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Appendix B
5/20/2009
2
the original sample. A similar measurement is made of the signal output of a second
pair of thermal conductivity cells, between which a trap removes carbon dioxide,
thus determining the carbon content. The remaining gas now consists only of helium
and nitrogen. This gas passes through a thermal conductivity cell and the output
signal is compared to a reference cell through which pure helium flows. This gives
the nitrogen concentration.
Schematic diagram of
the Exeter Analytical,
Inc.
(EAI) CE‐440 Elemental Analyzer
3.
DEFINITIONS
3.1.
Acceptance Criteria
-
Specified limits placed on characteristics of an item, process,
or service defined in a requirement document. (ASQC)
3.2.
Accuracy -
The degree of agreement between an observed value and an accepted
reference value. Accuracy includes a combination of random error (precision) and
systematic error (bias) components which are due to sampling and analytical
operations; a data quality indicator. (QAMS)
3.3.
Acetanilide
- Used as a standard or conditioner in the analyzer for calibration
purposes. It has known percentages of C, H, and N.
3.4.
Aliquot -
A discrete, measured, representative portion of a sample taken for analysis.
(
EPA QAD Glossary
)
3.5.
Batch -
Environmental samples, which are prepared and/or analyzed together with
the same process and the same personnel using the same lot(s) of reagents. A