Yessotoxin
Encyclopedia
Yessotoxins are a group of lipophilic
sulphated polyester
) compounds that are structurally related to brevetoxins and ciguatoxins. They are produced by a number of planktonic algal species particularly the dinoflagellates, Lingulodinium polyedrum
, Gonylaulax spiniferia and Protoceratium reticulatum.
When the environmental conditions encourage the growth of these algal species YTXs can accumulate in the water supply and within the edible tissues of bivalve molluscs including mussels, scallops and clams
, therefore enabling the entry of YTX into the food chain
.
species Patinopecten yessoensis
in the 1960s. Since then numerous yessotoxin analogues have been isolated from shellfish
and marine algea (including 45-Hydroxyyessotoxin and carboxyyessotoxin).
Initially, scientists wrongly classified YTXs with the other lipophilic
phycotoxins that are found in shellfish. This includes the algal toxins oxadiac acid (OA), azaspiracid (AZA) and pectenotoxins (PTX). All of these toxins cause adverse health effects when present in humans. OA causes diarretic shellfish poisoning (DSP), where symptoms of poisoning include diarrhea and tumor growth and PTX can cause liver damage. Once scientists realised that YTXs did not have the same toxicological mechanism of action as the other toxins (via the inhibition of protein phosphatise) they were given their own classification.
To date none of these studies have highlighted any toxic effects of YTXs when they are present in humans. They have however found that YTX’s have toxic effects in mice when the YTX had been administered by an intraperitoneal injection into the animal. The toxicicological effects encountered are similar to those seen for paralytic shellfish toxins and include hepatotoxicity
, cardiotoxicity
and neurotoxicity
, with a YTX level of 100 µg/Kg causing toxic effects. Limited toxic effects have been seen after oral administration of the toxin to animals. The mechanism by which YTX exert a toxic effect is unknown and is currently being studied by a number of research groups. However some recent studies suggest the mode of action may have something to do with altering calcium
homeostasis
.
Although there is no data illustrating the direct association of YTX’s and toxicity in humans, issues with regards to the potential health risks of YTXs still stand due to the significant animal toxicity observed and as like other algal toxins present within shellfish
YTK’s are not destroyed by heating or freezing. As a result, several countries including New Zealand, Japan and those in Europe regulate the levels of YTX’s in shellfish. In 2002 the European commission
placed the regulatory level of 1 µg of YTXs per g-1 or 1g/kg of shellfish
meat intended for human consumption (Directive 20012/225/EC).
The analysis of YTXs is complex due to the large number of YTX analogues that can be present in the sample. Analysis is also problematic because YTXs have similar properties to other lipophilic
toxins present in the samples therefore methods can be subject to experiencing false negative or false positive results due to sample interferences.
Several experimental techniques have been developed to detect YTX’s each offering varying levels of selectivity
and sensitivity
whilst having numerous advantages and disadvantages.
, a water sample or a grown culture medium. This can be achieved by several methods:
is normally the solvent of choice but other solvents can also be used including acetone
and chloroform
. The drawback of using the solvent extraction method is that the levels of analyte recovery can be poor therefore any results obtained from the quantification
processes may not be representative of the sample.
(SPE) is another method that can be used to isolate YTXs from the sample medium. This technique separates the components of a mixture by using their different chemical and physical properties. This method is robust and extremely useful when small sample volumes are being analysed. This method is advantageous over solvent
extraction as it concentrates (can give sample enrichment up to the power of 10) and can purify
the sample by the removal of salts and non-polar substances which can interfere with the final analysis. This technique is also beneficial because it gives good levels of YTX recovery ranging from 40–50%.
toxins including okadiac acid (OA), dinophysistoxins (DTXs), azaspiracids (AZAs) and pectenotoxins (PTXs).
The MBA involves injecting the extracted toxin
into a mouse and by monitoring the mouse survival rate, the toxicity of the sample can be subsequently deduced and the analyte concentration determined. This calculation is made on the basis that one mouse unit (MU) is the minimum quantity of toxin needed to kill a mouse in 24hours. The MU is set by regulating bodies at 0.05 MU/g of animal.
The original Yasumoto MBA is subject to interferences from paralytic shellfish toxins (PSP) and free fatty acids in solution which causes false positive results. Several modifications to the MBA can be made to allow the test to be performed without these areas for error.
The MBA however still has many drawbacks;
Advantages:-
Due to these factors the other more recently developed techniques are being preferred for analysis of YTX.
that uses polyclonal antibodies against YTX to determine its concentration in the sample. The assay is commercially available and is a rapid technique that can be used for the analysis of YTXs in shellfish
, algal cells and culture samples.
This technique has several advantages: it is very sensitive, has a limit of quantification (LOQ) of 75 µg/Kg, is relatively cheap and it is easy to carry out. The major disadvantage to this method is that it cannot differentiate between the different YTX analogues and it takes a long time to generate results.
and fluorescence
detectors. All of the chromatographic techniques require a calibration
step prior to sample analysis.
Chromatographic methods with fluorescence
detection.
Liquid chromatography with Fluorescence
detection (LC-FLD) provides a selective, relatively cheap, reproducible method for the qualitative
and quantitative
analysis of YTX for shellfish
and algae samples.
This method requires an additional sample preparation step after the analyte extraction procedure has been completed (in this case SPE is preferentially used so that common interferences can be removed from the sample). This additional step involves the derivatization
of the YTXs with a fluorescent dienophile reagent
dimethoxy-4-methyl-3-oxo-3,4-dihydroquinoxalinyl)ethyl]-1,2,4-triazoline-3,5-dione (DMEQ-TAD) which facilitates analyte detection. This additional sample preparation step can make LC-FLD analysis extremely time consuming and is a major advantage of the technique.
Chromatographic methods coupled to mass spectrometry.
This technique is extremely useful for the analysis of multiple toxins. It has numerous advantages over the other techniques used. It is a sensitive and selective analytical method making it ideal for the analysis of complex samples and those with low analyte concentrations. The method is also beneficial in that it provides important structural information on the analyte which is helpful for aiding analyte identification and when unknown analytes are present in the sample. The technique has benefits over LC-FLD as the derivatisation and purification extraction steps are not necessary. For YTX analysis limits of detection of 30 mg/g of shellfish
tissue for chromatographic methods coupled to mass spectrometry have been recorded.
The major drawback to LC-MS is that the equipment is very expensive.
CE is emerging as the preferred analytical method for YTX analysis as it has significant advantages over the other analytical techniques used including; high efficiency, it has a fast and simple separation procedure, a small sample volume required and minimal reagent is required.[12]
CE techniques that can be used for YTX analysis include: CE with ultraviolet
(UV) detection and CE coupled to mass spectrometry
(MS). CEUV is a good method for YTX analysis as it is a very selective technique that can easily differentiate between YTXs and DSP toxins. The sensitivity
of these techniques can however be poor due to the low molar absorptivity
of the analytes. The technique gives a limit of detection (LOD) of 0.3 µg/ml and a LOQ of 0.9 µg/ml. The sensitivity of conventional CEUV can be improved by using micellar electrokinetic chromatography (MEKC).
CEMS has the added advantage over CEUV of being able to give molecular weight and/or structural information about the analyte. This enables the user to carry out unequivocal confirmations of the analytes present in the sample. The LOD and the LOQ have been calculated as 0.02 µg/ml and 0.08 µg/ml respectively again meeting the European Commission
Directive.
Lipophilic
Lipophilicity, , refers to the ability of a chemical compound to dissolve in fats, oils, lipids, and non-polar solvents such as hexane or toluene. These non-polar solvents are themselves lipophilic — the axiom that like dissolves like generally holds true...
sulphated polyester
Polyester
Polyester is a category of polymers which contain the ester functional group in their main chain. Although there are many polyesters, the term "polyester" as a specific material most commonly refers to polyethylene terephthalate...
) compounds that are structurally related to brevetoxins and ciguatoxins. They are produced by a number of planktonic algal species particularly the dinoflagellates, Lingulodinium polyedrum
Lingulodinium polyedrum
Lingulodinium polyedrum is a species of dinoflagellate, described by Professor Peter Franks of Scripps Institute of Oceanography as brussel sprouts covered in wooden armor that move around a lot. The organism has two forms, the classic thecate shell, and a cyst.Synonyms*Gonyaulax...
, Gonylaulax spiniferia and Protoceratium reticulatum.
When the environmental conditions encourage the growth of these algal species YTXs can accumulate in the water supply and within the edible tissues of bivalve molluscs including mussels, scallops and clams
CLaMS
CLaMS is a modular chemistry transport model system developed at Forschungszentrum Jülich, Germany. CLaMS was first described by McKenna et al. and was expanded into three dimensions by Konopka et al....
, therefore enabling the entry of YTX into the food chain
Food chain
A food web depicts feeding connections in an ecological community. Ecologists can broadly lump all life forms into one of two categories called trophic levels: 1) the autotrophs, and 2) the heterotrophs...
.
History
The first YTX analogue discovered was yessotoxin and it was initially found in the scallopScallop
A scallop is a marine bivalve mollusk of the family Pectinidae. Scallops are a cosmopolitan family, found in all of the world's oceans. Many scallops are highly prized as a food source...
species Patinopecten yessoensis
Patinopecten yessoensis
Patinopecten yessoensis is a species of scallop. Its name Yesso/Ezo refers to its being found north of Japan...
in the 1960s. Since then numerous yessotoxin analogues have been isolated from shellfish
Shellfish
Shellfish is a culinary and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater environments, some kinds are found only in freshwater...
and marine algea (including 45-Hydroxyyessotoxin and carboxyyessotoxin).
Initially, scientists wrongly classified YTXs with the other lipophilic
Lipophilic
Lipophilicity, , refers to the ability of a chemical compound to dissolve in fats, oils, lipids, and non-polar solvents such as hexane or toluene. These non-polar solvents are themselves lipophilic — the axiom that like dissolves like generally holds true...
phycotoxins that are found in shellfish. This includes the algal toxins oxadiac acid (OA), azaspiracid (AZA) and pectenotoxins (PTX). All of these toxins cause adverse health effects when present in humans. OA causes diarretic shellfish poisoning (DSP), where symptoms of poisoning include diarrhea and tumor growth and PTX can cause liver damage. Once scientists realised that YTXs did not have the same toxicological mechanism of action as the other toxins (via the inhibition of protein phosphatise) they were given their own classification.
Toxicity
A large number of studies have been conducted to assess the potential toxicity of YTX’S.To date none of these studies have highlighted any toxic effects of YTXs when they are present in humans. They have however found that YTX’s have toxic effects in mice when the YTX had been administered by an intraperitoneal injection into the animal. The toxicicological effects encountered are similar to those seen for paralytic shellfish toxins and include hepatotoxicity
Hepatotoxicity
Hepatotoxicity implies chemical-driven liver damage.The liver plays a central role in transforming and clearing chemicals and is susceptible to the toxicity from these agents. Certain medicinal agents, when taken in overdoses and sometimes even when introduced within therapeutic ranges, may injure...
, cardiotoxicity
Cardiotoxicity
Cardiotoxicity is the occurrence of heart electrophysiology dysfunction or/and muscle damage. The heart becomes weaker and is not as efficient in pumping and therefore circulating blood...
and neurotoxicity
Neurotoxicity
Neurotoxicity occurs when the exposure to natural or artificial toxic substances, which are called neurotoxins, alters the normal activity of the nervous system in such a way as to cause damage to nervous tissue. This can eventually disrupt or even kill neurons, key cells that transmit and process...
, with a YTX level of 100 µg/Kg causing toxic effects. Limited toxic effects have been seen after oral administration of the toxin to animals. The mechanism by which YTX exert a toxic effect is unknown and is currently being studied by a number of research groups. However some recent studies suggest the mode of action may have something to do with altering calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
homeostasis
Homeostasis
Homeostasis is the property of a system that regulates its internal environment and tends to maintain a stable, constant condition of properties like temperature or pH...
.
Although there is no data illustrating the direct association of YTX’s and toxicity in humans, issues with regards to the potential health risks of YTXs still stand due to the significant animal toxicity observed and as like other algal toxins present within shellfish
Shellfish
Shellfish is a culinary and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater environments, some kinds are found only in freshwater...
YTK’s are not destroyed by heating or freezing. As a result, several countries including New Zealand, Japan and those in Europe regulate the levels of YTX’s in shellfish. In 2002 the European commission
European Commission
The European Commission is the executive body of the European Union. The body is responsible for proposing legislation, implementing decisions, upholding the Union's treaties and the general day-to-day running of the Union....
placed the regulatory level of 1 µg of YTXs per g-1 or 1g/kg of shellfish
Shellfish
Shellfish is a culinary and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater environments, some kinds are found only in freshwater...
meat intended for human consumption (Directive 20012/225/EC).
Analysis
The analysis of YTX’s is necessary because of the possible health risks and the limits put in place by the European Commission directive.The analysis of YTXs is complex due to the large number of YTX analogues that can be present in the sample. Analysis is also problematic because YTXs have similar properties to other lipophilic
Lipophilic
Lipophilicity, , refers to the ability of a chemical compound to dissolve in fats, oils, lipids, and non-polar solvents such as hexane or toluene. These non-polar solvents are themselves lipophilic — the axiom that like dissolves like generally holds true...
toxins present in the samples therefore methods can be subject to experiencing false negative or false positive results due to sample interferences.
Several experimental techniques have been developed to detect YTX’s each offering varying levels of selectivity
Functional Selectivity
Functional selectivity is the ligand-dependent selectivity for certain signal transduction pathways in one and the same receptor. This can be present when a receptor has several possible signal transduction pathways...
and sensitivity
Sensitivity and specificity
Sensitivity and specificity are statistical measures of the performance of a binary classification test, also known in statistics as classification function. Sensitivity measures the proportion of actual positives which are correctly identified as such Sensitivity and specificity are statistical...
whilst having numerous advantages and disadvantages.
Extraction methods
Prior to analysis it is necessary to isolate YTXs from the sample medium whether this is the digestive gland of a shellfishShellfish
Shellfish is a culinary and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater environments, some kinds are found only in freshwater...
, a water sample or a grown culture medium. This can be achieved by several methods:
Liquid–liquid or solvent extraction
Liquid–liquid extraction or solvent extraction can be used to isolate YTX’s from the sample medium. MethanolMethanol
Methanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol...
is normally the solvent of choice but other solvents can also be used including acetone
Acetone
Acetone is the organic compound with the formula 2CO, a colorless, mobile, flammable liquid, the simplest example of the ketones.Acetone is miscible with water and serves as an important solvent in its own right, typically as the solvent of choice for cleaning purposes in the laboratory...
and chloroform
Chloroform
Chloroform is an organic compound with formula CHCl3. It is one of the four chloromethanes. The colorless, sweet-smelling, dense liquid is a trihalomethane, and is considered somewhat hazardous...
. The drawback of using the solvent extraction method is that the levels of analyte recovery can be poor therefore any results obtained from the quantification
Quantification
Quantification has several distinct senses. In mathematics and empirical science, it is the act of counting and measuring that maps human sense observations and experiences into members of some set of numbers. Quantification in this sense is fundamental to the scientific method.In logic,...
processes may not be representative of the sample.
Solid phase extraction
Solid phase extractionSolid phase extraction
Solid-phase extraction is a separation process by which compounds that are dissolved or suspended in a liquid mixture are separated from other compounds in the mixture according to their physical and chemical properties. Analytical laboratories use solid phase extraction to concentrate and purify...
(SPE) is another method that can be used to isolate YTXs from the sample medium. This technique separates the components of a mixture by using their different chemical and physical properties. This method is robust and extremely useful when small sample volumes are being analysed. This method is advantageous over solvent
Solvent
A solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...
extraction as it concentrates (can give sample enrichment up to the power of 10) and can purify
Purify
Purify is a memory debugger program used by software developers to detect memory access errors in programs, especially those written in C or C++. It was originally written by Reed Hastings of Pure Software. Pure Software later merged with Atria Software to form Pure Atria Software, which in turn...
the sample by the removal of salts and non-polar substances which can interfere with the final analysis. This technique is also beneficial because it gives good levels of YTX recovery ranging from 40–50%.
Mouse bioassay (MBA)
The MBA was developed by Yasumoto et al. and is the official reference method used to analyse for YTX and lipophilicLipophilic
Lipophilicity, , refers to the ability of a chemical compound to dissolve in fats, oils, lipids, and non-polar solvents such as hexane or toluene. These non-polar solvents are themselves lipophilic — the axiom that like dissolves like generally holds true...
toxins including okadiac acid (OA), dinophysistoxins (DTXs), azaspiracids (AZAs) and pectenotoxins (PTXs).
The MBA involves injecting the extracted toxin
Toxin
A toxin is a poisonous substance produced within living cells or organisms; man-made substances created by artificial processes are thus excluded...
into a mouse and by monitoring the mouse survival rate, the toxicity of the sample can be subsequently deduced and the analyte concentration determined. This calculation is made on the basis that one mouse unit (MU) is the minimum quantity of toxin needed to kill a mouse in 24hours. The MU is set by regulating bodies at 0.05 MU/g of animal.
The original Yasumoto MBA is subject to interferences from paralytic shellfish toxins (PSP) and free fatty acids in solution which causes false positive results. Several modifications to the MBA can be made to allow the test to be performed without these areas for error.
The MBA however still has many drawbacks;
- The method is a non specific assayAssayAn assay is a procedure in molecular biology for testing or measuring the activity of a drug or biochemical in an organism or organic sample. A quantitative assay may also measure the amount of a substance in a sample. Bioassays and immunoassays are among the many varieties of specialized...
- it is unable to differentiate between YTX and other sample components including DSP toxins - The method has economic and social issues with regards to testing on animals
- The results produced are not very reproducible
- The method has insufficient detection capabilities
Advantages:-
- The method is quick
- The method is cheap
Due to these factors the other more recently developed techniques are being preferred for analysis of YTX.
Enzyme-linked immunosorbent assay
The enzyme-linked immunosorbent assay (ELISA) technique used for the analysis of YTXs is a recently developed method by Briggs et al. It is a competitive, indirect immunoassayImmunoassay
An immunoassay is a biochemical test that measures the presence or concentration of a substance in solutions that frequently contain a complex mixture of substances. Analytes in biological liquids such as serum or urine are frequently assayed using immunoassay methods...
that uses polyclonal antibodies against YTX to determine its concentration in the sample. The assay is commercially available and is a rapid technique that can be used for the analysis of YTXs in shellfish
Shellfish
Shellfish is a culinary and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater environments, some kinds are found only in freshwater...
, algal cells and culture samples.
This technique has several advantages: it is very sensitive, has a limit of quantification (LOQ) of 75 µg/Kg, is relatively cheap and it is easy to carry out. The major disadvantage to this method is that it cannot differentiate between the different YTX analogues and it takes a long time to generate results.
Chromatographic methods
A variety of chromatographic methods can be used to analyse YTX’s. This includes chromatographic techniques coupled to mass spectrometryMass spectrometry
Mass spectrometry is an analytical technique that measures the mass-to-charge ratio of charged particles.It is used for determining masses of particles, for determining the elemental composition of a sample or molecule, and for elucidating the chemical structures of molecules, such as peptides and...
and fluorescence
Fluorescence
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation of a different wavelength. It is a form of luminescence. In most cases, emitted light has a longer wavelength, and therefore lower energy, than the absorbed radiation...
detectors. All of the chromatographic techniques require a calibration
Calibration
Calibration is a comparison between measurements – one of known magnitude or correctness made or set with one device and another measurement made in as similar a way as possible with a second device....
step prior to sample analysis.
Chromatographic methods with fluorescence
Fluorescence
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation of a different wavelength. It is a form of luminescence. In most cases, emitted light has a longer wavelength, and therefore lower energy, than the absorbed radiation...
detection.
Liquid chromatography with Fluorescence
Fluorescence
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation of a different wavelength. It is a form of luminescence. In most cases, emitted light has a longer wavelength, and therefore lower energy, than the absorbed radiation...
detection (LC-FLD) provides a selective, relatively cheap, reproducible method for the qualitative
Qualitative research
Qualitative research is a method of inquiry employed in many different academic disciplines, traditionally in the social sciences, but also in market research and further contexts. Qualitative researchers aim to gather an in-depth understanding of human behavior and the reasons that govern such...
and quantitative
Quantitative
A quantitative property is one that exists in a range of magnitudes, and can therefore be measured with a number. Measurements of any particular quantitative property are expressed as a specific quantity, referred to as a unit, multiplied by a number. Examples of physical quantities are distance,...
analysis of YTX for shellfish
Shellfish
Shellfish is a culinary and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater environments, some kinds are found only in freshwater...
and algae samples.
This method requires an additional sample preparation step after the analyte extraction procedure has been completed (in this case SPE is preferentially used so that common interferences can be removed from the sample). This additional step involves the derivatization
Derivatization
Derivatization is a technique used in chemistry which transforms a chemical compound into a product of similar chemical structure, called a derivative....
of the YTXs with a fluorescent dienophile reagent
Reagent
A reagent is a "substance or compound that is added to a system in order to bring about a chemical reaction, or added to see if a reaction occurs." Although the terms reactant and reagent are often used interchangeably, a reactant is less specifically a "substance that is consumed in the course of...
dimethoxy-4-methyl-3-oxo-3,4-dihydroquinoxalinyl)ethyl]-1,2,4-triazoline-3,5-dione (DMEQ-TAD) which facilitates analyte detection. This additional sample preparation step can make LC-FLD analysis extremely time consuming and is a major advantage of the technique.
Chromatographic methods coupled to mass spectrometry.
This technique is extremely useful for the analysis of multiple toxins. It has numerous advantages over the other techniques used. It is a sensitive and selective analytical method making it ideal for the analysis of complex samples and those with low analyte concentrations. The method is also beneficial in that it provides important structural information on the analyte which is helpful for aiding analyte identification and when unknown analytes are present in the sample. The technique has benefits over LC-FLD as the derivatisation and purification extraction steps are not necessary. For YTX analysis limits of detection of 30 mg/g of shellfish
Shellfish
Shellfish is a culinary and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater environments, some kinds are found only in freshwater...
tissue for chromatographic methods coupled to mass spectrometry have been recorded.
The major drawback to LC-MS is that the equipment is very expensive.
Capillary electrophoresis
Capillary electrophoresisCapillary electrophoresis
Capillary electrophoresis , also known as capillary zone electrophoresis , can be used to separate ionic species by their charge and frictional forces and hydrodynamic radius. In traditional electrophoresis, electrically charged analytes move in a conductive liquid medium under the influence of an...
CE is emerging as the preferred analytical method for YTX analysis as it has significant advantages over the other analytical techniques used including; high efficiency, it has a fast and simple separation procedure, a small sample volume required and minimal reagent is required.[12]
CE techniques that can be used for YTX analysis include: CE with ultraviolet
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
(UV) detection and CE coupled to mass spectrometry
Mass spectrometry
Mass spectrometry is an analytical technique that measures the mass-to-charge ratio of charged particles.It is used for determining masses of particles, for determining the elemental composition of a sample or molecule, and for elucidating the chemical structures of molecules, such as peptides and...
(MS). CEUV is a good method for YTX analysis as it is a very selective technique that can easily differentiate between YTXs and DSP toxins. The sensitivity
Sensitivity and specificity
Sensitivity and specificity are statistical measures of the performance of a binary classification test, also known in statistics as classification function. Sensitivity measures the proportion of actual positives which are correctly identified as such Sensitivity and specificity are statistical...
of these techniques can however be poor due to the low molar absorptivity
Molar absorptivity
The molar absorption coefficient, molar extinction coefficient, or molar absorptivity, is a measurement of how strongly a chemical species absorbs light at a given wavelength...
of the analytes. The technique gives a limit of detection (LOD) of 0.3 µg/ml and a LOQ of 0.9 µg/ml. The sensitivity of conventional CEUV can be improved by using micellar electrokinetic chromatography (MEKC).
CEMS has the added advantage over CEUV of being able to give molecular weight and/or structural information about the analyte. This enables the user to carry out unequivocal confirmations of the analytes present in the sample. The LOD and the LOQ have been calculated as 0.02 µg/ml and 0.08 µg/ml respectively again meeting the European Commission
European Commission
The European Commission is the executive body of the European Union. The body is responsible for proposing legislation, implementing decisions, upholding the Union's treaties and the general day-to-day running of the Union....
Directive.