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Appendix A
5/20/2009
4
3.23
Laboratory Control Sample (LCS) – A sample matrix, free from the
analytes of interest, spiked with verified known amounts of analytes
from a source independent of the calibration standard or a material
containing know and verified amounts of analytes. The LCS is
generally used to establish intra-laboratory or analyst-specific precision
and bias or to assess the performance of all or a portion of the
measurement system. (NELAC)
3.24
Limit of Detection (LOD) – The lowest concentration level that can be
determined by a single analysis and with a defined level of confidence to
be statistically different from a blank. (ACS)
3.25
Limit of Quantitation (LOQ) – The minimum levels, concentrations, or
quantities of a target variable (target analyte) that can be reported with a
specified degree of confidence. The LOQ is set at 3 to 10 times the
LOD, depending on the degree of confidence desired.
3.26
Linear Dynamic Range (LDR) – The absolute quantity over which the
instrument response to an analyte is linear. This specification is also
referred to as the Linear Calibration Range (LCR).
3.27
Material Safety Data Sheets (MSDS) – Written information provided by
vendors concerning a chemical’s toxicity, health hazards, physical
properties, fire, and reactivity data including storage, spill, and handling
precautions.
3.28
May – Denotes permitted action, but not required action. (NELAC)
3.29
Method Detection Limit (MDL) – The minimum concentration of an
analyte that can be identified, measured, and reported with 98%
confidence that the analyte concentration is greater than zero.
3.30
Must – Denotes a requirement that must be met. (Random House
College Dictionary)
3.31
Precision – The degree to which a set of observations or measurements
of the same property, obtained under similar conditions, conform to
themselves; a data quality indicator. Precision is usually expressed as
standard deviation, variance or range, in either absolute or relative terms.
(NELAC)
3.32
Preservation – Refrigeration, freezing, and/or reagents added at the time
of sample collection (or later) to maintain the chemical and or biological
integrity of the sample.
3.33
Quality Control Sample (QCS) – A sample of analytes of known and
certified concentrations. The QCS is obtained from a source external to
the laboratory and different from the source of calibration standards. It
is used to check laboratory performance with externally prepared test
materials.
3.34
Run – One sample analysis from start to finish, including printout.
3.35
Run Cycle – Typically a day of operation – the entire analytical
sequence of runs from the first run to the last run and including the
transfer of run cycle data to the disc.
3.36
Sample Volume – Amount of volume filtered.