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AA (AAS): Atomic Absorption Spectrometer instrument used primarily for analysis of metallic elements. There are several AAS instruments available which include the following:

FLAA = Flame (Direct Aspiration) Atomic Absorption Spectroscopy
ICP = Inductively Coupled Plasma
GFAA = Graphite Furnace Atomic Absorption Spectroscopy
GHAA = Gaseous Hydride Atomic Absorption
CVAA = Cold Vapor Atomic Absorption Method

These instruments work by exciting the atom so that it absorbs or emits electromagnetic radiation at a characteristic, identifiable wavelength.

ACCURACY: The nearness of a result, or the mean (X) of a set of results, to the true value. Accuracy is assessed by means of reference samples and percent recoveries.

ACTION LEVEL: California Department of Health Services' health-based criteria for drinking water quality which are recommended, but not enforceable by law.

ALIQUOT: A measured portion of a sample taken for analysis.

ANALYTE: The element, compound, or ion an analysis seeks to determine; the element of interest.

ANALYTICAL BATCH: Samples which are analyzed together with the same method sequence and the same lots of reagents and with the manipulations common to each sample within the same time period or in continuous sequential time periods. Samples in each batch should be of similar matrix.

ANALYTICAL SAMPLE: Any solution or media on which an analysis is performed, excluding instrument calibration, standard runs, initial calibration verification and continuing calibration verification.
Note: The following are all defined as analytical samples: undiluted and diluted samples, predigestion spike samples, duplicate samples, serial dilution samples, analytical spike samples, post-digestion spike samples, interference check samples, laboratory control sample, preparation blank, and linear range analysis sample.

ANALYTICAL SPIKE: The addition of a known amount of standard to a sample before analysis used to determine the efficiency of the analytical equipment.

BACKGROUND CORRECTION: A technique used to compensate for variable background contribution to the instrument signal.

BLANK: A blank is an artificial sample designed to monitor the introduction of artifacts into the process. For aqueous samples, reagent water is used as a blank matrix; however, a universal blank matrix does not exist for solid samples, and therefore, no matrix is used. The blank is taken through the appropriate steps of the process.

Field blanks are aliquots of analyte-free water or solvents brought to the field in sealed containers and transported back to the laboratory with the sample containers. Trip blanks and equipment blanks are two specific types of field blanks.

Trip blanks are not opened in the field. They are a check on sample contamination originating from sample transport, shipping, and from site conditions.

Equipment blanks are opened in the field and the contents are poured appropriately over or through the sample collection device, collected in a sample container, and returned to the laboratory as a sample. Equipment blanks are a check on sampling device cleanliness.

A method blank is an analytical control consisting of all reagents, internal standards and surrogate standards, that is carried through the entire analytical procedure. The method blank is used to define the level of laboratory background contamination. An aqueous method blank is treated with the same reagents as a sample with a water matrix. A solid method blank is treated with the same reagents as a soil sample. A preparation blank is an analytical control that contains distilled, deionized water and reagents, which is carried through the entire analytical procedure (digested and analyzed).

A reagent blank is an aliquot of analyte-free water or solvent analyzed with the analytical batch. This is synonymous with laboratory reagent blank (LRB).

BTEX: Benzene, Toluene, Ethylbenzene, Xylenes; Aromatic hydrocarbons.

BIOACCUMULATION: The concentration of compounds or elements in living tissue.

CAA: Clean Air Act (1955, 1977); federal law mandating and enforcing toxic emissions standards for stationary sources and motor vehicles.

CALIBRATION: The establishment of an analytical curve based on the absorbance, emission intensity, or other measured characteristic of known standards. Calibration standards must be prepared using the analytes of interest and the same type of reagents/chemicals as used in the sample preparation.

CARCINOGEN: A cancer-causing substance.

CCC: Calibration Check Compound

CERCLA: Comprehensive Environmental Responsibility Compensation and Liability Act (1980); also known as Federal Superfund; federal law authorizing identification and remediation of abandoned hazardous waste sites; amended in 1986 by SARA Title III, Section 313 (refer to explanation below).

CHLOROFLUOROCARBON (CFC): Carbon compound(s) with Chlorine and Fluorine attached covalently; a chemical substance associated with the depletion of Earth's ozone layer.

CHAIN-OF-CUSTODY: A document used to trace the movement and custody of a sample from the actual sample collection to final analysis and storage. See sample in Chapter 1, Section 1.5 of this manual.

CHARACTERIZATION: A determination of the approximate concentration range of compounds of interest used to choose the appropriate analytical protocol.

CIS: Isomer which has the same chemical formula as the trans compound but has a different arrangement of its atoms in 3-dimensional space.

CLP: EPA Contract Laboratory Program

COEFFICIENT OF VARIATION (CV): The standard deviation as a percent of the arithmetic mean.

CONTROL LIMITS: A range within which specified measurement results must fall into to be compliant. Control limits may be mandatory, requiring corrective action if exceeded, or advisory, requiring that non-compliant data be flagged.

CORRELATION COEFFICIENT: A number (r) which indicates the degree of dependence between two variables (for example, concentration - absorbance). The more dependent they are the closer the value to one. Determined on the basis of the line drawn by the least squares line fitting method.

CORROSIVE: A material that causes the destruction of metals and alloys by chemical reaction (mainly oxidation).

CWA: Clean Water Act of 1972; federal law regulating the discharge of pollutants into surface waters.


DHS: Department of Health Services

DISCRETE: Distinct or separate samples.

DRY WEIGHT: The weight after drying in an oven at 105oC for 24 hours.

DUPLICATE: Two aliquots of the same sample taken in the analytical laboratory and analyzed separately with identical procedures. Both aliquots give a measure of the precision associated with sample collection, preservation and storage, as well as with laboratory procedures.

EPA: U. S. Environmental Protection Agency

FIELD SAMPLE: A representative sample of any material (aqueous, non-aqueous, or multimedia) collected from any source for which determination of composition or contamination is required.

FIELD DUPLICATE: Two separate samples collected at exactly the same time and place under identical circumstances and treated exactly the same throughout field and laboratory procedures. These samples give a measure of the precision associated with sample collection, preservation and storage, as well as with laboratory procedures.

GC: Gas Chromatograph. Instrument used in the environmental field for the analysis of organic compounds. The instrument is typically used as a means to separate a multicomponent mixture into the individual compounds which are then analyzed by a detector as listed below:

ECD = Electron Capture Detector

ELCD = Electrolytic Conductivity Detector

ECMD = Electrochemical Detector

FID = Flame Ionization Detector

FL = Flourescence (emission)

FPD = Flame Photometric Detector

MS = Mass Spectrometer

NPD = Nitrogen-Phosphorus Detector

PID = Photoionization Detector

UV = Ultraviolet (absorbance)

GC/MS: Gas Chromatography/Mass Spectrometry; Gas Chromatography separation technique which uses a Mass Spectrometer for the detection device.

HAZARDOUS WASTE: Any waste or combination of wastes which pose a substantial present or potential hazard to human health or living organisms because such wastes are non-degradable or persistent in nature or because they can be biologically magnified, or because they can be lethal, or because they may otherwise cause or tend to cause detrimental cumulative effects. (from 40 CFR, §240.101)

HOLDING TIME: The allowable elapsed time expressed in days from the date of sample collection until the date of its analysis.

HPLC: High Pressure Liquid Chromatograph; Instrument used in the environmental field for the analysis of organic compounds. The instrument is typically used as a means to separate the different compounds which are then analyzed by a detector as listed in the explanation of the term GC.

HSWA: Federal Hazardous and Solid Waste Amendments

INDUCTIVELY COUPLED PLASMA (ICP): A technique for the simultaneous or sequential multi-element determination of elements in solution. The basis of the method is the measurement of atomic emission by an optical spectroscopic technique. Characteristic atomic line emission spectra are produced by excitation of the sample in a radio frequency inductively coupled plasma.

IN-HOUSE: The analyses are run on the premises of the laboratory facility.

INDEPENDENT STANDARD: A Contractor-prepared standard solution that is composed of analytes from a different source than those used in the standards for the initial calibration.

INSTRUMENT CALIBRATION: Analysis of analytical standards for a series of different specified concentrations; used to define the quantitative response, linearity, and dynamic range of the instrument detector to target analytes.

INTERFERANTS: Substances which affect the analysis of the element or compound of interest.

INTERNAL STANDARDS: A pure analyte(s) added to a solution in known amount(s) and used to measure the relative responses of other method analytes that are components of the same solution. The internal standard must be an analyte that is not a sample component.

IR: Infrared Spectrometer; in environmental analysis, used primarily for the detection and quantitation of hydrocarbons.

LABORATORY: A facility which runs analyses for elements, organic compounds, or other analytes using EPA approved methods as well as quality assurance quality control procedures.

LABORATORY CONTROL SAMPLE: A control sample of known composition. Aqueous and solid laboratory control samples are analyzed using the same sample preparation, reagents, and analytical methods employed for the EPA samples received.

LABORATORY PERFORMANCE CHECK SOLUTION (LPC): A solution of one or more compounds used to evaluate the performance of the instrument system with respect to a defined set of method criteria.

LINEAR RANGE, LINEAR DYNAMIC RANGE: The concentration range over which the analytical curve remains linear.

MATRIX: The predominant material of which the sample to be analyzed is composed. A sample matrix is either water or soil/sediment. Matrix is not synonymous with phase (liquid or solid).

MATRIX MODIFIER: Salts used in Atomic Absorption to lessen the effects of chemical interferants, viscosity, and surface tension.

MATRIX SPIKE: Aliquot of a sample (water or soil) fortified (spiked) with known quantities of specific compounds and subjected to the entire analytical procedure in order to indicate the appropriateness of the method for the matrix by measuring recovery.

METHOD: An established procedure for analyses of an element, compound or other analyte.

METHOD OF STANDARD ADDITIONS (MSA): The addition of three increments of a standard solution (spikes) to sample aliquots of the same size. Measurements are made on the original and after each addition. The slope, x-intercept and y-intercept are determined by least-square analysis. The analyte concentration is determined by the absolute value of the x-intercept. Ideally, the spike volume is low relative to the sample volume (approximately 10% of the volume). Standard addition may counteract matrix effects; it will not counteract spectral effects. Also referred to as Standard Addition.

MQL: The method quantification limit (MQL) is the minimum concentration of a substance that can be measured quantitatively and reported.

MSDS: Material safety data sheet; contains descriptive information on hazardous chemicals under OSHA's Hazard Communication Standard (HCS).

NARRATIVE (Case Narrative): Portion of the data package which includes laboratory, contract, case and sample number identification, and descriptive documentation of any problems encountered in processing the samples, along with corrective action taken and problem resolution.

ND: Not detected.

OSHA: Occupational Safety and Health Administration

PCB: Polychlorinated biphenyl; a pathogenic and teratogenic industrial compound used as a heat-transfer agent; PCBs may accumulate in human or animal tissue.

PCE: Perchloroethene, Tetrachloroethene, Tetrachloroethylene (These are different names for the same compound.)

PERCENT MOISTURE: An approximation of the amount of water in a soil/sediment sample made by drying an aliquot of the sample at 105°C. The percent moisture determined in this manner also includes contributions from all compounds that may volatilize at 105°C, including water. Percent moisture is determined from decanted samples and from samples that are not decanted.

PERFORMANCE EVALUATION (PE) SAMPLE: A sample of known composition provided by the EPA for analysis by a laboratory. Used by the EPA to evaluate laboratory performance.

PERSISTENT: Continuing in the face of opposition; continuing to exist of endure; lasting without change.

pH: Negative log of the Hydrogen Ion concentration. Acidic solutions are of pH<7, and Basic solutions are of pH>7.

PPB: Parts per billion - mg/Kg; or µg/liter in some cases.

PPM: Parts per million - mg/Kg; or mg/liter in some cases.

PQL: The practical quantitation limit (PQL) is the lowest level that can be reliably achieved within specified limits of precision and accuracy during routine laboratory operating conditions.

PRECISION: The measurement of agreement of a set of replicate results among themselves without assumption of any prior information as to the true result. Precision is assessed by means of duplicate/replicate sample analysis.

PRIMARY ANALYSIS: One of two types of analyses, the other being the Confirmation Analysis. If the two analyses are run at separate times, the Primary Analysis is the first analysis chronologically, and is used to establish the tentative identification of any compounds detected. The identification is then confirmed in the confirmation analysis. If the two analyses are simultaneous, either may be considered the Primary Analysis.

PROPOSITION 65: California's Safe Drinking Water and Toxic Enforcement Act of 1986

PROTOCOL: Describes the exact procedures to be followed with respect to sample receipt and handling, analytical methods, data reporting and deliverables, and document control.

PURGE AND TRAP: Analytical technique used to isolate and concentrate volatile (purgeable) organics by stripping the compounds from water or soil into a stream of inert gas, trapping the compounds from the inert gas on a porous trap, and thermally desorbing the trapped compounds onto the gas chromatographic column.

QA: Quality Assurance - System for monitoring and maintaining quality control.

QC: Quality Control - System for maintaining desired standards of quality in analysis.

RCRA: Resource Conservation and Recovery Act (1976); regulates management and disposal of hazardous materials and wastes being generated, treated, stored, disposed, or distributed; amended in 1984 by HSWA.

REAGENT GRADE: Analytical reagent (AR) grade, ACS reagent grade, and reagent grade are synonymous terms for reagents which conform to the current specifications of the Committee on Analytical Reagents of the American Chemical Society. REAGENT WATER: Distilled or deionized water or Type II reagent water which is free of contaminants that may interfere with the analytical test in question. Synonymous with analyte-free or laboratory pure water.

RECOVERY: A determination of the accuracy of the analytical procedure made by comparing measured values for a fortified (spiked) sample against the known spike values.

RELATIVE RESPONSE FACTOR (RRF): A measure of the relative response of an analyte compared to its internal standard. Relative Response Factors are determined by analysis of standards and are used in the calculation of concentrations of analytes in samples.

REPLICATE SAMPLE: A sample prepared by dividing a sample into two or more separate aliquots. Duplicate samples are considered to be two replicates.

RESOLUTION: Also termed separation, the separation between peaks on a chromatogram. Calculated by dividing the height of the valley between the peaks, by the peak height of the smaller peak being resolved, multiplied by 100.

RUN: A continuous analytical sequence consisting of prepared samples and all associated quality assurance measurements.

SAMPLE: A portion of material to be analyzed that is contained in single or multiple containers and identified by a unique sample number.

SARA TITLE III - SECTION 313: Superfund Amendments and Reauthorization Act (1986); federal law reauthorizing and expanding the jurisdiction of CERCLA.

SEMIVOLATILE COMPOUNDS: Compounds amenable to analysis by extraction of the sample with an organic solvent. Used synonymously with Base/Neutral/Acid (BNA) compounds.

SERIAL DILUTION: The dilution of a sample by a know factor. When corrected by the dilution factor, the diluted sample must agree with the original undiluted sample within specified limits. Serial dilution may reflect the influence of interferants.

SOIL: the top layer of the earth's surface, composed of rock and mineral particles mixed with animal and vegetable matter; dirt.

STANDARD ANALYSIS: An analytical determination made with known quantities of target compounds; used to determine response factors.

STANDARD CURVE: A curve which plots concentrations of known analyte standard versus the instrument response to the analyte.

STLC: Soluble Threshold Limit Concentration. California Code of Regulations, Title 22 - regulatory standard for hazardous waste. The WET extraction method is employed to determine the soluble fraction of the components of interest.

STOCK SOLUTION: A concentrated standard solution which can be diluted to derive other standards.


SURROGATES: A compound which is not a target analyte for the method in question, and which is added to a sample aliquot in known amount(s) before extraction and is measured with the same procedures used to measure other sample components. The purpose of a surrogate analyte is to monitor method performance with each sample.

SYSTEM PERFORMANCE CHECK COMPOUNDS (SPCC): Target compounds designated to monitor chromatographic performance, sensitivity, and compound instability or degradation on active sites. Minimum response factor criteria for the SPCCs are defined in the method procedure.

TARGET COMPOUND LIST (TCL): A list of compounds designated for analyses under a specific method.

TCA: 1,1,1-Trichloroethane or 1,1,2-Trichloroethane, a volatile halocarbon.

TCE: Trichloroethene (Trichloroethylene).

TOXIC: Poisonous

TPH: Total Petroleum Hydrocarbons: Low to high boiling point hydrocarbons, including gasoline, kerosene, diesel fuels, thinners, bunker fuels, jet fuels, and oils; determined by EPA Methods 8015M or 418.1.

TRANS: Isomer which has the same chemical formula as the cis compound but has a different arrangement of atoms in space.

TTLC: Total Threshold Limit Concentration. California Code of Regulations, Title 22 - regulatory standards for hazardous waste before subjection to STLC.

UST: Underground storage tank; regulated by RCRA; tank with 10 or more percent of its volume underground, with connected piping; used to store CERCLA-regulated hazardous chemicals or petroleum products.

VOLATILE COMPOUNDS (VOC): Compounds amenable to analysis by the purge and trap technique. Used synonymously with purgeable compounds. Organic material used in industrial applications (such as paints and solvents) that evaporate quickly.

WET: Waste Extraction Test. California extraction procedure used to extract compounds for analysis and comparison with STLCs.

WET WEIGHT: The weight of a sample aliquot including moisture (not a dried sample).

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