Dust Trap Processing
Materials (for each trap):
2 500 ml nalgene bottles (for marble rinse)
2 250 ml centrifuge bottles (for pan rinse)
1 ICP tube (8 ml) (if measuring NH4)
1 15 ml falcon tube (for dilution and measurement by IC)
2 0.45 m filters (or 0.2 m if available)
2 petri dishes
2 glass vials
large plastic funnel
spatula
2 filtration set ups
1 3L nalgene bottle
dish pan (cleaned and rinsed with DDI)
tweezers
squirt bottle of DDI water
exacto knife
colander-type thing for rinsing marbles
1. Bottles should be washed and rinsed with DDI and completely dry before starting.
Label bottles and Petri dishes as:
#1 marble (500 ml bottle)
#2 marble (500 ml bottle, this will hold the final sample so include all information)
#1 pan (250 ml bottle)
#2 pan (250 ml bottle, this will hold the final sample so include all information)
marble (petri dish)
pan (petri dish)
2. Weigh #1 pan (others can be weighed later). Cut off duct tape and plastic bags from
dust trap with exacto knife, going around the top edge. Place the funnel on top of the 3liter bottle, and place the bottle in a clean, plastic dish pan. Gently coax marbles little by
little into funnel using spatula. Jiggle funnel to let marbles pass into bottle. If a marble
escapes into the dish pan, retrieve with tweezers. Rinse plastic that was touching marbles
with DDI into bottle and add DDI to cover marbles. Set aside.
3. Add ~200 ml nanopure water in ~50 mL increments to pan, first by rinsing wire mesh
screen into pan, then rinsing inside of remaining plastic bag, and finally rinsing the sides
of the pan itself. After each increment pour into #1 pan bottle. Use a spatula to scrape
off any salt-crusted spots. Beware residual metal fragments from mesh, hole drilling, etc.
– remove with tweezers. Pour slurry into the bottle and repeat as needed. Weigh #1 pan
bottle and solution, making sure the outside of the bottle is dry.
4. Put the bottle with the marbles and #1 pan on shaking table and shake for 30 minutes.
Meanwhile, complete preweighing the remaining bottles, Petri dishes, and filters (using
tweezers to manipulate filters). You will have the following measurements:
#1 marble (500 ml bottle)
#2 marble (500 ml bottle)
#1 pan (250 ml bottle)
#2 pan (250 ml bottle)
marble petri dish
pan petri dish
marble petri dish + 0.45 m nylon filter
pan petri dish + 0.45 m nylon filter
Also, set up 2 filtration units, keeping track of which one is for the marble rinse and
which is for the pan rinse.
4. When the bottles are done shaking, put the #1 marble bottle in the dish pan with the
funnel on top and have the colander ready. Pour the water and marbles through the
colander into the bottle. Rinse the marbles thoroughly, shaking to free trapped water.
Rinse the funnel before removing from the bottle. Weigh the bottle and solution.
5. Filter the solutions in bottles #1 pan and #1 marble. Transfer the filtered solution into
the #2 pan and #2 marble bottles. This may require multiple transfers from the filter flask
into the second bottle. Record the mass of each bottle plus solution. Pour an aliquot into
a 15 mL tube for IC analysis. Immediately freeze samples.
6. Transfer filters back into appropriate Petri dishes. Rinse any sediment stuck on the
side of the upper part of the filter unit into the Petri dish. Freeze overnight and then
freeze dry for a couple of hours. Weigh the Petri dishes and filters. Transfer silicate dust
into small glass vials for chemical analysis.
Summary of Measurements:
#1 marble (500 ml bottle)
#2 marble (500 ml bottle)
#1 pan (250 ml bottle)
#2 pan (250 ml bottle)
marble Petri dish
pan Petri dish
marble Petri dish + 0.45 m nylon filter
pan Petri dish + 0.45 m nylon filter
#1 marble + solution
#2 marble + solution
#1 pan + solution
#2 pan + solution
marble Petri dish after freeze drying
pan Petri dish after freeze drying