Branch of Quality Systems


 

Glossary

The Branch of Quality Systems (BQS) operates an Organic Blind Sample Project (OBSP). One of the goals of the project is to document bias and variability for the National Water Quality Laboratory (NWQL) through the use of blind quality assurance (QA) samples.

The OBSP has compiled a glossary of terms that are used in the OBSP Summaries (Internal access only)

B N A - Base neutral acid
B T M - Bottom material
B Q S - Branch of Quality Systems
CARB - Carbon
CAS # - CAS Registry NumberŪ is a Registered Trademark of the American Chemical Society. CAS recommends the verification of the CASRNs through CAS Client Services.
C C V - Continuing Calibration Verification Standard - A standard solution used in instrumental analysis to check instrument stability in relation to the calibration standard curve. Prepared from the same materials in the same manner as the calibration standards. Concentration of the CCV should be chosen to allow easy review by the analyst and is typically in the midrange of the calibration curve.
C R M - Certified Reference Material - A reference material one or more of whose property values are certified by a technically valid procedure, accompanied by or traceable to a certificate or other documentation that is issued by a certifying body (National Environmental Laboratory Accreditation Conference, 2003b)
D B C P - Dibromochloropropane
DIS - Dissolved, Pertains to the constituents in a representative water sample that pass through a 0.45-micrometer membrane filter for inorganic analysis or a 0.7-micrometer glass fiber filter for organic analysis. This is a convenient operational definition used by Federal agencies that collect water data. Determinations of "dissolved" constituents are made on sub-samples of the filtrate.
D W - Drinking water
E D B - 1,2-Dibromoethane
E P A - Environmental Protection Agency
False negative - (also called type II error or beta error) - A statement that a substance is not present (was not found) in a sample when the substance was present (Keith, 1992).
False positive - (also called type I error or alpha error) - A statement that a substance is present in a sample when it is not (Keith, 1992).
FIL - Filtered (in the past known as dissolved (DIS)), Pertains to the constituents in a representative water sample that pass through a 0.45-micrometer membrane filter for inorganic analysis or a 0.7-micrometer glass fiber filter for organic analysis. This is a convenient operational definition used by Federal agencies that collect water data. Determinations of "dissolved" constituents are made on sub-samples of the filtrate.
G C - Gas chromatography
G C / E C D - Gas chromatography/electron capture detector
G C / F I D - Gas chromatography/flame ionization detector
G C/ F P D - Gas chromatography/flame photometric detector
G C / M S - Gas chromatography/Mass Spectrometry
G C / M S / S I M - Gas chromatography/Mass Spectrometry/selected ion monitoring
G C / N P D - Gas chromatography/Nitrogen Phosphorous detector
H P L C - High-performance liquid chromatography
Information-rich methods - Classified as organic methods that use either mass spectrometric or photodiode array ultraviolet/visible spectroscopic detection. These methods have additional qualifying information that allows enhanced analyte identification.
IRL - Interim Reporting Level
L C - Lab Code
L T - M D L - Long Term Method Detection Level - A detection level derived by determining the standard deviation of a minimum of 24 MDL spike sample measurements over an extended period of time. LT-MDL data are collected on a continuous basis to assess year-to-year variations in the LT-MDL. The LT-MDL controls false positive error. The chance of falsely reporting a concentration at or greater than the LT-MDL for a sample that did not contain the analyte is predicted to be less than or equal to 1 percent.
L M S - Laboratory Matrix Spike - Environmental sample fortified in the lab with known concentrations of organic compounds
L R L - Laboratory Reporting Level - Generally equal to twice the yearly determined L T - M D L. The LRL controls false negative error. The probability of falsely reporting a non-detection for a sample that contained an analyte at a concentration equal to or greater that the LRL is predicted to be less than or equal to 1 percent. The value of the LRL will be reported with a "less than" remark code for samples in which the analyte was not detected. The National Water Quality Laboratory collects quality-control data from selected analytical methods on a continuing basis to determine long-term method detection levels (LT-MDL's) and establish laboratory reporting levels (LRL's). These values are re-evaluated annually based on the most current quality-control data and may, therefore, change. [Note: In several previous NWQL documents (Connor and others, 1998; NWQL Technical Memorandum 98.07, 1998), the LRL was called the non-detection value or NDV - a term that is no longer used.]
L R B - Laboratory Reagent Blank (also known as a set blank) - Sample of organic-free matrix undergoing the sample preparation steps in the lab
L R S - Laboratory Reagent Spike (also known as a set spike) - Sample of organic-free matrix undergoing the sample preparation steps in the lab
L S - Laboratory Schedule
L S D - Least Significant Digit - The first real number (nonzero) to the right of the decimal point in the standard deviation of the LT-MDL spike samples.
M D L - Method detection limit - Minimum concentration of a substance that can be measured and reported with 99-percent confidence that the analyte concentration is greater than zero. It is determined from the analysis of a sample in a given matrix containing the analyte (U.S. Environmental Protection Agency, 1997). At the MDL concentration, the risk of a false positive is predicted to be less than or equal to 1 percent.
m g / L - milligram per liter
Method Blank Sample of organic-free matrix undergoing the sample preparation steps in the lab
M R L - Minimum reporting level - Smallest measured concentration of a constituent that may be reliably reported by using a given analytical method (Timme, 1995).
N A - Not applicable.
N A W Q A - National Water-Quality Assessment Program.
Non-quantitative result - Unable to report a concentration. Either not detected or detected in a region of high uncertainty (high probability of false positive) and outside the calibration range.
N W Q L - National Water Quality Laboratory
O B S P - Organic Blind Sample Project
P C B - Polychlorinated Biphenyls
P C N - Polychlorinated Naphthalene
Quantitative result - Concentration reported. Value is within range of instrument calibration and, thus, of higher certainty.
Reagent Blank (also known as a set blank) - Sample of organic-free matrix undergoing the sample preparation steps in the lab
Reagent Spike (also known as a set spike) - Sample of organic-free matrix fortified in the lab with known concentrations of organic compounds
Replicate Sample - Environmental sample split into tow or more aliquots
R L - Reporting level - A generic term for LRL, MRL, or IRL
Semi-quantitative result - Estimated concentration reported because it is outside the calibration range.
S P E - Solid phase extraction
S R M - Standard Reference Material
S R S - Standard Reference Sample - A sample that is prepared to check and monitor inorganic
Surrogate compounds - Organic compounds similar in physical and chemical properties to analytes but not present in samples
T C E - trichloroethene
T H M - trihalomethane
T P C - Third Party Check: A standard solution used in instrumental analyses to verify the identities and quantities of the target compounds in a calibration standard. A TPC standard is typically acquired from a different source (if possible) than that used to prepare the calibration standard solutions. TPC standards are usually analyzed when an instrument is recalibrated. If results of the TPC analysis fail to meet the acceptance criteria, then the calibration and TPC standards are further evaluated to determine whether new standards should be prepared, or other corrective action is necessary.
T O T - Total
u g / L - microgram per liter
U S G S - U.S. Geological Survey
V O C - Volatile Organic Compound
V O I - Volatile on Ignition
W W R - Whole water, recoverable.
W Y - Water Year

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