LaMotte MF 3-0035 - Manual (Page 4)

6. Remove the funnel and lid (A & B) from the apparatus. Use a clean forceps to
place a white, sterile pad (C) on the filter holder section (D) within the circle
guides.
7. Open a sterile membrane filter envelope. Use clean forceps to remove the
membrane filter (E) from the pack. Carefully separate the membrane filter from
the top and bottom protective backings. Do not tear or damage filter.
8. Place the membrane filter, grid side up, on top of the white pad.
9. Replace the funnel and lid on the filter holder section. Push the funnel down onto
the filter holder section until it is fully and evenly seated. This will seal the
connection and hold the membrane filter and white pad firmly in place.
10. Push the plunger (H) all the way into the barrel (I) of the syringe. Then attach the
tubing (J) from the syringe to the adapter (G) on the side of the collection
container (F).
Filter the sample
11. Swirl the water sample container to mix the contents.Remove the apparatus lid
from the funnel. Pour the water sample into the funnel.
If the sample size is less than 10 mL, add 10-20 mL of sterile diluent to the
funnel before attaching the syringe. Then add the sample and swirl the
apparatus gently to mix the sample and the diluent. Attach the syringe.
NOTE: The diluent is used to distribute the sample more evenly over the
surface of the membrane filter during filtration. The amount of diluent should
not be included in the final calculation. Use only the amount of the original
sample size in the calculation.
12. Pull the syringe plunger out, nearly to the end of the barrel, to create a vacuum.
The water sample will be pulled through the membrane filter. Any
microorganisms that are present will be deposited on the surface of the
membrane filter.
NOTE: Larger water samples may not be completely filtered with a single pull of
the plunger. To complete the filtration, carefully remove the tubing and syringe
from the adapter on the side of the filter apparatus. Push the plunger all the way
into the barrel of the syringe. Reattach the tube to the apparatus and pull out the
plunger.
13. When the entire water sample has passed through the membrane filter, remove
the tubing and syringe. Carefully remove the funnel from the apparatus.
14. Use clean forceps to lift the membrane filter from the filter holder section of the
apparatus. Place the membrane filter, grid side up, on top of the pad in a
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