Atmospheric Deposition Field and Lab Protocol

 Atmospheric Deposition Sample Processing

Lab prep:

• 1. Set aside all necessary bottles, vials, tubes, etc.
• 2. Locate and cache all necessary glassware and filters.
• 3. Record bottle numbers on the field datasheet, label N tubes and cation bottles if adequate volume is expected. Label sweater tube trays and sweater boxes.

Lab cleanup:

• 1. Rinse, dry and HCl wash a batch of glassware.
• 2. Wash and leave to dry as many buckets and lids as counter space allows (see Bucket inspection, cleaning, bagging and new bucket prep). Bag and wash remaining as soon as possible.
• 3. Ensure an adequate supply of ashed 25mm GF/F filters (4 hours in muffle furnace at 500 degrees). Filters can be removed from the furnace the following day.

Sample processing:

1. Wipe any soil/debris off the top, bottom and sides of each bucket.

2. Dry Buckets

• 2.1. Using rinsed nitril gloves, open each dry bucket and remove any contamination (insects, bird droppings, etc) with HCl washed and nanopure rinsed forceps. Ensure contaminants are noted on the field data sheet.
• 2.2. Using a rinsed 500ml graduated cylinder, add 500 ml of nanopure water.
• 2.3. With the lid off, swirl the water around the inside of the bucket as high as possible without any risk of spillage. Rest the lid loosely on top of the bucket.
• 2.4. Place each bucket on the orbital shaker for 10 minutes.
• 2.5. Repeat steps 1-4 for each dry bucket, ensuring that all buckets are on the orbital shaker for the same length of time.
• 2.6. Swirl each bucket again by hand.

3. ‘Bulk Samples’ (Dry buckets that have collected rain water due to a collector malfunction)

• 3.1. Add the water from the wet bucket to the dry bucket, then weigh and process as a wet bucket (see Wet Bucket Sample Processing, below) EXCEPT swirl the sample as you would a dry bucket before proceeding.

4. Wet Buckets

• 4.1. Tare the scale in 923 and weigh each bucket. Record the weight in the appropriate column on the field sheet and calculate the net sample volume or use the lab worksheet (\\maricopa\proj\LTER\dm\EMLworkingFiles\eml_protocol\ADP Field-Lab Datasheets.xsl)

5. All Buckets

• 5.1. Using rinsed nitril gloves and avoiding contact and contamination remove the lid and carefully pour a small amount of each sample (~5 to10ml) into the appropriate HCl washed 500ml bottle.
• 5.2. Cap and rinse the bottle. Discard the rinse.
• 5.3. Pour the remaining sample into the bottle. If the sample is greater than 500ml, simply decant 500ml off the top and discard the remainder.
• 5.4. Replace the lid on the bucket and set it aside to be cleaned
• When necessary buckets can be left in the cold room overnight. Wet buckets must be allowed to acclimate at room temperature for 2-4 hours before weighing.
• If there is less than ~10ml of sample in the wet bucket, note this on the datasheet and do not process the sample. If the sample bottle volume is limited (i.e. 10-140 ml) or lost, strike the unprocessed subsamples on the datasheet.
• If the sample bottle volume is otherwise limited (i.e. 155 less than 290 ml) samples should be split roughly 60% anions / 40% cations. [Sample of 155 greater than 290 ml leaves 75-210 ml available for analysis; 75 x .4 is 30 ml (min) and 210 x .6 ≈ 125 ml (max)]

1. Nitrogen (NH4 ammonium and NO3 nitrate)

• 1.1. Label one HCl washed plastic centrifuge tube for each sample with the 3 letter site name and indicate if wet (W), dry (D) or bulk (B).
• 1.2. Cap the tube and rinse with a small amount of sample (~1ml). It is not necessary to rinse plasticware with nanopure first.
• 1.3. Fill the centrifuge tube within 5 mm of the top with about 6ml of sample.
• 1.4. Repeat steps 1-3 for each sample
• 1.5. Centrifuge the tubes together for 10 minutes at 11000 rpm’s.
• 1.6. Ammonia storage
• 1.6.1. Place the ammonia tubes in a tube tray labeled with the date and “ADP N” on a strip of med tape, then store the tubes in the cold room (in back of GWEL 675) until they can be run, preferably within 12 hours of collection.
• 1.6.1.1. If necessary, each sample can be acidified with 2μl of sulfuric acid for each 1ml of sample. Label as acidified.

2. DOC (Dissolved Organic Carbon)

• 2.1. Using one HCl washed, nanopure rinsed scintillation vial (30 ml glass vial with a blue cap) for each sample, record the label from each vial on the field datasheet.
• 2.2. Use nanopure to rinse an HCl washed 25mm filter apparatus (filter flask, fritted base and filter funnel). Discard the nanopure rinse.
• 2.3. Place an ashed 25mm GF/F filter in the apparatus.
• 2.4. Filter about 10 ml of sample, rinse the filter apparatus, then discard the sample rinse.
• 2.5. Filter between 15 and 30ml of sample.
• 2.6. Rinse the appropriate scintillation vial with about 3 ml of the filtrate, then discard the rinse.
• 2.7. Pour the remaining filtrate into the vial.
• 2.8. Cap the vial and place it in a tube tray.
• 2.9. Rinse the filter funnel with nanopure separately before beginning the next sample. Repeat steps 1-7 for each sample.
• 2.10. DOC acidification and storage
• 2.10.1. 3x rinse a 10ml beaker with nanopure, then with a small (less than 1ml) volume of concentrated HCl. (CK says DOC vials may also be acidified as they are run, if they are run “soon” after filtration).
• 2.10.2. Discard rinse and fill with another small vol. of HCl
• 2.10.3. Use a glass pipette and bulb to deliver one drop of concentrated HCl for each 15 ml of filtered sample
• 2.10.4. Label the tube tray with the date and “ADP DOC, acidified”, then place it in the cold room until the samples can be run (preferably w/in 24 hours).

3. Anions (PO4 and Cl) and Cations (Ca, K, Mg, Na)

• 3.1. Using one HCl washed and (if adequate sample volume) one HNO3washed, nanopure rinsed 125 ml Nalgene bottle for each sample, record the label from each bottle into the appropriate cell on the field datasheet.
• 3.2. Use nanopure to rinse a HCl washed 47mm filter apparatus (filter flask, fritted base and filter funnel). Discard the nanopure rinse.
• 3.3. Place a Supor-450 47mm membrane filter (0.45 micrometer filter) in the apparatus.
• 3.4. Filter and then rinse the filter apparatus with about 15ml of sample, then discard the sample rinse.
• 3.5. Depending on wet bucket sample volume (see Wet Bucket Sample Processing Matrix, above) filter between 35 and 260ml of the remaining sample.
• 3.6. Anion processing
• 3.6.1. Rinse the appropriate 125ml HCl washed bottle with about 5ml of sample and discard the rinse.
• 3.6.2. Pour between 30 and 125 ml of sample into the HCl washed bottle.
• 3.7. Cation processing
• 3.7.1. Rinse the appropriate 125ml HNO3washed bottle with about 5ml of sample and discard the rinse.
• 3.7.2. Pour between 30 and 125 ml of sample into the HNO3washed bottle.
• 3.8. Rinse the filter funnel with nanopure separately before beginning the next sample. Repeat steps 3.2-3.8 as appropriate for each sample. (see Wet Bucket Sample Processing Matrix, above)
• 3.9. Anion storage
• 3.9.1. Once all the anion samples have been processed place the bottles in a sweater box labeled with the date and “ADP Anions” and store in the cold room until they can be run, preferably within 24-48 hours of collection for reactive species.
• 3.10. Cation storage
• 3.10.1. Label each bottle with the site name and sample date on med tape and place in a labeled sweater box inside the cabinet on the south wall of GWEL 639.
• 3.10.1.1. If necessary, each cation bottle can be acidified with 0.893 ml of ultrapure nitric acid for every 125ml of sample.
• 3.10.1.1.1. Record the total weight of each bottle on the field datasheet and use the lab worksheet here to calculate microliters of HNO3to pipette, or multiply the net sample weight in each bottle by 7.144 (893/125) for the microliters of acid to pipette.

Questions/Answers/Additions:

1. Where to store cations before acidification?

2. Is cation sample contaminated by the 500ml HCl washed bottle?: per DH No, brief exposure to HCl is acceptable.

3. Revise bucket cleaning protocol

4. Include phone numbers on datasheet?

5. Who acidifies DOC tubes?; I do if sample will be run soon. Label vials.

6. Do bulk samples need to go on the orbital shaker?

7. ADP cations (and poss. others?) have tracking numbers. Am I labeling samples correctly? Will discuss 8/28.

8. How should we measure rain depth in the wet buckets without contaminating? If estimated, why record on datasheet? Visually estimate. See 6/20 field datasheet for sample volume gauge.

9. Schedule to run blanks every 4 months

10. If volume is adequate, for amm., and DOC but not amm. and anions, why not just do amm and DOC? The QC 8000 can analyze nh4 and nitrates from the same ~6ml sample. The anion bottles can also be analyzed for nitrates (as they were on the traacs), but this is no longer necessary? Maybe a better sample priority would simply be nh4/nitrates, DOC, anions, cations, then 30ml DOC if vol allows? Does knowing that nh4 and nitrates can now be run together change anything else? We still need to prep anion bottles, right? After about 7/1 we can run nh4 and no3 from the same centrifuge vial, and more than 15ml for DOC is unnecessary so we can save that for archive. The protocol has been updated to reflect the change

11. As of 6/20/2000 wet buckets will be sampled for each rain event instead of the Tuesday following a rain event. When will we say a rain event is over?

For pH analyses, these should only be done if there is 90-120ml of sample (use a minimum necessary amount from remaining portion of the sample, after 30ml have been set aside for anion analyses); OR more than 120ml of sample (again use the smallest amount of water possible to run pH on, once you have made sure there is at least 30ml to set aside for anions and 30ml to archive for cations). If the volume of sample collected is less than 90ml we will not do pH. Let me know if above not clear.

Preparation

• 1. Wet buckets will be sampled on a priority basis (BRD, LDS, SYC and PSS) for each rain event where other sites are physically or practically inaccessible. (incl. In protocol asap)
• 2. Coordinate with GWEL staff for runs. Better yet, coordinate with stream lab, WMP.
• 3. Ensure adequate supply of 25mm GF/F filters are ashed for 4 hours at 500 degrees.
• 4. Make a note explaining when to run blanks, when to sample wet buckets, when to sample dry buckets, when to sample both and when to bulk a sample; Bulk wet buckets with dry deposition if open more than 1 day.
• 5. Lab Coats?
• 6. Bottle Labelling: ADP####
• 7. Avg. HNO3 125ml bottle tare wt is 23.72g (n equals 10)

Author(s): Diane Hope ,Jonathan Allen, Stevan Earl
Data Manager, Global Institute of Sustainability, Arizona State University,
POB 875402,TEMPE
 caplter.data@asu.edu