D2622_8 (16)
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Samples shall be
taken in accordance
with the instructions
and practices D4057
or D4177 when applicable.
When reuseable sample
cells are used,
clean and dry cells
before each use.
Disposable sample cells
shall not be reused.
For each sample, an
unused piece of x-ray film
is required for the sample cell.
Avoid touching the inside
of the sample cell,
the portion of the
window film in the cell,
or the instrument window (if
the instrument is so equipped)
that is exposed to x-rays.
Oil from fingerprints
can affect the reading
when analyzing for
low levels of sulfur.
Wrinkles in the film will affect
the intensity of the sulfur
x-rays transmitted.
Therefore, it is essential
that the film be taut and clean
to ensure reliable results.
The analyzer may
need recalibration
if the type or thickness of
the window film is changed.
After the sample cell is
filled, create a small vent hole
except when the cell
is of the sealed type.
Employ adequate storage,
mixing, and sampling procedures.
Refrigerate gasolines or other
similar volatile materials
to retain sample
integrity in storage,
but allow them to return to
room temperature before testing.
Expose these materials to
ambient conditions only
as long as necessary to
obtain a sample for analysis.
Impurities or
thickness variations,
which may affect the measurement
of low levels of sulfur,
have been found
in polyester films
and may vary from lot to lot.
Therefore, the
calibration should
be checked after starting
each new lot of film.
See practice D7343 for more
detailed sample handling
and preparation information.