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Lead
5.
When the timer
beeps, use a second 1-mL
plastic dropper to add
2.0 mL of pPb-2 Fixer
Solution. Swirl to mix.
Note: Field samples that have
been preserved with nitric acid
or samples that have been
digested may exceed the buffer
capacity of the Fixer Solution.
After step 5, check the pH of
these samples and adjust with
5 N Sodium Hydroxide to a pH
of 6.7–7.1 before proceeding
with step 6.
9.
After the flow has
stopped, fully compress
the absorbent pad in the
Extractor with the
plunger. Discard the
contents of the beaker.
Slowly withdraw the
plunger from the
Extractor.
Note: The absorbent pad
should remain at the bottom of
the Extractor when the plunger
is removed. If the cotton plug
moves up the column, push it
back to the bottom with a clean,
blunt rod.
Lead
Page 2 of 8
6.
Mount a new Fast
Column Extractor in a
ring stand with a clamp.
Place a 150-mL plastic
beaker under the
Extractor.
A Fast Column Extractor
is included in the
®
LeadTrak
Reagent Set.
A new extractor is
required for each test.
10.
Place a clean, dry
25-mL sample cell under
the Extractor. Using a
25-mL plastic graduated
cylinder, add 25 mL of
pPb-3 Eluant Solution to
the Extractor.
Keep the level of the
eluent solution just above
the absorbent pad.
7.
Soak the cotton plug
with deionized water and
compress it with the
plunger. Remove the
plunger. If the cotton
plug moves up the
column, push it back to
the bottom with a clean,
blunt rod.
The cotton plug should fit
snugly against the inner
wall of the column.
11.
Allow the Eluant
Solution to drip slowly
from the Extractor.
After the flow has
stopped, fully compress
the absorbent pad. The
volume in the sample cell
should be 25 mL.
8.
Pour the prepared
sample slowly into the
center of the Column
Extractor. Wait for the
sample to flow through.
The sample solution
should flow relatively
slowly (2 drops per
second) through the
column.
Keep the level of the
sample solution just above
the cotton plug.
25 mL
20 mL
10 mL
12.
Using a 1-mL plastic
dropper, add 1.0 mL of
pPb-4 Neutralizer
Solution to the cell. Swirl
thoroughly to mix and
proceed immediately to
step 13.
Lead_None_Other_LTK_Eng_Ody.fm
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