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Appendix B
5/20/2009
14
Acetanilide C = 71.09% H = 6.71% N = 10.36%
If another standard is used, the values will need to be entered into the computer
using The Edit Standards function in the Customizing Menu.
10.3.1. Once the blank values have been established and entered into memory, proceed
to run known standards to arrive at the calibration factors for carbon and nitrogen
for the instrument.
10.3.2. Run a minimum of three standards, average the results, and enter into computer
memory, or use the automatic enter mode. During the run, standards may be
entered as samples to verify the K-factors and blanks.
10.3.3. Any time a STD1 is entered as sample ID the computer calculates and enters a
new set of operating Ks based on a weighted formula using the last three sets of
Ks in memory. This occurs only if all three Ks fall within the following windows:
New KC = KC in memory ± 1.0
KN = KN in memory ± 0.5
10.3.3.1.
It is important that the Ks in memory be close to expected values or
new Ks generated will not be within the window and therefore will not be
accepted for automatic insertion.
10.3.3.2.
The weighted formula for calculating the Ks:
where:
k
1
= k found in this run
k
2
= Next k in memory
k
3
= Last k in memory
10.4.
Conditioner
- Before running any samples or blanks, it is necessary to run
one or more conditioners. The purpose of the conditioner runs is to coat the walls of
the system surfaces, especially the mixing and sample volume, with water vapor,
carbon dioxide and nitrogen which simulates actual sample running conditions. To
simulate this condition as closely as possible, it is advisable to use conditioners of
approximately the same weight as the samples to the run.
10.5.
Blanks
- The blank values used in the calculation is the total signal generated
by the system including the ladle and sample capsule. This blank should always be
run immediately after a weighed conditioner to represent a true blank of the
instrument. Never use the blank value after an empty run since the system dries up
and the blank value would be lower than normal.
10.5.1. The blanks will only be accepted if they fall within the following:
New BC < 500
New BN < 250
10.6.
K-Factors
- Once the blank values have been established and entered into
memory, proceed to run known standards in order to establish the calibration factors
for carbon, hydrogen and nitrogen. Always run a conditioner before a standard. The
computer will calculate K-factors as long as STD# has been entered as the sample
ID. Run a minimum of three (3) standards, average the results, and enter into the