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)
A statistical test of significance in which the
difference between two variances is tested. A variance is the square of
a standard deviation. The F-test is often used to compare the
imprecision of two analytical methods. The hypothesis being tested
(called a null hypothesis) is that there is no difference between the
two variances. If the calculated F-value is greater than the critical
value which is obtained from a statistics table, then the null
hypothesis is rejected. This means that a difference exists and that the
difference is statistically significant, or real. If the calculated
F-value is less than the critical value, the null hypothesis cannot be
rejected, therefore, there is no difference between the two variances
being tested, and the difference is not statistically significant.
In flame atomic absorption spectrometry,
the sample is nebulized and sucked into a burner, so that analyte
elements can be atomized in a flame of a fuel gas, such as acetylene,
and an oxidation gas, usually air. The burner is positioned in such a
way that the flame region with the maximum atom concentration is in the
ray path of the spectrometer. These atoms are able to absorb element-specific radiation. To this end,
an element-specific lamp with a hollow cathode made of the element to be
investigated is introduced into the ray path of an atomic absorption
spectrometer with the atomization device and a detector. Depending on
the concentration of the element to be determined in the sample, some of
the radiation intensity of the hollow-cathode lamp is absorbed by the
atoms formed. The detection system (often a photomultiplier or photodiode) measures the intensity of the
non-attenuated radiation and the radiation after leaving the atomization
device during the supply of a sample solution. The element
concentration in the sample can then be calculated from the difference in the
Fast atom bombardment is the formation of ions by the interaction of a
focused beam of neutral atoms with a translational energy of several keV
impinging on a sample that is typically dissolved in a solvent matrix
A mass spectrometric technique that is used for the analysis of a wide
range of biomolecules, such as glycoalkaloids, glycoproteins,
polysaccharides, and peptides. Positive and negative fast atom
bombardment spectra are recorded on a mass spectrometer fitted with an
atom gun with xenon as the customary beam. The mass spectra obtained
contain molecular weight recognition as well as sequence information.
Ferrocene is the organometallic compound with the formula Fe(C5H5)2. It is the prototypical metallocene, a type of organometallic chemical compound consisting of two cyclopentadienyl rings bound on opposite sides of a central metal atom. Such organometallic compounds are also known as sandwich compounds.
A sulfate salt of mineral iron formulated for oral administration and
used as a dietary supplement, ferrous sulfate is absorbed in the
stomach and small intestine and combines with apoferritin to form
ferritin, which is stored in the liver, spleen, red bone marrow, and
intestinal mucosa. Important in transport of oxygen by hemoglobin to
the tissues, iron is also found in myoglobin, transferrin, and
ferritin, and is a component of many enzymes such as catalase,
peroxidase, and cytochromes.
A synthetic ultrasmall superparamagnetic iron oxide composed of
dextran-coated iron oxide nanoparticles (also known as 'ultrasmall
particulate iron oxides' or USPIO). Ferumoxtran-10, which accumulates
in non-cancerous lymphatic tissue, is used as a molecular resonance
imaging (MRI) contrast agent.
A superparamagnetic iron oxide nanoparticle coated with a low molecular
weight semi-synthetic carbohydrate, polyglucose sorbitol carboxymethyl
ether, with potential anti-anemic and imaging properties. After
intravenous administration, ferumoxytol replaces iron stores with fewer
side effects compared to the use of oral iron. In addition, this agent
generates T1 relaxation, producing a magnetic field and enhancing T2
relaxation, thereby darkening contrast media-containing structures in
magnetic resonance imaging (MRI). Due to small particle size,
ferumoxytol remains in the intravasculature for a prolonged period and
so may be used as a blood pool agent.
Field flow fractionation (FFF) is a family of techniques used for the separation of nanoparticles, proteins, DNA, viruses, and other materials based on size, charge, or other physical properties. Separation takes place in a thin, open channel through which samples are transported by a laminar flow of liquid. A field, applied perpendicularly to the channel flow, partitions the various components into regions of different flow velocities.
In the flight path of an ion from the source of the mass spectrometer through the mass analyzer to the detector, the ion may pass through regions in which there is no specific magnetic or electric field. These are field-free regions, as in the portion of the ion path between the electric and magnetic analyzers in a double-focusing mass spectrometer, or between the source and the first sector of both single- and double-focusing mass spectrometers. Unimolecular ion dissociations in these regions can occur to give rise to signals in the mass spectrum recorded under normal conditions (metastable ions), or can be specifically investigated.
In FPD, the detector burns heteroatomic solutes in a hydrogen–air flame. The visible-range atomic emission spectrum is filtered through an interference filter and detected with a photomultiplier tube. Different interference filters can be selected for sulfur, tin, or phosphorus emission lines. The flame photometric detector is sensitive and selective.
Flow injection analysis involves the rapid injection of a sample into a continuously flowing unsegmented carrier stream. If necesaary for detection, one or more reagent solutions are continuously merged with the carrier prior to detection. The injected sample zone undergoes dispersion and is mixed with the carrier and reagent solutions. The resultant product is transported to the detector for measurement.
The dispersion or dilution of the sample zone can be controlled and adapted to the requirements of the analysis, by varying some operational parameters including the injected sample volume, the flow rate of carrier and reagent streams, the reaction coil length, and the inner diameter of the tubing.
Flow injection mass spectrometry is a variant of flow injection
analysis in which a plug of sample is injected into a liquid carrier
stream for on-line analysis by mass spectrometry. This term is synonymous with flow injection analysis mass spectrometry.
Sequence of organisms in an ecosystem occupying specific hierarchical levels (trophic levels) such that organisms belonging to a superior level survive by eating organisms belonging to inferior levels. The chain begins with plants and ends with the largest
carnivores. The sequence can be represented as compartments in a mathematical model or analysis.
A forward library search is the process of comparing the mass spectrum
of an unknown compound with spectra in a mass spectral library,
considering only the m/z peaks that have intensities greater than a specific threshold in the unknow.
A fragment ion is the charged product of an ion dissociation. A fragment ion may be stable itself or may dissociate further to form other charged fragment ions and neutral species of successively lower mass. Molecular ions formed in the initial ionization process dissociate to fragment ions because of the excess internal energy that remains after ionization. Note that ions dissociate rather than decompose.
When electron transitions (excitation, de-excitation) occur due to electron beams or photons in a molecular system, the time required for the transition is extremely short compared to vibration between atoms. Therefore, the distance between atoms may be considered constant. While the general rotational cycle of molecules is 10-11~ 10-12 sec and the vibrational cycle is 10-13 ~ 10-14 sec, electron tran-sitions are on the order of 10-16 sec. These electron transitions are also called perpendicular transitions.
A model meant to describe metal-organism interactions determining the uptake, nutrition and toxicity of all cationic trace metals. FIAM assumes that the free metal ion activity reflects the chemical reactivity of the metal, i.e., the extent to what the metal reacts with binding sites on the cell membrane surface, and hence its bioavailability and toxicity
Fourier transform infrared spectroscopy (FTIR) is a technique which is used to obtain an infrared spectrum of absorption, emission, photoconductivity or Raman scattering of a solid, liquid or gas. An FTIR spectrometer simultaneously collects spectral data in a wide spectral range. This confers a significant advantage over a dispersive spectrometer which measures intensity over a narrow range of wavelengths at a time. FTIR technique has made dispersive infrared spectrometers all but obsolete (except sometimes in the near infrared) and opened up new applications of infrared spectroscopy.
Fullerene also called Buckyball or C60 is one of three known pure forms of carbon (graphite and diamond being the other two) that takes a spherical shape with a hollow interior. Buckyballs, named because they resemble the geodesic domes built by architect Buckminster Fuller, were discovered in 1985 among the byproducts of laser vaporization of graphite in which the carbon atoms are arranged in sheets. Though C60, referring to the number of carbon atoms that make up one sphere, is the most common fullerene, researchers have found stable, spherical carbon structures containing 70 atoms (C70), 120 (C120), 180 (C180), and others.
Robert F. Curl Jr. and Richard E. Smalley, both of Rice University in Houston, Texas and Harold W. Kroto of the University of Sussex in England, won the 1996 Nobel Prize for Chemistry for their discovery of buckminsterfullerene, the scientific name for buckyballs.
one of two classes of natural acidic organic polymer that can be extracted from humus found in soil, sediment, or aquatic environments. Its name derives from Latin fulvus, indicating its yellow colour. This organic matter is soluble in strong acid (pH = 1) and has the average chemical formula C135H182O95N5S2.