Chemistry Lab Technician SOP

I. Pre-Expedition

• See General JRSO Shipboard Technical Staff SOP

II. Port-call / Start of an Expedition

• Do a thorough cross-over with off-going Chemistry Technicians: read Tech Report in advance, discuss each instrument separately and bring to the attention of the ALO/LO any equipment requiring immediate attention (repairs, spare parts etc).

• Unpack new supplies and store in their correct location. Remember to mark on the bag/container the current Expedition number.

• Do a physical count of critical items.

• Conduct an inventory of chemicals in the storage cabinets. Look for any chemicals not on our inventory, unmarked containers or reagents or mixtures left over from the previous expedition. Bring any issues to the attention of the LO.

• You should calibrate as many instruments as you can. Instructions are in the instrument-specific User Guides. 

• Make as many reagents as you can.

III. Site preparation / Prior to arrival on site and core-on-deck

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  • Provide safety tour to all scientists working in the Chemistry/MBIO area. Ensure scientists understand all safety concerns and that they sign the required documents.

  • Provide training to all chemistry scientists on instrument operation, sample preparation and data upload/download procedures.

  • Meet with chemistry scientists and find out their general goals and specific requests. If there are microbiologists sailing, make sure that these same protocols are done with them.

  • Divide up responsibilities among the Chemists for all shipboard analyses. Follow up during coring operations to make sure all analyses are done and done correctly

  • Have a meeting with the Chemists/Curator/SAC (Sample Allocation Committee) to go through sample plans.

  • Prepare sampling equipment and sample storage containers. Wash any necessary containers and prepare spikes if needed.

  • Prepare SampleMaster split template (water and squeeze cake splits).

  • Show how to print sample labels.

  • Go over all SDS sheets before working with any chemicals. Understand the risks of handling chemicals, especially if any hazardous chemicals will be used.

  • Print out the most recent copy of each instrument's User Guide so the scientists can become familiar with each instrument's operation.

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  • Alkalinity/pH/chloride titrations

    • Alkalinity: Prepare 20 mM and 40 mM standards if necessary 

    • Chlorinity: Prepare 2 liters of dilution solution

  • Coulometer

    • HCl solution, KOH and AgNO3 solutions if needed

  • IC 

    • all solutions except for anion eluent, which should be made shortly before analysis

    • pourable calibration standards

  • ICP

    • 2% and 3% TM nitric acid solutions, also 10% if analyzing hard rock

    • internal standard(s)

    • primary in-house cocktail

    • pourable in-house and IAPSO calibration standards

  • SPEC

    • Ammonium

      • Ammonium standard (dry ammonium chloride in oven overnight) + calibration standards

      • alkaline solution

    • Phosphate 

      • Phosphate primary standard (dry monobasic potassium phosphate in oven overnight) + calibration standards

      • Sulfuric acid solution

      • Antimony potassium tartrate solution

      • Ammonium molybdate solution

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  • 25/50 mL plastic syringes (acid-washed).

  • 0.45µm Whatman disk filters.

  • Take four boxes of 9 cm #1 Whatman filters and soak them in a large beaker of DI water for ~ two hours, then oven-dry at a low temperature (~50 ^oC). When they are dry, store them in Ziploc bags near the Carver presses. You may need to do this again during the Expedition.

  • Obtain necessary containers for IW sample splits. At the Scientist's request they may need to be rinsed with DI water/acid washed and dried. Also prepare necessary sample spikes.

  • Bags for squeeze cake splits and baked aluminum foil (if required, bake at 500 ^oC for 8 hours).

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  • Headspace sampling tools and containers (vials, septa, headspace tool, plunger, crimper). The septum has a shiny thin creamy color PTFE layer and a thick white matte silicone layer. The shiny PTFE side goes against the vial.   

  • Gas void assemblies (50 mL syringe and three-way stopcock, with male luer lock, attached to the core liner puncturing tool).

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  • Paper towels

  • Kimwipes

  • Pipette tips

  • P-boxes (for sample storage; foam ampule holders for glass vial storage)

  • Gloves, various sizes

  • Boxes for cryovials

IV. During coring operations

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    • Obtain the IW sampling interval from the Curator and take the sample(s) when the core comes on deck.

    • If possible, have the geochemist assist you in determining where to take the IW sample. Never take a sample that includes a change in lithology.

    • Initially, 5 cm whole rounds are taken; as the water yield decreases, go to 10 cm whole rounds. Larger whole rounds may be taken after speaking to the SAC (Curator, EPM, and co-chiefs).

    • If possible, take the IW sample from the bottom of the same section every time. As recovery decreases you will have to take the IW sample from wherever you can.

    • A typical IW sampling plan is one IW per core. Check with the Curator on the current plan.

    • Note the core, section and interval of the sample and write it on the Curator's logsheet. The interval will be entered into SampleMaster by the Curator/ALO.

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    • Take a 5 cc headspace sample from every sediment core (non-basement), at the top of a section (try to be consistent). This sample is taken until the total depth objective is met. If doing multiple holes, you do not have to repeat the sampling if a headspace sample has already been taken at that depth but just continue after the prior hole's bottom depth.

    • For cores with IW samples, always take the headspace sample adjacent to IW, best from the top of the section immediately below the IW sample. Note the core, section and interval of the headspace sample and write it on the headspace vial. The interval will be entered into SampleMaster by the Curator/ALO.

    • Make sure nobody sprays acetone on the catwalk before sampling is completed. Acetone will contaminate the sample.

    • It is recommended to occasionally take a sample of the air on the core deck, so that any change in the headspace sample analysis can be correlated to changes in volatilized acetone.

    • Inject a standard (corresponding to concentrations seen in the recent cores) every fifty injections or so, to check on the instrument calibration.

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    • If gas voids are present in the core liner, take a sample using the syringe vacutainer and directly inject into a GC (NGA1 or NGA2).

    • Circle the hole in the core liner. Note the core and section of the sample and write it on the Curator's logsheet. The interval will change after curation is done on catwalk and it will be entered into SampleMaster by the Curator/ALO.

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    • Removing the sample from its core liner.

    • Trimming the outer surface of the core (sides, top and bottom) of any drilling contamination (until the consistency seems less saturated; if "biscuits" are present, make sure you trim all surfaces of the "biscuits"); maintain proper spatula orientation (contaminated side is always out, sediment side is always in).

    • Put the trimmed sample into a squeezer, then the Teflon disc, rubber disc and piston.

    • Place the assembled squeezer in a Carver press, and bag the residual scrapings, IWSCRAPES.

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    • Set the pressure to 3000 lbs and simultaneously push and hold both green (CLOSE) buttons on the hydraulic unit's base until the auto-pressure engages.

    • After the first drops flow from the hole in the squeezer's base plate, insert the syringe into the hole. Keep an eye on the syringe to make sure the pressure doesn't push out the syringe or plunger (especially for the first few cores). Keep incrementing the hydraulic unit pressure in steps of 1000 lbs until 10000 lbs; after 10000 lbs, increase in steps of 2000. Do not ever increase the pressure above 30000 lbs.

    • Select the correct core, section and sample in SampleMaster. Upload the IW sample splits (using the Excel template) into SampleMaster and distribute the labels.

    • When porewater yield is sufficient/no more water is trickling, release the hydraulic unit pressure by pressing the red OPEN button and remove the syringe from the squeezer.

    • Start sample distribution (splits).

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    • Alkalinity/pH - If there is ample water, allocate 5 mL for shipboard analyses (alkalinity, salinity, IC, SPEC). Speak with the scientists about which analyses they would or wouldn't like performed (ie. Make a priority list). Extra water may be used for repeat analysis or stored (sent back to the repository).

    • Scientific party - split and store the remaining water into the requested aliquots as outlined by the sampling plan. Each sample's storage/preservation is up to its requestor.

    • ICP – 1 - 2 ml; must be acidified with trace metal-grade nitric acid (~ 10 µL).

    • Remove the plunger from the syringe, rinse with DI water and place in the HCl bath for twelve hours. Rinse the components with DI water and bake dry at a low temperature. When completely dry, reassemble syringes and store them in ziploc bags.

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    • Remove the base and the base plate; place the white wood-framed squeezecake extracting platform onto the manual (left-most) Carver press. Place the remaining squeezer assembly onto the platform. 

    • Close the release valve on the bottom of the press (turn valve to the right) and begin manually pumping the Carver press until the squeezecake, Teflon disc, rubber disc and piston are pushed out.

    • Split the squeezecake as per the sampling plan, bag and label the sample(s).

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    • Scrub and rinse the squeezer components.

    • Be sure to flush DI water through the base and the base plate. Blow-dry both. Wipe all components with Kimwipes.

    • Ensure the squeezers are COMPLETELY dry before reassembling. Make sure that the components of each squeezer remain in the same set.

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  • This job necessitates proper inventory technique. After you have located the desired item and physically removed it from its store, go to the AMS inventory checkout sheet and locate said part (by description or part number). To the right of its information are several blank lines; at the corresponding line, write the number checked out (note the unit: each, box, foot, etc) on the line and circle the number.

  • Verify a physical count of all essential parts (without these the lab cannot operate). Notify the ALOs/LO if the counts are off.

  • Familiarize yourself with the storeroom inventory check-in/check-out system.

• Once a shift, clean glassware. If glassware/plastic is in the acid bath, rinse it three times with DI water and let dry. Rinse dirty glassware/plastic three times with RO water and place in bath for twelve hours. Do not put metal objects in an acid bath.

• Make new acid baths when they get dirty and whenever going from flux to IW ICP analyses, make a new nitric acid bath.

• Check the manifold pressures of the helium and argon racks daily.

• Ensure that the active hydrogen generator's water reservoir is full of DI water. Do not let these run empty. Occasionally check the desiccant.

• Coulometer Cathode/Anode solutions: these solutions need changing every 2-3 days or 200 runs. Along with the solutions, you will want to change out the pre- and post-scrubber solutions. Any precipitate in the lines should be removed as well. The solutions will also need to be changed if a 100% CaCO₃ standard check does not come within 100 ± 2%.

• Weekly test the safety shower and eye wash stations.

• Many filters/traps need to be changed on about a weekly basis (check them frequently): 

  • IC, titrators, SRA - drierite

  • EA - (magnesium perchlorate) if hydrogen not being measured.

• The nanopure pre-filters and Barnstead filters need to be changed when an indicator light on the unit comes on. See the manual for how to change these. The nanopure final filters should be changed about every four months.

• Check the freeze-dryer daily for any ice build-up and defrost as necessary.

V. End-of-Expedition activities

• Write the End-of-Expedition lab report and send a copy, via e-mail, to the on-coming technicians.

• Make sure all data is sent to LIMS and all raw data files are copied to the Data1 volume. 

• Pack up equipment being returned for repairs and give the ALO the following information: IODP inventory number, value, serial number, model number, vendor's name and country of manufacture.

• Pack up all samples as per scientists' requests; work with the Curator/ALOs.

• Give the LO a list for port purchases, if any.

• Clean the lab and assigned area following the cleaning instruction according to LO's list. Bring all the trash to the incinerator. Glass and sharps get disposed of in port call.

• Check the oil in the freeze dryer's vacuum pump.

• Defrost and clean the freeze dryer.

• Clean (defrost if necessary) the fridges; dispose of old reagents.

• Check the ovens for debris. Clean them. 

• Clean any instrument-specific items.

• Have the lab coats laundered (segregated and tumble dried).

• Check expiration dates on chemicals, notify ALO/LO if there are hazardous chemicals/waste to be disposed of in port.

• Confirm that both helium and argon have a new full rack of gas bottle connected and ready to go.

VI. Port call – Off Going

• See General JRSO Shipboard Technical Staff SOP