Performance of the Visual, Minicolumn and TLC Methods in Detecting Aflatoxin in 20 Contaminated Lots of Farmers Stock Peanuts

1984 ◽  
Vol 11 (2) ◽  
pp. 77-83 ◽  
Author(s):  
J. I. Davidson ◽  
J. W. Dickens ◽  
V. Chew ◽  
T. H. Sanders ◽  
C. E. Holaday ◽  
...  
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Coefficient Of Variation ◽  
Visual Methods ◽  
Acceptance Level ◽  
Mean Values ◽  
Analytical Results ◽  
Aflatoxin Concentration ◽  
Layer Chromatography ◽  
Standard Grade

Abstract Standard grade samples (16) from each of 20 selected minilots were used to evaluate three methods for detecting minilots of farmers stock peanuts with unacceptable concentrations of aflatoxin. A visual, a minicolumn and a modified thin layer chromatography (TLC) method were used to compare analytical results, variation, and probability of acceptance for minilots having mean aflatoxin concentrations ranging from 8–255 ppb. Mean values obtained by each of the three methods increased linearly with mean aflatoxin concentrations of the minilots and variation for each method as determined by the variance and coefficient of variation (CV) was very large. The CV for all three methods decreased as aflatoxin concentration increased. Overall performances of the three methods were similar in accepting and rejecting these minilots on the basis of the 1.8 kg grade samples. The greatest difference in the three methods occurred at the zero acceptance level where the modified TLC, minicolumn and visual methods rejected 97, 98 and 88%, respectively, of the minilots with more than 60 ppb aflatoxin. At this acceptance level the TLC, minicolumn and visual methods also rejected 55, 50 and 30%, respectively, of the minilots with less than 30 ppb aflatoxin.

Rapid Screening of Pharmaceuticals by Thin-Layer Chromatography: Analysis of Essential Drugs by Visual Methods

1995 ◽  
Vol 78 (1) ◽  
pp. 41-49 ◽  
Author(s):  
Allen S Kenyon ◽  
Paul E Flinn ◽  
Thomas P Layloff
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
The United States ◽  
World Health ◽  
Rapid Screening ◽  
Visual Methods ◽  
Screening Process ◽  
Standard Dosage ◽  
Essential Drugs ◽  
Layer Chromatography

Abstract A method for rapidly screening pharmaceuticals by thin-layer chromatography has been designed for use in areas with limited resources and by operators with limited training. An apparatus for performing the analysis in a plastic bag under equilibrium conditions was designed. Results can be reproduced by different operators and in different locations. The analysis can be performed without electricity or in a remote area, away from a laboratory. It is especially suited for field use in developing countries. The method is low cost, maintenance-free, fast, and reliable; it also uses limited volumes of solvents. The analyses can be performed without weighing if reference materials can be supplied in tablet form, provided the drug content is listed and only one unit is required for each analysis. All procedures were developed for the analysis of drugs from a partial list of essential drugs established by the World Health Organization. Three drugs were selected and prepared in the form of reference tablets. Comparisons with the analyses of the drugs in standard dosage forms were made by using reference tablets and primary USP standards. Comparable results were obtained, proving that the screening process can be conducted by using reference tablets and without weighing either the sample or the reference. The method has been successfully demonstrated and used in Swaziland, by high school teachers in the United States, and by personnel from the Ministry of Health in Saudi Arabia. Personnel can be trained in a short time to perform screening analysis of drugs.

scholarly journals Efficacy of the Visual, Minicolumn, and Thin Layer Chromatography Methods to Test Farmers Stock Peanuts for Aflatoxin1

1986 ◽  
Vol 13 (2) ◽  
pp. 74-77 ◽  
Author(s):  
T. B. Whitaker ◽  
J. W. Dickens
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Computer Models ◽  
Visual Method ◽  
Aflatoxin Concentration ◽  
Layer Chromatography

Abstract This study estimated the efficacy of the visual A. flavus (VAF), minicolumn (MCL), and thin layer chromatography (TLC) methods to detect farmers stock peanuts which contain aflatoxin. Aflatoxin tests on grade samples from each of 2300 lots of farmers stock peanuts was used to estimate the distribution of farmers stock lots according to their aflatoxin concentration (lot distribution). This lot distribution (with an average aflatoxin concentration of 59.5 parts per billion) was incorporated into each of the 3 computer models that simulate the testing of farmers stock peanuts for aflatoxin when the VAF, MCL, and TLC methods are used. The number of lots accepted and the average aflatoxin concentration (AA) in the accepted lots was predicted. Results indicate that when a given percentage of the lots are accepted, lots accepted by the VAF method have less aflatoxin than those lots accepted by either the MCL or TLC methods. When the present visual method was used to test the above lot distribution, 75.8% of the lots tested were accepted and the AA in the accepted and rejected lots were 4.1 and 232.8 parts per billion, respectively.

PRODUCTION OF AFLATOXIN IN PRE-PACKAGED LUNCHEON MEAT AND CHEESE AT REFRIGERATOR TEMPERATURES1

1971 ◽  
Vol 34 (7) ◽  
pp. 349-351 ◽  
Author(s):  
L. S. Oldham ◽  
F. W. Oehme ◽  
D. C. Kelley
Keyword(s):  
Public Health ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Aspergillus Flavus ◽  
Aflatoxin Production ◽  
Aflatoxin Concentration ◽  
Luncheon Meat ◽  
The Common ◽  
Meat Samples ◽  
Layer Chromatography

Information is lacking on the ability of the common mold contaminant, Aspergillus flavus, to grow and produce aflatoxin in perishable foods at normal refrigerator temperatures. Because of public health interests we investigated the possibility of certain perishable foods contaminated with the mold developing an aflatoxin concentration under conditions of refrigeration. Cheddar cheese and luncheon-meat samples were inoculated with A. flavus ATCC 15517 and were refrigerated for 12 days at 4.4 or 7.2 C or incubated at 25 C for 12 days, Uninoculated cheese and meat samples were handled in the same manner. All samples were quantitatively analyzed by thin-layer chromatography for presence of aflatoxin. All samples; except those inoculated and incubated at 25 C, were negative for aflatoxin production. This indicated the mold would, not produce detectable aflatoxin in the tested foods when kept at normal refrigeration temperatures for 12 days.

scholarly journals Characteristics of Visual, Minicolumn and TLC Methods in Detecting Aflatoxin Contaminated Loads of Farmers Stock Peanuts

1989 ◽  
Vol 16 (1) ◽  
pp. 1-5
Author(s):  
Y. J. Tsai ◽  
J. I. Davidson ◽  
V. Chew ◽  
R. J. Cole ◽  
T. H. Sanders
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Empirical Models ◽  
Distribution Functions ◽  
Statistical Distribution ◽  
Visual Methods ◽  
Low Level ◽  
Operation Characteristic ◽  
Layer Chromatography ◽  
Higher Sensitivity

Abstract Results from two 1980 experiments were used to compare the performance of the visual, minicolumn and thin-layer chromatography (TLC) methods in detecting loads of farmers stock peanuts with aflatoxin. The first experiment was conducted to establish variability of the methods under ideal conditions. The second experiment was conducted to evaluate the performance of the three methods under commercial conditions. In this paper, data and empirical models were used to explore potential improvements in detecting low-level contaminated lots. The minicolumn and TLC methods were very sensitive and provided consistent measurements. Operation characteristic (OC) curves developed by using empirical models (Logistic and Gompertz) were compared to statistical distribution functions used by Whitaker and coworkers. Assuming a desired probability of acceptance of 15%, both the minicolumn and TLC methods would accept lots with 60 ppb aflatoxin, while the visual methods would accept lots with 150 ppb aflatoxin. In crop years similar to 1980, the currently used method would not segregate peanuts to meet the 1–5 ppb (total) tolerance levels and would provide excessive sheller risk. Because of their objectivity, precision and higher sensitivity, the minicolumn and TLC have potential for improving the detection of contaminated loads of farmers stock peanuts.

Thin-Layer Chromatography

1965 ◽  
Author(s):  
H. R. Bolliger ◽  
M. Brenner ◽  
H. Gänshirt ◽  
Helmut K. Mangold ◽  
H. Seiler ◽  
...  
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Layer Chromatography

THE LESS-POLAR METABOLITES PRODUCED BY INCUBATION OF TESTOSTERONE-4-14C WITH RAT AND BOVINE BRAIN

1969 ◽  
Vol 61 (4) ◽  
pp. 641-648 ◽  
Author(s):  
Leon J. Sholiton ◽  
Emile E. Werk
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Paper Chromatography ◽  
Specific Activity ◽  
Bovine Brain ◽  
Polar Fraction ◽  
End Products ◽  
Polar Metabolites ◽  
Layer Chromatography ◽  
Constant Specific Activity

ABSTRACT Rat and bovine brain have been incubated with testosterone-4-14C under standard conditions. With use of paper chromatography, the extracted metabolites were noted to fall into less-polar, iso-polar, and more polar fractions. The components of the less-polar fraction were separated by acetylation and thin-layer chromatography and the major end-products identified by recrystallization to constant specific activity or constant 3H/14C ratios. Androst-4-enedione and 5α-dihydrotestosterone were formed consistently under the conditions utilized. Trace amounts of other less-polar metabolites were noted occasionally.

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