Rapid Thin Layer Chromatographic Method for Determining Aflatoxin Bi, Ochratoxin A, and Zearalenone in Corn

1978 ◽  
Vol 61 (3) ◽  
pp. 584-585
Author(s):  
Ivan Balzer ◽  
Čedo Bogdanić ◽  
Stjepan Pepeljnjak
Keyword(s):  
Sodium Bicarbonate ◽  
Thin Layer ◽  
Ochratoxin A ◽  
Ultraviolet Light ◽  
Aflatoxin B1 ◽  
Chromatographic Method ◽  
Limits Of Detection ◽  
Chloroform Extraction ◽  
Tlc Plates

Abstract A multimycotoxin thin layer chromatographic method is described for the analysis of corn. Aflatoxins are extracted from the samples with acetonitrile-water, and sodium bicarbonate is added to separate the acidic ochratoxin from zearalenone and aflatoxin B1. After chloroform extraction, 1/V NaOH is added to separate zearalenone and aflatoxin B1# The separated mycotoxins are spotted on TLC plates, which are then examined under ultraviolet light. The following recoveries ( % ) were obtained for corn samples: aflatoxin B1 71, ochratoxin A 87, and zearalenone 85. The limits of detection for the respective mycotoxins were 2, 40, and 200 ppb.

Screening Method for the Detection of Aflatoxins, Ochratoxin, Patulin, Sterigmatocystin, and Zearalenone in Cereals

1977 ◽  
Vol 60 (6) ◽  
pp. 1369-1371 ◽  
Author(s):  
B G Egon Josefsson ◽  
Tord E Möller
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Ochratoxin A ◽  
Screening Method ◽  
Gel Filtration ◽  
Limits Of Detection ◽  
Layer Chromatography

Abstract A screening method has been developed for the detection of aflatoxins, ochratoxin A, patulin, sterigmatocystin, and zearalenone in cereals. After extraction, the sample is cleaned up by gel filtration. The mycotoxins are separated by thin layer chromatography. The limits of detection are about 5 μg aflatoxins, 10 ochratoxin A, 50 μg patulin, 10 μg sterigmatocystin, and 35 μg zearalenone/kg.

Detection of Ochratoxin A in Barley, Using Silica Gel Minicolumns

1975 ◽  
Vol 58 (1) ◽  
pp. 156-158
Author(s):  
Benedicte Hald ◽  
Palle Krogh
Keyword(s):  
Sodium Bicarbonate ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Ochratoxin A ◽  
Silica Gel ◽  
Fluorescent Band ◽  
Contamination Levels ◽  
Simplified Procedure ◽  
Green Fluorescent ◽  
Layer Chromatography

Abstract A simplified procedure has been developed to detect ochratoxin A in cereals which can be used in the field where equipment for thin layer chromatography is not available. The procedure includes extraction of the acidified sample with chloroform, purification over sodium bicarbonate, and minicolumn chromatography. Under longwave ultraviolet light ochratoxin A appears as a blue-green fluorescent band at the lower end of the column. Contamination levels as low as 12 ppb can be detected by this method.

Rapid Thin Layer Chromatographic Method for the Detection of Histamine in Fish Products

1976 ◽  
Vol 59 (6) ◽  
pp. 1224-1225 ◽  
Author(s):  
David E Schutz ◽  
George W Chang ◽  
Leonard F Bjeldanes
Keyword(s):  
Thin Layer ◽  
Chromatographic Separation ◽  
Chromatographic Method ◽  
Ammonium Hydroxide ◽  
Fish Products ◽  
Fish Flesh ◽  
Fish Samples ◽  
Tlc Plates

Abstract A rapid, convenient thin layer chromatographic (TLC) method for detecting histamine in fish samples is described. Samples of press juice or fish flesh are applied directly to TLC plates. The plates are developed with acetone-ammonium hydroxide (95+5) and the spots are visualized with ninhydrin or Pauly’s reagent. Chromatographic separation of histamine from other fish components is readily achieved by this method.

Two-Dimensional Thin-Layer Chromatographic Method for the Analysis of Ochratoxin A in Green Coffee

2005 ◽  
Vol 68 (9) ◽  
pp. 1920-1922 ◽  
Author(s):  
MERITXELL VENTURA ◽  
IVAN ANAYA ◽  
FRANCESC BROTO-PUIG ◽  
MONTSERRAT AGUT ◽  
LLUÍS COMELLAS
Keyword(s):  
Thin Layer ◽  
Formic Acid ◽  
Ochratoxin A ◽  
Chromatographic Method ◽  
Low Cost ◽  
Chlorinated Solvents ◽  
Sodium Bicarbonate Solution ◽  
Coffee Bean ◽  
Green Coffee ◽  
Two Dimensional

A low-cost thin-layer chromatographic method has been developed for the presumptive measurement of ochratoxin A (OTA) at 5 μg/kg in green coffee beans. The analytical method consisted of extracting OTA by shaking the beans with a mixture of methanol and aqueous sodium bicarbonate solution, which was then purified by liquid-liquid partition into toluene. OTA was separated by normal-phase two-dimensional thin-layer chromatography and detected by visual estimation of fluorescence intensity under a UV lamp at 365 nm. The chromatography solvents were toluene–methanol–formic acid (8:2:0.03) for the first development and petroleum ether–ethyl acetate–formic acid (8:10:1) for the second dimension development. This method was tested with uncontaminated green coffee bean samples spiked with an OTA standard at four different concentrations (5, 10, 20, and 30 μg/kg). The method is rapid, simple, and very easy to implement in coffee-producing countries. It is highly selective and does not involve the use of chlorinated solvents in the sample extraction step. This inexpensive method has been applied to different types of green coffee samples from various countries (Zimbabwe, Brazil, India, Uganda, Colombia, and Indonesia) and different manufacturers, and no OTA below the detection limit of 5 μg/kg was detected in any samples analyzed.

Isolation and Determination of Aflatoxin B1 in Cottonseed Meals

1965 ◽  
Vol 48 (4) ◽  
pp. 815-818
Author(s):  
R H Engebrecht ◽  
J L Ayres ◽  
R O Sinnhuber
Keyword(s):  
Rainbow Trout ◽  
Thin Layer ◽  
Ultraviolet Light ◽  
Cottonseed Meal ◽  
Silicic Acid ◽  
Aflatoxin B1 ◽  
Chloroform Solution ◽  
Fluorescent Material ◽  
Acetone Extraction

Abstract A method for the isolation and determination of aflatoxins in commercial samples of cottonseed meal has been devised. Meal samples were defatted with hexane and the aflatoxins removed from the meal by acetone extraction. The pigments and residual lipids were removed from the acetone by nitration of the cold solution. The anatoxin was further isolated by evaporating the acetone and redissolving the residue in hot methanol. After cooling, the insolubles were discarded and the methanol-soluble materials taken up in chloroform. The chloroform solution was spotted on silicic acid thin layer chromatographic plates along with suitable anatoxin standards. After development with 9:1 (v/v) chloroform :acetone, the chromatographic plates were examined under ultraviolet light. Four of the eight cottonseed meals examined contained fluorescent material chromatographically similar to aflatoxin B1 in amounts varying from 19 to 186 parts per billion (ppb). The identity of the material in the 186 ppb sample was verified as aflatoxin by duckling bioassay. Trials using rainbow trout confirmed the chemical findings. These trout experiments will be described in detail in another report.

Thin Layer Chromatographic Method for Analysis and Chemical Confirmation of Sterigmatocystin in Cheese

1980 ◽  
Vol 63 (1) ◽  
pp. 110-114 ◽  
Author(s):  
Hans P Van Egmond ◽  
Walter E Paulsch ◽  
Ellen Deijll ◽  
Pieter L Schuller
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Trifluoroacetic Acid ◽  
Quantitative Method ◽  
Chromatographic Method ◽  
Aspergillus Versicolor ◽  
Spray Reagent ◽  
Tlc Plates ◽  
Layer Chromatography

Abstract A semi-quantitative method is described for the analysis of sterigmatocystin in cheese. The method is based on extraction of cheese with MeOH-4% KC1 (9+1), followed by Florisil and polyamide column cleanup and 2-dimensionaI thin layer chromatography (TLC). Visualization of sterigmatocystin on the TLC plates is enhanced by an ALCL3 spray reagent. The identity of sterigmatocystin is confirmed by a 2-dimensional TLC test based on reaction with trifluoroacetic acid (TFA) on the plate after first development. The reaction product formed is visualized by spraying with ALCL3. The method allows detection and confirmation of sterigmatocystin in cheese at concentrations as low as 5 μg/kg. The method has been applied to cheese samples ripening in warehouses and naturally molded with Aspergillus versicolor

Improved Detection of Ochratoxin A on Thin Layer Plates

1971 ◽  
Vol 54 (6) ◽  
pp. 1307-1309
Author(s):  
Hugh L Trenk ◽  
Fun Sun Chu
Keyword(s):  
Carboxylic Acid ◽  
Thin Layer ◽  
Ochratoxin A ◽  
Fluorescence Intensity ◽  
Densitometric Analysis ◽  
Hydrolysis Products ◽  
Tlc Plates ◽  
Fluorescent Spectra

Abstract The fluorescent spectra of ochratoxins A, B, and C, one of the hydrolysis products of ochratoxin A, i.e., 5-chloro-3,4-dihydro-8-hydroxy-3-methylisocoumarin-7-carboxylic acid, and their respective ammoniated derivatives have been studied. The excitation maxima of these compounds shifted to a longer wavelength after exposure to ammonia fumes, whereas the emission maxima shifted to a shorter wavelength. The fluorescence intensity of ammoniated ochratoxin A was found to be almost twice that of ochratoxin A. It is suggested that TLC plates be exposed to ammonia fumes prior to densitometric analysis to increase the sensitivity of the assay for ochratoxin A.

Mycotoxins in Animal Feedstuffs: Sensitive Thin Layer Chromatographic Detection of Aflatoxin, Ochratoxin A, Sterigmatocystin, Zearalenone, and T-2 Toxin

1979 ◽  
Vol 62 (6) ◽  
pp. 1265-1267
Author(s):  
Deryck S P Patterson ◽  
Basil A Roberts
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Ochratoxin A ◽  
Aflatoxin B1 ◽  
Detection Limits ◽  
Chromatographic Detection ◽  
Solvent Systems ◽  
Animal Feedstuffs ◽  
Layer Chromatography

Abstract Improvements have been made to a previously described multi-mycotoxin method that involved a membrane cleanup step. Using 2-dimensional thin layer chromatography and appropriate solvent systems, aflatoxin B1 can be detected in mixed feedstuffs and various ingredients at levels ranging from 0.1 to 0.3 μg/kg. Corresponding detection limits for ochratoxin A and sterigmatocystin are 5 to 20 μg/kg and for T-2 toxin and zearalenone 20 to 200 μg/kg.

Chemical Confirmatory Tests for Ochratoxin A, Citrinin, Penicillic Acid, Sterigmatocystin, and Zearalenone Performed Directly on Thin Layer Chromatographic Plates

1984 ◽  
Vol 67 (6) ◽  
pp. 1108-1110
Author(s):  
Piotr Goliński ◽  
Jadwiga Grabarkiewicz-Szczęsna
Keyword(s):  
Oxalic Acid ◽  
Acetic Anhydride ◽  
Thin Layer ◽  
Ethyl Acetate ◽  
Ochratoxin A ◽  
Penicillic Acid ◽  
Confirmatory Tests ◽  
Tlc Plates ◽  
Layer Chromatography ◽  
Fluorescent Compounds

Abstract Published tests have been improved and a new procedure is described for chemical confirmation of mycotoxins directly on thin layer plates. After extraction and preliminary cleanup chromatography with nhexane or chloroform, the mycotoxins ochratoxin A, citrinin, penicillic acid, sterigmatocystin, and zearalenone were easily separated by thin layer chromatography (TLC) using toluene-ethyl acetate-90% formic acid (6 + 3 + 1) developing solvent. In chemical confirmatory methods, the developed chromatogram was exposed to vapors of pyridine, acetic anhydride, or a mixture, or the mycotoxins were over-spotted. With this treatment, ochratoxin A, citrinin, penicillic acid, and zearalenone were converted to new fluorescent compounds, and observed under 365 nm light after re-chromatography with the same developing solvent. Sterigmatocystin was confirmed chemically using TLC plates impregnated with 0.6N H2S04 or 10% oxalic acid in methanol. The described procedures are satisfactory for confirming mycotoxins present in standards, artificially contaminated grain samples (barley, corn, oat, rye, and wheat), and extracts from both fungal cultures and naturally contaminated grain samples.

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