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Link to US Geological Survey
Coastal and Marine Geology Program
Woods Hole Field Center

Geochemical Sediment Analysis Procedures, Open-File Report 02-371


Materials Required:
  • Mortar and Pestle
  • Plastic Spoon (not shown)
  • Weighing Paper
  • NYLON Brush (not shown)
  • Kimwipes (not shown)
  • 20% Hydroxylamine Hydrochloride
  • 5% HNO3
  • Deionized Water (18.2 megohm) also called Milli-Q Water
  • Sample
  • Waste Container (not shown)
  • Counting Jar
  • 10 dram Polyvial
Grinding preparation materials; link to larger image

Rinse the agate mortar and pestle with warm, soapy, tap water and scrub it out with a NYLON brush.
DO NOT use a brush with a wire at the core. The wire adds metals to the mortar surface and is potentially a large source of contamination.

Rinse with tap water.

Wipe the surfaces of the mortar and pestle with a Kimwipe.

Wash with soapy water

Squirt approximately .25 mL of 20% hydroxylamine hydrochloride solution into the mortar.

Using the pestle, work the 20% hydroxylamine hydrochloride solution over all of the surfaces of the bowl.

This reducing agent will dissolve manganese and iron oxides.

Pour off the hyroxylamine hydrochloride into a waste container.

Clean with Hydroxylamine Hydrochloride; link to larger image

Squirt approximately .25 mL of 5% nitric acid into the mortar.

Using the pestle, work the 5% nitric acid over all of the surfaces of the bowl.

Pour off the 5% nitric acid into a waste container.

Clean with Nitric Acid; link to larger image

Rinse at least three times with copious amounts of Milli-Q water.

Place the mortar and pestle in a filtered air laminar flow hood to dry.

Milli-Q into mortar

Empty the contents (approx. 16g) from the specimen container into the clean and dry mortar.

If sediment has adhered to the walls of the specimen container, scrape this off using a clean plastic spoon, the pestle, or a titanium spatula.

Empty sediment into mortar

Disaggregate the entire sample to the point that aggregates are broken but individual grains are not ground.

The disaggregated sample will be used for Gamma Analysis.

Disaggregate sediment
Pour sediment onto a piece of weighing paper and transfer into a counting jar. Pour sediment onto paper
Immediately spoon 3-5 grams of sediment onto a tared piece of weighing paper on a balance.

Weigh sediment

Pour the weighed sediment back into the mortar.

Continue grinding until the sediment is no longer gritty (like face powder).

Continue grinding sediment
Transfer about 1 gram of the finely ground sediment into an acid washed and tared 10 dram plastic vial with a snap top.

Write the net weight on the side of the vial.

*This ground portion of the sample can be used for trace metals or CHN analysis although CHN samples are usually ground with a Ball Mill Grinder.
Pour into vial


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