' value. The 'Count' is dependent of the sea state: 600 for calm waters and 1000 counts for rough waters. If seas are too rough than wait until the weather settles before continuing to measure.
A rule of thumb is that the measurement of a known reference mass shouldn't have a larger deviation than the accuracy desired. For example, our accuracy is +/- 0.05 grams; weigh a reference mass in the unknown balance that is close to the masses you are measuring (e.g., 25 grams) and perform the measurement with the appropriate counterbalance mass in the reference balance pan. You should get a final mass of 24.95—25.05 grams.
Once parameters are set, select the 'Tare' button. When the tare is complete the 'Final Weight' Section turns orange and the 'History' Section updates (Fig. 37).
Figure 37. Mettler Balance program window showing a tare calculation.
Put in a reference weight into the "Reference' balance. With the tweezers, select the 20g weight and place it in the center of the 'Reference' balance. To have a more accurate measurement, the reference weight should be close to the expected 'Unknown' sample weight (roughly ~20g).
Figure 38. Reference weights. A. Weights. B. Tweezers.
Weighing Crucibles
The quartz crucibles have three sections: an outer (or large) crucible, an inner (or small) crucible, and a lid (Fig. 39).
Figure 39. Crucible components. A. Outer (large) crucible. B. Inner (small) crucible. C. Lid.
The inner crucible holds the sample material and is the only piece that is weighed. They are assembled as seen below with the inner crucible inside of the outer crucible and the lid sitting over the entire unit (Fig. 40). Crucible sets (large, small and lid) are engraved and lettered and should be kept as a set. For example, Crucible lid 'A' should always be run with large and small crucible 'A'. If a crucible is unlabeled use a diamond-tipped pen to etch in an unused lid.
Figure 40. Complete and assembled crucible unit.
Weight measurements are recorded in an excel spreadsheet which will be uploaded to LIMS at the end of an expedition (Fig 41). Open the excel spreadsheet titled 'LOI Template' found in Local Disk > DATA and save the spreadsheet in Local Disk > DATA > IN as 'EXP # LOI'.
Figure 41. LOI spreadsheet.
The spreadsheet has multiple columns to fill in.'SITE', TEXT ID', 'CORE/SECT/INTERVAL', 'CRUCIBLE ID', 'CRUCIBLE WT', 'CRU+FRESH SAMPLE WT', and 'CRU+IGN SAMPLE WEIGHT'. 'SAMPLE WEIGHT', POST IGNITION LOSS', and '%LOI' are calculated values based on the weights entered in columns E – G.
The first measurement taken will be the initial weight of an empty crucible. To complete this measurement, open the side door and place an empty inner crucible in the center of the 'Unknown' balance (Fig. 42). Record the number or letter etched onto the crucible in the excel spreadsheet under 'Crucible ID.'
Figure 42. Weighing an empty inner crucible.
Close the door and click 'Weigh'. Wait for the counts to finish and then record the 'Final Weight' in the spreadsheet under 'Crucible Wt'.
Weighing Sample
Weigh out 5 grams of sample powder into the quartz crucible within +/- 0.05g (Fig. 43). The total weight should be the crucible weight + 5 grams within +/- 0.05 grams. For example, a crucible weighs 14.32g, thus the total weight plus the sample will be between 19.27 – 19.37g.
Note: If there is only a small amount of material, you can use less but the %LOI error will be larger.
Figure 43. Crucible with approximately 5g of sample. Pre-ignition measurement
When the sample is close to this range click 'Weigh.' Press 'Halt' to stop the measurement and either add or remove sample if needed, and then click on 'Weigh' again to take a new measurement.
When a sample's final weight is within the allowable range, record the 'final weight' value into the spreadsheet under 'CRU + FRESH SAMPLE WT'.
Carefully remove your sample from the balance. Place your crucible into the larger quartz holder and cover with a lid (Fig. 44). Repeat this process for all samples. After all samples have been weighed and recorded, take samples from the desiccator and bring over to the muffle furnace in the Chemistry Lab.
Figure 44. Complete crucible unit with sample, ready for ignition.
Igniting Samples
Samples are ignited in the Thermolyne Muffle furnace located in the Chemistry Laboratory. The entire ignition cycle takes approximately 20 hours. After ignition, samples need to be taken out when they come down to ~ 50°C-200°C. If the samples sit for too long they will reabsorb moisture and the 'Post-Ignition Weight' will be inaccurate. Time this accordingly.
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Bring crucibles over to the Muffle Furnace (Fig. 45). Turn the power switch on and the control panel will illuminate.
Figure 45. The Thermolyne Muffle Furnace. A. Power Switch B. Control Panel C. Door handle.
Confirm with scientists, what temperature and how long samples should be run for. Below is a quick reference guide:
Material | Ignition Time at °C |
Basalts | 4 or 5 hr at 1025°C |
Si-rich sediments | 4 or 6 hr at ~900°C |
Samples with:
| 6 hr or more at XXX°C |
A common program is an increase in temperature of 3°C/min to a target temperature of 900°C and a hold of one hour. Then ramp up at a rate of 3°C/min to a target temperature of 1025°C and hold for four hours. This ramp cycle is already programmed into the furnace and corresponds to 'Program 1'. To check or edit a program see additional guides attached to the furnace itself. It is also possible to run the furnace manually without a ramp up cycle. Discuss with scientists their preference
Either enter the desired temperature manually or select your program. If you are running the furnace manually, enter the desired temperature; no other buttons or steps are needed. If selecting a program, press and hold 'Run' (Fig. 46).
Figure 46. Control Panel on Thermolyne Muffle Furnace. A. Actual temperature. B. Desired/ Set temperature. C. Run/ stop button. D. Auto run button. E. Page button. F. Scroll button. G. Down button. H. Up button.
When the furnace finishes it's cycle and cools down to ~50°–200°C, remove the crucibles with tongs. Put samples onto a tray and store tray in the desiccator. Keep samples in the desiccator and remove one at a time while weighing. It is very important for the samples to not reabsorb moisture so begin weighing as soon as possible.
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Uploading LOI Data To LIMS
Open the Excel File 'LOI Spreadsheet Upload Template' in Local Disk > DATA (Fig. 47). Put your LOI information into the spreadsheet following the example format. Fill in the Text ID, Analysis, Replicate, Crucible number, and all weights and units including the %LOI. 
Figure 47. LOI Spreadsheet Upload Template.
Open up the program ‘Spreadsheet Uploader’ Pinned to the Taskbar (Fig. 48).
Figure. 48. Spreadsheet Uploader Icon.
Copy and paste your spreadsheet into that uploader. Click the 'Edit' button and 'Validate Sheet'. This checks and highlights any errors that need to be fixed. When the spreadsheet comes up clean, click 'Lims' and 'Upload'. The sheet will turn green when the measurements are successfully uploaded. The data is now in LIMS under Chemistry > ICP-AES Solids >Expanded LOI.
Cleaning the Quartz Crucibles
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