Basic HTML Version
Appendix B
5/20/2009
16
filtered/10
32
Sleeve + filter pad
+ standard
Atropine (1500-
2500ug)
LFB
Weight of
Atropine
33-61
Samples
Volume
filtered/10
62
Capsule + Sleeve
Blank
Blank
0
63
Sleeve + capsule+
standard
Atropine (1500-
2500ug)
LFB
Weight of
Atropine
64
Capsule + Sleeve
Blank
Blank
0
a
Always use STD1 in the Standard position. The system recognizes
this as acetanilide and makes the appropriate calculations for the K
factor.
11.2.3. By entering volume filtered/10 for the weight of the aqueous filtered samples,
results are printed out which represent micrograms of carbon or nitrogen per liter.
This corresponds directly to the known amount of liquid that has passed though
the filter. The maximum sample capacity per run is approximately 4,000 to 5,000
micrograms of carbon on the filter pad. Filters containing more than that amount
can be cut in half and analyzed separately and the results added.
11.2.4. Filter Preparation for Analysis
11.2.4.1.
Work on a clean, non-contaminating surface.
11.2.4.2.
Using two pairs of clean forceps, fold the filter in half so that the
exposed surface is inside. Continue folding the filter in half until you have
a compact package.
11.2.4.3.
Place a pre-combusted 7 x 5 mm nickel sleeve into the filter loading
die, which functions as a holding device. Use the clean 4 mm loading
plunger to force the compressed filter through the clean loading funnel and
into the nickel sleeve.
11.2.4.4.
Make sure no excess filter protrudes above the lip of the sleeve.
11.2.4.5.
Place loaded sleeve in the 64-sample wheel.
11.2.5. Determination of Particulate Organic and Inorganic Carbon
11.2.5.1. Thermal Partitioning is the method used. The difference found
between replicate samples, one part of which has been analyzed for total PC and
PN and the other which was muffled at 550
o
C for three hours to drive off organic
compounds, and analyzed is the particulate organic component of that sample.
This method of thermally partitioning organic and inorganic PC may
underestimate slightly the carbonate minerals’ contribution in the inorganic
fraction since some carbonate minerals decompose below 500
o
C, although CaCO
3
does not. This method is used for filtered samples where at least two filters per
sample must be supplied. For sediment samples at least 1 g of sample is required
and at least 0.5g of sample is weighed into a crucible of known weight. The
weight is recorded. The crucible is then muffled as above, and weighed again.
The percent remaining of the ash is calculated and multiplied times the %C in the
ash which is then determined by the 440.