Confirmatory Tests for Aflatoxin B1

1964 ◽  
Vol 47 (5) ◽  
pp. 801-803 ◽  
Author(s):  
Peter John Andrellos ◽  
George R Reid
Keyword(s):  
Acetic Acid ◽  
Thin Layer ◽  
Formic Acid ◽  
Thionyl Chloride ◽  
Aflatoxin B1 ◽  
Trifluoroacetic Acid ◽  
Reaction Products ◽  
Confirmatory Tests ◽  
Aflatoxin B ◽  
Layer Chromatography

Abstract Three confirmatory tests have been devised to identify aflatoxin B±. Portions of the isolated toxin are treated with formic acid-thionyl chloride, acetic acid-thionyl chloride, and trifluoroacetic acid, respectively, and aliquots of the three fluorescent reaction products are spotted on thin-layer chromatography plates. Standards treated with each of the three reagents, plus an untreated standard, are spotted on the same plate, and after development the spots are compared under ultraviolet light.

Thin Layer Chromatographic Determination of Aflatoxin in Corn Dust

1981 ◽  
Vol 64 (5) ◽  
pp. 1060-1063 ◽  
Author(s):  
Odette L Shotwell ◽  
William R Burg ◽  
Thomas Diller
Keyword(s):  
Thin Layer ◽  
Formic Acid ◽  
Ethyl Acetate ◽  
Aflatoxin B1 ◽  
American Association ◽  
Limit Of Detection ◽  
Chromatographic Determination ◽  
Acetone Water ◽  
Layer Chromatography

Abstract Methods adopted by the AOAC and the American Association of Cereal Chemists for determining aflatoxin in corn were modified, and techniques were developed for application to samples of <1 to 10 g instead of the specified 50 g samples. Analysis included chloroform extraction of dust samples or dust collected from glass fiber filters, purification of extracts on a silica gel column of appropriate size, and measurement of aflatoxin by either 1- or 2-dimensional thin layer chromatography (TLC). The solvent for 1-dimensional TLC was chloroform-acetonewater (91 + 9 + 1). Solvents for 2-dimensional TLC were, first direction, ether-methanol-water (95 + 4 + 1, lined tank) and second direction, chloroformacetone- water (91 + 9 + 1, unlined tank), or first direction, chloroform-acetone-water (91 + 9 + 1, unlined tank) and second direction, toluene-ethyl acetate- formic acid (60 + 30 + 10, unlined tank). When samples weighed ≤0.1 g, the entire concentrated extract was applied to the TLC plate. About 0.5-1.0 ng aflatoxin B1 could be detected on the plate, making the limit of detection about 9 ng/g for 0.1 g samples.

A Convenient Thin Layer Chromatographic Cleanup Procedure for Screening Several Mycotoxins in Oils

1975 ◽  
Vol 58 (3) ◽  
pp. 620-621
Author(s):  
Susie N Hagan ◽  
William H Tietjen
Keyword(s):  
Acetic Acid ◽  
Thin Layer ◽  
Formic Acid ◽  
Soybean Oil ◽  
Ethyl Acetate ◽  
Aflatoxin B1 ◽  
Corn Oil ◽  
Second Development ◽  
Cleanup Procedure ◽  
Seed Extracts

Abstract A thin layer chromatographic cleanup development with benzene-hexane (34+1) effectively removed lipids and some contaminants from mixtures of mycotoxins in corn oil, olive oil, peanut oil, soybean oil, and seed extracts. A second development in the same direction as the first, using toluene-ethyl acetate-formic acid ( 6+3+1 ) or benzene-acetic acid (9+l), separated the mycotoxins. Satisfactory separation was achieved for commercial oils spiked with sterigmatocystin, zearalenone, ochratoxins A, B, and C, and anatoxins B1 B2, Gl and G2. This technique permits detection of 5 ppb aflatoxin B1 in corn.

Collaborative Study of a Method for the Identification of Afiatoxin B1 by Derivative Formation

1967 ◽  
Vol 50 (2) ◽  
pp. 354-360 ◽  
Author(s):  
Leonard Stoloff
Keyword(s):  
Acetic Acid ◽  
Formic Acid ◽  
Silica Gel ◽  
Thionyl Chloride ◽  
Trifluoroacetic Acid ◽  
Glacial Acetic Acid ◽  
Collaborative Study ◽  
Side Reaction ◽  
Chromatographic Behavior ◽  
Definition Of

Abstract A modification of the Andrellos procedure for identification of afiatoxin B1 was studied collaboratively in 19 laboratories. The procedure, based on the altered chromatographic behavior of the afiatoxin after reactions with trifluoroacetic acid, formic acid/thionyl chloride, and glacial acetic acid/thionyl chloride, was modified by an improved silica gel column cleanup and a clearer definition of sources of difficulty. Each collaborator examined 3 extract samples: two naturally contaminated with 5 μg afiatoxin B1/sample, and one aflatoxin-free extract to which an afiatoxin B2 artifact was added. No false identifications were made. Sixteen laboratories obtained reasonably good results with the trifluoroacetic acid and formic acid/thionyl chloride reagents. Twelve laboratories obtained reasonably good results with the acetic acid/thionyl chloride reagent but there was general difficulty with a side reaction assumed to be caused by inability to maintain anhydrous conditions. The method was recommended for adoption as official, first action.

Confirmatory Test for Aflatoxin M1 on a Thin Layer Plate

1978 ◽  
Vol 61 (4) ◽  
pp. 809-812 ◽  
Author(s):  
Hans P Van Egmond ◽  
Walter E Paulsch ◽  
Pieter L Schuller
Keyword(s):  
Acetic Acid ◽  
Thin Layer ◽  
Aflatoxin B1 ◽  
Trifluoroacetic Acid ◽  
Acid Water ◽  
Confirmatory Test ◽  
Thin Layer Plate ◽  
Aflatoxin M1 ◽  
Acetic Acid Water ◽  
Fluorescent Derivative

Abstract The identity of aflatoxin M1 can easily be confirmed directly on a thin layer plate by reacting aflatoxin M1 with trifluoroacetic acid (TFA). This confirmation reaction is carried out on the thin layer plate which has been developed in 2 dimensions and used for the quantitation of aflatoxin M1 in the sample. TFA is superimposed on the separated M1 spot. The plate is kept in the dark 3 min, heated to 75°C for 5 min, and developed with chloroformmethanol-acetic acid-water (92+8+2+0.8). The Rf value of the blue-fluorescent derivative is compared with that for the M1 standard. The method was used successfully on extracts of milk, cheese, and liver. M1 quantities on the plate as low as 0.5 ng can be confirmed by this method. The method is also suitable for simultaneous confirmation of aflatoxin B1.

scholarly journals A validated quantification of triclosan in toothpaste using high-performance thin-layer chromatography and a 48-bit fatbed scanner

2021 ◽  
Author(s):  
Barbara Anders ◽  
Sabrina Doll ◽  
Bernd Spangenberg
Keyword(s):  
Acetic Acid ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
High Performance ◽  
Detection System ◽  
Flatbed Scanner ◽  
Butyl Ether ◽  
Quantification Method ◽  
Direct Measurements ◽  
Layer Chromatography

AbstractWe present a densitometric quantification method for triclosan in toothpaste, separated by high-performance thin-layer chromatography (HPTLC) and using a 48-bit flatbed scanner as the detection system. The sample was band-wise applied to HPTLC plates (10 × 20 cm), with fluorescent dye, Merck, Germany (1.05554). The plates were developed in a vertical developing chamber with 20 min of chamber saturation over 70 mm, using n-heptane–methyl tert-butyl ether–acetic acid (92:8:0.1, V/V) as solvent. The RF value of triclosan is hRF = 22.4, and quantification is based on direct measurements using an inexpensive 48-bit flatbed scanner for color measurements (in red, green, and blue) after plate staining with 2,6-dichloroquinone-4-chloroimide (Gibbs' reagent). Evaluation of the red channel makes the measurements of triclosan very specific. For linearization, an extended Kubelka–Munk expression was used for data transformation. The range of linearity covers more than two orders of magnitude and is between 91 and 1000 ng. The separation method is inexpensive, fast and reliable.

Synthesis of L-glucurone. Conversion of D-glucose into L-glucose

1969 ◽  
Vol 47 (21) ◽  
pp. 3931-3934 ◽  
Author(s):  
Walter Sowa
Keyword(s):  
Thin Layer ◽  
Trifluoroacetic Acid ◽  
Periodic Acid ◽  
Small Scale ◽  
Borohydride Reduction ◽  
Isopropylidene Derivative ◽  
Molar Equivalent ◽  
Intermediate Oxidation ◽  
Layer Chromatography ◽  
Hydrolysis Of

L-Glucurone (2) was readily prepared on a small scale by treatment of D-glycero-D-gulo-heptono-lactone (1) with a molar equivalent of periodic acid; thin–layer chromatography was used for its isolation. On a larger scale pure crystalline L-glucurone was obtained in over 80% yield from 3,5;6,7-di-O-isopropylidene-D-glycero-D-gulo-heptonolactone (4) in two steps consisting of concomitant hydrolysis and oxidation of 4 with periodic acid followed by treatment of the intermediate oxidation product with trifluoroacetic acid. L-Glucose was prepared from L-glucurone by borohydride reduction and hydrolysis of the 1,2-O-isopropylidene derivative. Since 1 was derived from D-glucose, the result of this series of reactions was the conversion of D-glucose into its enantiomer L-glucose.

Notizen: Improved 2,4-Dinitrophenylhydrazine, Thin Layer Chromatography Methods for the Determination of Micro- and Macroamounts of Ascorbic Acid

1974 ◽  
Vol 29 (11-12) ◽  
pp. 777-780 ◽  
Author(s):  
A. Navon ◽  
H. Z. Levinson
Keyword(s):  
Acetic Acid ◽  
Vitamin C ◽  
Thin Layer ◽  
Condensation Reaction ◽  
Dehydroascorbic Acid ◽  
Previous Method ◽  
Aqueous Acetic Acid ◽  
Tlc Plates ◽  
Layer Chromatography

Microamounts of vitamin C could be readily determined in 20 μl-samples using the 2,4-dinitrophenylhydrazine method together with separation by thin layer chromato­graphy. The condensation reaction was carried out for 5 min at 100 °C on a glass fibre disc. Purification of vitamin C hydrazones was accomplished by repeated separation on TLC plates. An aqueous solution of 65% acetic acid was em­ployed to dissolve the vitamin C hydrazones, providing maxi­mal absorbance at 500 nm. The minimum amount detectable by this method is 0.4 μg of dehydroascorbic acid. The macrodetermination of vitamin C was improved by simpli­fying a previous method and employing 65% aqueous acetic acid as a solvent for the hydrazones.

Dynamics of an Ester of 2,4-D in Organs of Three Fish Species

Weed Science ◽  
1972 ◽  
Vol 20 (1) ◽  
pp. 101-105 ◽  
Author(s):  
Charles A. Rodgers ◽  
David L. Stalling
Keyword(s):  
Acetic Acid ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Fish Species ◽  
Metabolic Products ◽  
Dichlorophenoxy Acetic Acid ◽  
Layer Chromatography

The uptake of 14C-labeled butoxyethanol ester of (2,4-dichlorophenoxy)acetic acid (BEE of 2,4-D) from water by three species of fed and fasted fish was studied. Fish were exposed to either 0.3 or 1.0 mg/L of herbicide for up to 168 hr. Combined residues of the 2,4-D ester and its metabolic products were determined radiometrically in eight tissues and organs. Extracts of these organs were examined by thin layer chromatography and autoradiography. Maximum residue concentrations were observed in most organs of fed fish within 1 to 2 hr of exposure, and within 1 to 8 hr of exposure for fasted fish. After maximum residue concentrations were reached, the herbicide and/or its metabolites were eliminated rapidly.

Reaction of Aflatoxin B1 with Acetic Acid-Thionyl Chloride

1969 ◽  
Vol 52 (1) ◽  
pp. 75-76
Author(s):  
Mabry Wiley ◽  
Anthony C Waiss ◽  
Nancy Bennett
Keyword(s):  
Acetic Acid ◽  
Thionyl Chloride ◽  
Aflatoxin B1 ◽  
Confirmatory Test

Abstract The two main products of the reaction of acetic aeid-thionyl chloride with aflatoxin B1, used as a confirmatory test for aflatoxin B1, were identified as the α- and β-isomers of l-acetyl-2-hydro-6-methoxydifurocoumarone

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