For mycotoxin analysis

The reliability of measurements plays a pivotal role in food and agricultural areas, particularly in the case of undesirable toxic compounds such as mycotoxins. Quality-control principles for mycotoxin analysis are common to other trace analyses, so good laboratory practices, such as EN 4500, represent the heart of quality assurance requirements. Harmonized Guidelines for Internal Quality Control in Analytical Chemistry Laboratories, published by IUPAC (23), also presents valuable guidelines for the determination of mycotoxins. 

Chu, F. S. 1991. Immunoassays for trace chemical analysis Monitoring toxic chemicals in humans, food, and the environment. In "Current Immunochemical Methods for Mycotoxin Analysis" (M. Vanderlaan, L. H. Stanker, B. E. Watkins, and D. W. Roberts, eds.), pp. 140-157. American Chemical Society, Washington, DC. 

The fluorometric assay is an efficient quantitative method for mycotoxin analysis. To obtain accurate results it is very important to remove interferences before the... 

Spanjer, M.C., Scholten, J.M., Kastrup, S., Jorissen, U., Schatzki, T.F. Toyofuku, N. (2006) Sample comminution for mycotoxin analysis dry milling or slurry mixing Food Addit. 

Mycotoxins, toxic metaboUtes of some fungi, can be assayed by immunochemical techniques to determine concentration in animal feed and foodstuffs. Some of the analytes assayed in kits and the detection limits are Hsted in Table 4 (45). These assays are especially advantageous for routine analysis of large samples of foodstuffs (45,46). 

Scott PM (1993) Recent developments in methods of analysis for mycotoxins in foodstuffs. Trac-Trends Anal Chem 12 373... 

With the currently available systems for PCR-based detection and identification, however, qualitative information about the presence or absence of a certain fimgus can be obtained and this should be used to advantage in food and feed quality control because the technology has the power to provide insights into the mycotoxigenic potential of analyzed samples. This information can then be used in order to decide whether samples should proceed down the process of production or should be retained for further analysis of mycotoxins. PCR-based multiplex systems... 

The experimental data presented show that sNPS can be used as transducers, which are stable for a long time after the construction of an immune biosensor. The specific immune complex formed on the sNPS surface may be registered by measuring its photoluminescence or photoconductivity. Such immune biosensors can be applied for control of T2 mycotoxin. The biosensors developed are sensitive and simple and allows for rapid analysis and analysis in field conditions. This approach may be applied for detection of any biochemical substances which can form an immune complex. Further investigations should be directed towards studying the mechanism of the biochemical signal detection by the sNPS and characterization of all the steps of analysis. 

The working group CEN TC 275/WG 5 searched for performance criteria to be used in mycotoxin analysis and came up with a document reporting the criteria for the selection of methods (26). The criteria deal with limits of detection, minimum performance characteristics, extraction solvents, and applicability. Criteria for analytical methods in mycotoxin analysis are also included in Directive 98/53/EC (18). 

Although MIPs can overcome these problems, no appropriate MIPs had been developed before, due to the high cost and the toxicity of these mycotoxins. The authors succeeded in synthesizing a good ZON mimicking template and made with it an MIP of suitable binding characteristics. This MIP has been applied for the analysis of cereal and swine feed samples. 

While HPLC does not always produce superior results to those with TLC it allows greater versatility and is more suitable for the analysis of complex organic matrices such as cereals. HPLC coupled to sensitive detection and sophisticated data retrieval has improved the identification of selected mycotoxins at levels much less than achieved by TLC. Additional chromatographic modes such as normal-phase, reverse phase and ion-exchange chromatography have been employed. There are no truly universal detectors available for HPLC. Detectors presently in use include Fourier transform infrared detections (FT-IRD), diode array ultraviolet detection (DAD) and mass selection detectors (MSD) (Coker, 1997). 

In many instances of mycotoxin analysis there is a great need for screening methods that can analyse large volumes of food and feed samples, most of which will be mycotoxin-free. It would also be extremely helpful if such methods could be used by relatively inexperienced operators and in situations where good laboratory facilities are not available (Table 11.5). 

Immunoassay methodologies are now a major method for rapid analysis of many mycotoxins, especially aflatoxins. These immunochemical techniques are based upon quite different principles to chromatographic procedures. In essence, immunochemical procedures involve reversible binding between antigens (the... 

For mycotoxin analyses radioimmunoassay (RIA), enzyme-linked immunosorbent assay (ELISAs) and affinity chromatography are the principal immunochemical methods in commercial application. Immunoaffinity columns or cartridges for specific mycotoxins are now being increasingly used in preliminary clean-up of extracts prior to final analysis by HPLC or GLC methods. 

With at least two different SRM-transitions available for the analysis of a compound, one transition can be used for quantification ( quantifier ) and the other one for result confirmation ( qualifier ). If the branching ratio of quantifier to qualifier is found outside pre-defined ranges of acceptance, it is typically tried to apply a reanalysis with a more extensive chromatographic separation in order to overcome co-elution of interfering compound and analyte. This quantifier-qualifier-principle is used extensively in GC-MS and is now often applied for quantitative LC-MS/MS application too—especially in legally strictly regulated environments as forensic toxicology or pesticide and mycotoxin analysis in feed and foodstuff [55], In contrast,... 

Chu FS Mycotoxin analysis in Jeon IJ, Ikins WG (eds) Analyzing Food for Nutrition Labeling and Hazardous Contaminants. New York, Dekker, 1995, pp 283-332. 

Chu FS Recent studies on immunoassays for mycotoxins in Beier RC, Stanker LH (eds) Immunoassays for Residue Analysis. Food Safety ACS Symposium Series Book, Washington, American Chemical Society, 1996, No 621, pp 294—313. 

Van Egmond HP Current situation on regulations for mycotoxins Overview of tolerances and status of standard methods of sampling and analysis. Food Addit Contam 1989 6 134-188. 

Analysis of Plants and Plant-Derived Products for Mycotoxins... 

Older methods were usually based on the visual determination of dark spots on a bright fluorescent plate under UV light. Another use of TLC in the determination of mycotoxin residues is as preparative TLC, in which specific spots are visualized, scraped, and resol-ubiUzed for further analysis (Association of Official Analytical Chemistry). 

European Committee for Standardisation, CEN (1999) Food analysis— biotoxins—criteria of analytical methods for mycotoxins, Report Reference no. CR 13505 1999E... 

The criteria for the choice of the CRM are not different from the criteria to select the material for the preparation of a laboratory reference material for method development, statistical control charts etc. The difference lies in the availability of adequate CRMs from reliable suppliers and the level of compromise which the analyst must make between an ideal situation and the reality of what is on offer. Massart and co-workers have proposed a principle component analysis to help select the best adapted CRMs available on the market to verify AAS analysis of foodstuffs [10], Their approach took into account the analytes as well as the matrix composition. Besides the fact that they highlighted a lack of sorts of CRM, in particular those having a fatty matrix, they demonstrated that such a statistical approach can help in the most appropriate selection of materials. Boenke also proposed a systematic approach for the choice of materials to be certified for mycotoxins [11] and which could be followed by potential users. The selection of the CRM by the analyst should include a certain number of parameters this can cover the following properties to fulfil the intended purpose level of concentration of the analytes ... 

Zheng MZ, Richard JL (2006) A review of rapid methods for the analysis of mycotoxins. My copathologia 161 261-273... 

Trichothecences are a class of structurally similar mycotoxins produced principally by Fusarium molds. These cyclic compounds are of interest to feed manufacturers because they can cause feed refusal or reduced feed efficiencies in some animal species (1,2,3). Several approaches have been reported for the analysis of trichothecenes in feeds and feed ingredients. Trimethylsilyl derivatives of the trichothecenes have been formed and the derivatives measured by gas chromatography using a flame ionization detector (4,3,6,7). Other workers obtained improved... 

Detection limits vary depending on the application. Assays for the detection of mycotoxins are designed to detect low parts per billion (ppb). The analysis of food allergens takes place in the lower parts per million (ppm). However, such low levels of sensitivity are not required for the analysis of other targets, such as those used in the analysis of bioengineered products and speciation. 

Chu FS. Immunoassays for mycotoxins. In Cole RJ, ed. Modern Methods in the Analysis and Structural Elucidation of Mycotoxins. New York, NY Academic Press 1986 207-237. 

Trichothecene mycotoxins are secondary metabolites of various fungal species. Structures of some trichothecene mycotoxins of interest to the US ARMY are given in Figure 1. Several methods have been reported for the analysis of these toxins (1-11, 15). Of these, mass spectrometry techniques are both sensitive and definitive when applied to toxicologic and environmental samples. With current technology, the most sensitive and qualitatively definitive analytical technique for the determination of these toxins is derivatization with an electron deficient moiety followed by analysis with negative ion chemical ionization gas chromatography-mass spectrometry (NICI-GC/HS). 

The analytical procedure that is used by this laboratory for the analysis of simple Fusarium mycotoxins will be reported separately. However, the analytical scheme is outlined in Figure 2. The method is very arduous due to several sample clean-up steps which necessitates transfer of the sample between containers. The trichothecenes and their derivatives have a tendency to adhere to glass and can be quantitatively transferred only with numerous methanol washes. While the analytical method is both sufficiently sensitive and definitive for the program requirements, the sheer amount of human manipulation required for the completion of this analysis makes it somewhat unreliable if implemented without a responsible quality assurance and quality control program. 

Immunoassays offer a sensitive, specific, cost-effective means of screening many samples for trace residues of toxic chemicals, their metabolites, and adducts. Antibodies can be used both as detectors to quantify the amount of a chemical present and in immunoaffmity chromatography to purify and concentrate material for subsequent analysis. Applications of these assays include detection of pesticide residues, mycotoxins, biomarkers of toxicity, and industrial chemicals. 

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