D4629_11 (17) 02-2018
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Obtain a test specimen
using the procedure
in section 8 of the
written standard.
The nitrogen concentration
in the test specimen
must be less than the
concentration of the highest
standard used in
the calibration.
Injection volumes ranging from
3 microliters to 100 microliters
are acceptable, depending on
the instrument being used.
The size of the
injected sample shall
be similar to the size of
the injected standards used
for calibration.
Flush a clean microliter
syringe several times
with a sample to be
determined, and introduce it
into the furnace
using the procedure
outlined in 10.2 through
10.4 of the written standard,
depending on whether a boat
inlet system is being used.
For samples with total nitrogen
concentration in the range 1
milligrams per kilogram to
100 milligrams per kilogram,
sample sizes injected are
typically up to 10 microliters.
For samples with total
nitrogen concentration
less than 1 milligram
per kilogram,
injected sample size can
be up to 100 microliters.
Follow the instrument
manufacturer's recommendation
on sample size based on type
of sample and level of nitrogen
present.
To obtain one result,
measure each test specimen
a minimum of three times and
calculate the average detector
response.