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Glossary


EVISA is providing a list of terms used in the area of speciation and fractionation analysis. Since speciation analysis is a field of analytical chemistry that is specified by a pronounced interdisciplinary cooperation between different sciences such as biochemistry, medicine, biology, environmental sciences, nutritional sciences and material sciences its terminology is a complex mixture of terms used in all these.

You may search for a term or browse the glossary alphabetically.

(In case that you cannot find the term you may consult more special glossaries or handbooks about nomenclature. For more details please consult EVISA's List of Glossaries)





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background
in spectroscopy: Data value in a datastream in the absence of any analyte or interference.

background concentration
The concentration (or level) of a substance characteristic of a particular medium (e.g. soil, water, rock etc.) in an area or region arising from both natural sources and non-natural diffuse sources such as atmospheric deposition. (after definition for background concentration soil, ISO 11074-1:1996)

background level(s)
Levels of chemical or physical agents that are normally found in the environment. Two types of background levels may exist for chemical substances or physical agents: (a) Naturally occurring levels: ambient concentrations of substances or agents present in the environment, without human influence; (b) Anthropogenic levels: Concentrations of substances or agents present in the environment due to human-made, non-site sources (e.g., automobiles, industries).

(Source: US EPA Glossary of IRIS Terms )

background mass spectrum
The mass spectrum observed when no sample is intentionally introduced into the mass spectrometer or spectrograph.

Source: IUPAC

bakeout
The process of removing contaminants from a column by operation at elevated temperatures, which should not exceed a column’s maximum operating temperature (MAOT).

band broadening
The process of  increasing width and concomitant diluting  of the chromatographic band as it moves  down the column. The peak is injected as a  narrow slug and, ideally, each separated  component would be eluted as a narrow  slug of pure compound if not for the  process of band broadening. The measure of band broadening is bandwidth (tw) or,  more correctly, the number of theoretical  plates (N) in the column. Sometimes  called band dispersion or band spreading. 

base peak
The base peak in a mass spectrum (within the user-selected mass range) is the ion with the highest measured abundance. The relative abundance of the base  peak ion is assigned a value of 100, and the abundances of all the other ions plotted in that mass spectrum are normalized  to that value. The y-axis in a mass spectrum is therefore given in terms of relative abundance.

batch leaching
A leaching test that estimates how readily contaminants could mobilize out of a solid waste or other solid material if the material comes into contact with natural waters. The test involves placing a given mass of the solid sample in a container with a specific volume of a liquid leaching solution. The leaching solution may be water, salt buffers, acidic solutions, basic solutions, or organic solvents. The mixture is agitated for a specific amount of time (usually, hours to days). Afterwards, the mixture is filtered and the liquid (the leachate) is analyzed for contaminants, such as arsenic. A common batch leaching method is the US Environmental Protection Agency’s toxicity characteristic leaching procedure (TCLP), which is used to determine whether a solid or liquid waste has the toxicity characteristic of hazardousness (compare with leaching, leaching test, column leaching, sequential batch leaching, and serial batch leaching).

BCR extraction schemes
consensus sequential extraction schemes on the basis of sequential solubility of metals bound to a substrate making up sediments and soils. This approach is necessary to ensure comparability of the data corresponding to operationally defined parameters.

benchtop
A term used to distinguish between laboratory-scale or small-scale processes, those that can be performed "on the bench" (in the lab or even on a tabletop) and larger, pilot- or production-scale processes. Benchtop equipment (a "benchtop bioreactor", for example) can fot on a table or in a confined laboratory area.

beneficial metal
Non-essential metal which in some form (chemical species) at an appropriate dose can improve health of defined organisms, commonly human beings.

Berner impactor
Ther Berner impactor is a 8-stage cascade impactor widely used in recent aerosol studies in Europe and in the USA. The flow rate is 1.9 m3h-1 at 20°C with an exhaust pressure of 150 hPa. The impactor consists of eight stages with cut-off diameters of 8/4/2/1/0.5/0.25/0.125/0.0625 µm and a prestage excluding particles > 16 µm.

berylliosis
Serious and usually permanent lung damage resulting from chronic inhalation of beryllium. (IUPAC)

beryllium
a hard brittle, gray-white metal. Resistant to oxidation at ordinary temperatures. Used in computer parts, x-ray tubes, gyroscopes and rocket fuel additive.
Hazard: Highly toxic, especially by inhalation of dust. Long term exposure may cause weight loss, weakness, cough, extreme difficulty in breathing and cardiac failure.

bias
A systematic difference or systematic error between an observed value and some measure of the truth. Generally used to describe the inaccuracy of a method relative to a comparative method in a method comparison experiment. It also has a specific meaning in the statistical t-test, where bias equals the difference between the mean values of the two methods being compared or the average of all the differences between the paired sample values.

binding site
A specific region (or atom) in a molecular entity that is capable of entering into a stabilizing interaction with another molecular entity. An example of such an interaction is that of an active site in an enzyme with its substrate. Typical forms of interaction are by hydrogen bonding, coordination, and ion pair formation. Two binding sites in different molecular entities are said to be complementary if their interaction is stabilizing.

bioaccessibility
Bioaccessibility is a measure of the physiological solubility of a metal in the gut. Because solubility is usually required for absorption across membranes bioaccessibility may be a predictor of bioavailability when solubility is the major determinant of absorption across the gut epithelium.

bioaccumulation
Process by which some endogenous or exogenous substances, present in small quantities, increase in concentration in an organ, an organism, a food chain, or an ecosystem.

(Translated from Parent, S. Dictionnaire des sciences de l'environnement. Broquet, Québec, 1990.)


bioaccumulation factors (BAF)

Ratio of tissue concentration to concentration in medium, with exposure from the food web and the medium.


bioanalytical
Analytical methods that pertain to biotechnology (that is, to proteins, peptides, and other biomolecules) are more specifically referred to as bioanalytical methods.

bioassay
Procedure for estimating the concentration or biological activity of a substance (e.g.vitamin, hormone, plant growth factor, antibiotic, enzyme) by measuring its effect on a living system compared to a standard system.

bioavailability
extent to which a substance to which a body is exposed (by ingestion, inhalation, injection, or skin contact) reaches the systemic circulation, and the rate at which this occurs

biochemical (biological) oxygen demand (BOD)
Substance concentration of oxygen taken up through the respiratory activity of micro-organisms growing on organic compounds present when incubated at a specified temperature (usually 20° C) for a fixed period (usually 5 days). It is regarded as a measure of that organic pollution of water which can be degraded biologically but includes the oxidation of inorganic material such as sulfide and iron(II). The empirical test used in the laboratory to determine BOD also measures the oxygen used to oxidize reduced forms of Nitrogen unless their oxidation is prevented by an inhibitor such as allyl thiourea.

bioconcentration factor (BCF)
The bioconcentration factor (BCF) is a measure of the tendency for a substance in water to accumulate in organisms, especially fish. The equilibrium concentration of a substance in fish can be estimated by multiplying its concentration in the surrounding water by its bioconcentration factor in fish. This parameter is an important parameter characterizing the food-chain and a determinant for human intake of aquatic food by the ingestion route.

bioconcentration factors (BCF)
Ratio of tissue concentration to concentration in medium, with exposure only through the medium.

bioconversion
Synonym for biotransformation

biodegradability
The ability of a substance to be broken down into simpler substances by biological organisms such as bacteria or fungi or other natural physical processes (such as sunlight).

biodegradation
Breakdown of a substance catalyzed by enzymes in vitro or in vivo. In ecotoxicology, it is almost en-
tirely due to microbial or fungal activity.
Note 1:    Biodegradation  may  be  classified  for  purposes  of  hazard assessment into  three  cate-
gories:
  1. Primary. Alteration of the chemical structure of a substance resulting in loss of a specific property of that substance.
  2. Environmentally acceptable. Biodegradation to such an extent as to remove unde-sirable properties of the compound. This often corresponds to primary biodegradation but depends on the circumstances under which the products are discharged into the environment.
  3. Ultimate. Complete breakdown of a compound to either fully oxidized or reduced simple molecules (such as carbon dioxide, methane, nitrate, ammonium, and (or) water).
Note 2:    The products of biodegradation can be more harmful than the substance that was de-
graded.

biogeochemical cycle
Movement of elements or molecules among organisms and nonliving compartments of the atmosphere,
lithosphere, and hydrosphere.
Note 1:    Examples of biogeochemical cycles are the carbon, nitrogen, phosphorus, and sulfur cycles. These are defined as the global flow of C, N, P, and S atoms, respectively, from plants through animals to the atmosphere, soil, water, and back to plants.
Note 2:    The  water  cycle  refers  to  the  global  flow  of  water  from  surface  and  ground  water sources to soil, plants, animals, and the atmosphere, and back to soil and surface water.

bioindicator
A bioindicator (also biological indicator) is a measure, an index of measures, or a model that characterizes an ecosystem or one of its critical components. It may reflect biological, chemical or physical attributes of ecological condition. The primary uses of an indicator are to characterize current status and to track or predict significant change. With a foundation of diagnostic research, an ecological indicator may also be used to identify major ecosystem stress.

(Adapted from U.S. Environmental Protection Agency.)


bioleaching
Extraction of metals from ores or soil by biological processes, mostly by microorganisms.

biologic monitoring
Measuring hazardous substances in biologic materials (such as blood, hair, urine, or breath) to determine whether exposure has occurred. A blood test for lead is an example of biologic monitoring.

biological activity
The specific activity or capacity of a product to achieve a defined biological effect. Potency is the quantitative measure of biological activity.

biological half life
(in Toxicokinetics)
For a substance, the time required for the amount of that substance in a biological system to be reduced to one half of its value by biological processes, when the rate of the removal is approximately exponential.

biological magnification
Refers to the process whereby certain substances such as pesticides or heavy metals move up the food chain, work their way into rivers or lakes, and are eaten by aquatic organisms such as fish, which in turn are eaten by large birds, animals or humans. The substances become concentrated in tissues or internal organs as they move up the chain.

biological mass spectrometry
The field of mass spectrometry dealing with organic materials derived from biological systems. The spectrometry is different from organic mass spectrometry in that organic molecules are analyzed from the standpoint of biological function and the life sciences.

biological monitoring
continuous or repeated measurement of potentially toxic substances or their metabolites or biochemical effects in tissues, secreta, excreta, expired air or any combination of these in order to evaluate occupational or environmental exposure and health risk by comparison with appropriate reference values based on knowledge of the probable relationship between ambient exposure and resultant adverse health effects

biomagnification
The increase in concentration of an element or compound that occurs in a food chain across trophic levels

biomagnification factor, B
Ratio of concentrations of a compound at two consecutive trophic levels at steady state. It can also be
expressed in terms of a rate constant-based bioaccumulation model

B = Cn/Cn–1= αf/ke

where α is assimilation efficiency, f is feeding rate, and ke is the first-order elimination constant. B can be calculated from field data on assumed trophic relations or from laboratory feeding experiments.
See also: trophic enrichment factor.

biomarker
  1. Parameter that can be used to identify a toxic effect in an individual organism and can be used in extrapolation betweeen species;
  2. Indicator signalling an event or condition in a biological system or sample and giving a measure of exposure, effect ot susceptibility

biomass
The dry weight estimation of organisms (usually microorganisms) in a given habitat or medium.

biomethylation
methylation of a substance by enzymes in vitro and in vivo

biomolecule
A compound that occurs naturally in a biological  system. It can be a small molecule (sugar, lipid,  sterol, amino acid, nucleoside, nucleotide, peptide)  or a large molecule (protein, enzyme,  polysaccharide, DNA, RNA).

biopolymer
A polymer that occurs naturally in a biological system, including polypeptides, proteins, DNA, RNA and oligosaccharides.

bioremediation
Use of living organisms such as microbes, fungi, plants or their enzymes to clean up oil spills or remove other pollutants from soil, water, or wastewater; use of organisms such as non-harmful insects to remove agricultural pests or counteract diseases of trees, plants, and garden soil.

biosensor
A device that uses specific biochemical reactions mediated by isolated enzymes , immunosystems, tissues, organelles or whole cells to detect chemical compounds, usually by electrical, thermal or optical signals.

biosorption
term used to describe the property of biomass to retain ions, mainly of heavy metals and radionuclides. The biosorption mechanisms, which are complex and poorly understodd, depend on whether the organisms are living or dead, the type of substrate, and the elemental species.

biota
Plants and animals in an environment. Some of these plants and animals might be sources of food, clothing, or medicines for people.

Source: ATSDR  Glossary of Terms

biotransformation
Chemical conversion of a substance that is mediated by living organisms or enzyme preparations derived therefrom.

bismuth subsalicylate
A bismuth salt of salicylic acid. Little absorbed from the gastrointestinal tract, bismuth subsalicylate exerts a local effect on the gastric mucosa, coating it and protecting it from the corrosive effects of acid and pepsin. This agent also has local antimicrobial properties.

blackfoot disease
Blackfoot disease (BFD) is a severe form of peripheral vascular disease (PVD), in which the blood vessels in the lower limbs are severely damaged, resulting eventually in progressive gangrene. It has been observed in certain areas along the southwestern coast of Taiwan where the average concentration of dissolved arsenic in the wells is 671 ± 149 µg/L with an average As(III)/As(V) ratio of 2.6. The first symptons of the disease are the spottet discoloration of the skin on the feet that turns from brown to black as the disease develops until amputation of the affected extremities, the final resort to save the BFD victims, becomes necesaary.

Blackfoot disease
Blackfoot disease (BFD) is a severe form of peripheral vascular disease (PVD), in which the blood vessels in the lower limbs are severely damaged, resulting eventually in progressive gangrene. It has been observed in Taiwan.

blank solution
a solution that does not contain a detectable amount of the analyte of interest. The blank solution is typically used for calibration purposes. Depending on its purpose the following blank solutions can be defined:
  • Calibration blank (the solution used for creating the zero concentration point of the calibration graph; this solution contains only the diluent used for making the standard solution)
  • Reagent blank (a blank solution that contains the reagents used to dissolve the samples such as acids used for digestion; the reading for this solution is typically substracted from sample readings)
  • Method blank (a blank solution that has been handled similar to a sample, and to which the same reagents have been added, that had contact to the same type of vessels and that was treated by a similar procedure. This solution than is handled to monitor any type of contamination taking place with the method used.

The correct treatment of the analytical result for the blank solution does have a significant effect on the correctness of analytical results, especially for samples having analyte concentrations close to the limit of quantitation. Especially the measurement of the reagent and method blank must be well differentiated from the baseline correction.


blaze angle
a) Tilt of an echellette with respect to the plane of a diffraction grating. b) Angle of incidence and diffraction at which the efficiency of a grating is maximum i.e. where light intensity diffracted/incident intensity is maximum.

bleed
The loss of material from a column or septum caused by hightemperature operation. Bleed can result in ghost peaks and increased detector baseline offset and noise.

blinding
Clinical trial technique in which, to eliminate bias in a research study, subjects (and sometimes clinical investigators [double blind]) remain unaware of which therapeutic approach (for example, investigational product or standard treatment) is provided.

blood-brain barrier
To protect the brain from infection and from damage that could be caused by foreign chemicals, the endothelial cell linings of its capillaries are tighly packed together. Nothing but water and nutrients that are actively transported by cellular mechanisms can pass through.

blotting
Transfer of nucleic acids or proteins from an electrophoretic gel strip to a chemically reactive paper or membrane (such as nitrocellulose paper) or matrix (nylon,, for5 example) - to which they bind. Blotting is achieved through capillary diffusion (when the gel is placed between the paper or matrix and an absorptive pad) or through electrophoresis (electroblotting). Of the three types of blots, Southern hybridization (or Southern blot) transfers DNA; Northern blots transfer RNA, and Western blots transfer proteins (also called protein blots).

BMOV
Bis(maltolato)oxovanadium(IV) (BMOV) can be synthesized by simple metathesis of vanadyl sulfate trihydrate and maltol (3-hydroxy-2-methyl-4-pyrone)  (1:2). The ligand itself is commercially available and is an approved food additive in many countries,  including Canada, the United Kingdom, and the  United States. BMOV can be prepared in >90% yield  in water, has a molecular weight of 317 and is soluble  (millimolar scale) in a number of organic solvents as  well as water. These properties together  (neutral charge and aqueous solubility) contribute  to high oral bioavailability. With these considerations in mind, the pentacoordinate, oxovanadium(IV) complex was developed, specifically as a potential insulin-mimetic agent.

body burden
The total amount of a substance in the body. Some substances build up in the body because they are stored in fat or bone or because they leave the body very slowly.

bond
A mechanism through which atoms, ions, or group of atoms are held together in a molecule.

bonded phase
A bonded phase (in chromatography) is a stationary phase which is covalently bonded to the support particles or to the inside wall of the column tubing.

bottom ash
relatively coarse uncombusted or partly combusted residue of incineration that accumulates on the grate of a furnace

boxcar integration
Observation of a periodically-generated signal at a controlled time after each repetition is initiated. By averaging many repetitions at a given delay after event initiation, one obtains a more precise measurement of the behavior of the repetitive event's time course than could be obtained with a single observation.

bromate
BrO3-. An inorganic anion, bromate is tasteless and colourless, with a low volatility. As a moderately strong oxidant, bromate is reactive.
Normally, bromate is not found in nature, but it is a water disinfection byproduct. It is formed during ozonation when ozone used to disinfect drinking water reacts with (oxidises) naturally occurring bromide ions. Bromate is the main cause for concern of ozonation as water treatment method. The amount of bromate produced is influenced by the amount of (naturally occurring) bromide in the water.

bromide
Br-. An inorganic bromide anion. Also used to describe any compound (usually a bromide salt) that contains the Br- ion, such as sodium bromide (NaBr).
Inorganic bromide is widely distributed in the environment. It is commonly found in natural waters, that is, streams, lakes and reservoirs. Br- comes from wastewater discharges, agricultural run-off (mainly from soil fumigation) and run-off from roads. The bromide ion is a precursor to water disinfectant by products when ozone or possibly hypochlorite (bleach) are used as disinfectants, and therefore needs to be controlled. The bromide ion itself is sometimes used as a water disinfectant because, in water it forms hypobromous acid (HOBr) considered as a strong disinfectant.

buffer
A solution that maintains constant  pH by resisting changes in pH from dilution or addition of small amounts of  acids and bases. 

buffer capacity
A quantitative measure of the potential of a buffer solution  (defined as the number of equivalents of  strong acid or base to cause a one pH unit  change in 1 L of a buffer solution) or simply  the ability of a buffer to withstand  injections of a buffered sample solution  without changing mobile-phase pH; capacity  determined by pH, buffer pKa, and  buffer concentration.

bulk analysis
Chemical analysis of an entire sample body (rock, soil) or a sub part with little or no segregation of specific areas or components.


butylation
introduction of a butyl group into a compound

see also: alkylation











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