Collaborative Study of AOAC Methods I and III for the Determination of Aflatoxins in Peanut Butter

1974 ◽  
Vol 57 (4) ◽  
pp. 871-874
Author(s):  
Michael E Stack
Keyword(s):  
Aflatoxin B1 ◽  
Peanut Butter ◽  
Collaborative Study ◽  
Low Level ◽  
Aflatoxin Content ◽  
Accuracy And Precision ◽  
Low Levels

Abstract A collaborative study was designed and carried out to test the accuracy and precision, at low levels of contamination, of AOAC methods I, 26.015-26.020, and III, 26.026-26.030, for the determination of anatoxins in peanut butter. Ten test samples and 1 practice sample of each peanut butter were analyzed by each method. Two test samples were naturally contaminated with about 2 μg aflatoxin B1/kg. The 8 spiked samples (duplicate samples for each level) had 0, 2, 4, and 8 μg B1 added/kg and B2 was added at one-fourth the B1 level. The 7 collaborators were instructed to analyze the samples according to methods I and III except for minor modifications necessary to handle the low level of aflatoxins in the sample extracts and to quantitate the aflatoxin content both visually and densitometrically. The results of this study indicate that the analysts were able to determine the aflatoxins in the 2–10 μg/kg range with either method although method I gave better accuracy and precision and had less interferences than method III.

Determination of Total Aflatoxin Levels in Peanut Butter by Enzyme-Linked Immunosorbent Assay: Collaborative Study

1992 ◽  
Vol 75 (4) ◽  
pp. 693-697 ◽  
Author(s):  
Alan L Patey ◽  
Matthew Sharman ◽  
John Gilbert
Keyword(s):  
Immunosorbent Assay ◽  
Aflatoxin B1 ◽  
Peanut Butter ◽  
Collaborative Study ◽  
The United States ◽  
Enzyme Linked Immunosorbent Assay ◽  
Total Aflatoxin ◽  
Aflatoxin Level ◽  
Relative Standard

Abstract Laboratories in Australia, Japan, Spain, the United Kingdom, and the United States participated in a collaborative study to evaluate a commercial enzyme- linked immunosorbent assay for the determination of total aflatoxin. Collaborators were sent 10 randomly numbered samples (5 blind duplicates) of roasted peanut butter. Two pairs were "blank" peanut butters to which aflatoxin B1, B2, G1, and G2 standards had been added. The other 3 pairs of peanut butters were 1 low aflatoxin level sample and 2 naturally contaminated samples. The assay is based on indirect competition. Test samples containing (free) aflatoxin, added to aflatoxin-coated microwells, compete for specific monoclonal rat anti-aflatoxin. As the concentration of aflatoxin in the test samples increases, the amount of rat antiaflatoxin binding to the aflatoxin attached to the well decreases. After a wash step to remove unbound material, the amount of rat anti-aflatoxin bound to the well is determined by its reaction with peroxidase conjugated rabbit anti-rat globulin. Bound peroxidase activity is then determined by the addition of a substrate, whose color development is inversely proportional to the aflatoxin concentration and is measured by absorbance. Coefficients of variation (CV) for total aflatoxin concentrations, for mean levels of 9,30, and 89µg/kg, were between 28 and 37% for the low level and 2 naturally contaminated samples, which contained mainly aflatoxin B1. CVs for the spiked samples were lower (24-25%) for mean levels of 11 and 20 µg/kg; recoveries were 84 and 89%, respectively. Ranges for relative standard deviations for repeatabilty and reproducibility were 9-30% and 25-37%, respectively. The method has been adopted first action by AOAC International.

Collaborative Study on the Analysis of Aflatoxins in Peanut Butter

1966 ◽  
Vol 49 (4) ◽  
pp. 730-739
Author(s):  
A D Campbell ◽  
J T Funkhouser
Keyword(s):  
Working Group ◽  
Peanut Butter ◽  
Collaborative Study ◽  
International Study ◽  
Accuracy And Precision ◽  
Two Samples ◽  
Government Laboratories

Abstract A second collaborative study has been carried out on the determination of aflatoxin in peanut butter under the sponsorship of the Aflatoxin Methodology Working Group. Thirteen collaborators, representing industrial, independent, and government laboratories, analyzed twelve peanut butter samples containing known amounts of aflatoxin at levels of 10 and 110 μg/kg of peanut butter. Two samples of naturally contaminated peanut butter containing aflatoxins B1 and B2 were also analyzed. The study was designed to estimate the accuracy and precision of the method, both within laboratories and between laboratories. Some samples and collaborators were common to both this study and an international study sponsored by the IUPAC Results of the two studies have been compared. The method was recommended for adoption as official, first action.

Collaborative Study of Two-Dimensional Thin Layer Chromatographic Analysis of Aflatoxin B1 in Peanut Butter Extracts, Using the Antidiagonal Spot Application Technique

1973 ◽  
Vol 56 (6) ◽  
pp. 1444-1451 ◽  
Author(s):  
Paul R Beljaars ◽  
Cornelius A H Verhülsdonk ◽  
Walter E Paulsch ◽  
DHIAM H LIEM
Keyword(s):  
Aflatoxin B1 ◽  
Peanut Butter ◽  
Collaborative Study ◽  
Contamination Level ◽  
Application Technique ◽  
Tlc Plates ◽  
Contamination Levels ◽  
The One ◽  
Thin Layer Chromatographic Analysis

Abstract A collaborative study has been carried out among 20 laboratories in The Netherlands, representing governmental and industrial institutes, on the determination of aflatoxin B1 in peanut butter extracts. Blank peanut butter extracts prepared according to the proposed official Dutch method were spiked with aflatoxin B1, representing contamination levels of 0, 3, 6, and 12 μg B1/kg. Samples and standards were spotted on silica gel G TLC plates by the antidiagonal spot application technique described herein. Spotted plates were developed by 2-dimensional TLC with diethyl ether-methanol-water (94+4.5+1.5; lined tank) in the first direction and chloroform-acetone (90+10; unlined tank) in the second direction. Separated B1 spots from sample and standards developed in both directions were free from background interference. The quantity of aflatoxin B1 present in the sample was established by visual comparison of the fluorescent intensities of sample and standard B1 spots. For this procedure the variability of measurements within and between laboratories was statistically investigated: 80–90% of the complete results given by the participants were correct for the hlank and spiked extracts (contamination level of 12 μg B1/kg). For contamination levels of 3 and 6 μg B1/kg an approximate coefficient of variation of 35% was calculated for within- and between-laboratory results. Results obtained in this investigation were compared with those found by previous investigators who used the one-dimensional TLC technique. It is concluded that, with the antidiagonal procedure, small amounts of aflatoxin B1 (lowest level tested, 3 ppb) may be detected.

scholarly journals Immunoaffinity Column Cleanup with Liquid Chromatography Using Post-Column Bromination for Determination of Aflatoxins in Peanut Butter, Pistachio Paste, Fig Paste, and Paprika Powder: Collaborative Study

2000 ◽  
Vol 83 (2) ◽  
pp. 320-340 ◽  
Author(s):  
Joerg Stroka ◽  
Elke Anklam ◽  
Urban Jörissen ◽  
John Gilbert ◽  
Anna Barmark ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Aflatoxin B1 ◽  
Peanut Butter ◽  
Collaborative Study ◽  
Immunoaffinity Column ◽  
Sample Extract ◽  
Relative Standard

Abstract A collaborative study was conducted to evaluate the effectiveness of an immunoaffinity column cleanup liquid chromatography (LC) method for the determination of aflatoxin B1 and total aflatoxins at European regulatory limits. The test portion is extracted with methanol–water (8 + 2) for dried figs and paprika, and with methanol–water (8 + 2) plus hexane (or cyclohexane) for peanut butter and pistachios. The sample extract is filtered, diluted with phosphate buffer saline, and applied to an immunoaffinity column. The column is washed with water and the aflatoxins are eluted with methanol. Aflatoxins are quantitated by reversed-phase LC with post-column derivatization (PCD) involving bromination. PCD is achieved with either an electrochemical cell (Kobra cell) and addition of bromide to the mobile phase or pyridinium hydrobromide perbromide. Determination is by fluorescence. Peanut butter, pistachio paste, dried fig paste, and paprika powder samples, both naturally contaminated with aflatoxins and containing added aflatoxins, were sent to 16 collaborators in 16 European countries. Test portions of samples were spiked at levels of 2.4 and 9.6 ng/g for total aflatoxins which included 1.0 and 4.0 ng/g aflatoxin B1, respectively. Recoveries for total aflatoxins ranged from 71 to 92% with corresponding recoveries for aflatoxin B1 of 82 to 109%. Based on results for spiked samples (blind duplicates at 2 levels) as well as naturally contaminated samples (blind duplicates at 4 levels, including blank), the relative standard deviation for repeatability ranged from 4.6 to 23.3% for total aflatoxins and from 3.1 to 20.0% for aflatoxin B1. The relative standard deviation for reproducibility ranged from 14.1 to 34.2% for total aflatoxins, and from 9.1 to 32.2% for aflatoxin B1. The method showed acceptable within-laboratory and between-laboratory precision for all 4 matrixes, as evidenced by HORRAT values <1, at the low levels of determination for both total aflatoxins and aflatoxin B1.

Collaborative Study of a Modified Method for the Determination of Aflatoxins in Copra, Copra Meal, and Coconut

1971 ◽  
Vol 54 (4) ◽  
pp. 874-878
Author(s):  
F J Baur ◽  
J C Armstrong
Keyword(s):  
Aflatoxin B1 ◽  
Quantitative Measurement ◽  
Collaborative Study ◽  
Copra Meal ◽  
Modified Method

Abstract A collaborative study, in which 19 laboratories participated, was conducted on a modified method for the determination of aflatoxins in 2 copra samples, one naturally contaminated, and 4 samples of naturally contaminated copra meal. The sensitivity and precision of the modified method for aflatoxin B1 and total aflatoxins were comparable to the official methods for peanuts and peanut products. Aflatoxins B2, G1, and G2 were reported by most of the laboratories, but background interferences made quantitative measurement less reliable than for B1. The method as it presently stands is also applicable to the analysis of coconut. The method has been adopted as official first action; further study will be directed toward improved precision for analysis of aflatoxins B2, G1, and G2.

Multiresidue Gas Chromatographic Method for Determining Organochlorine Pesticides in Poultry Fat: Collaborative Study

1984 ◽  
Vol 67 (2) ◽  
pp. 284-289 ◽  
Author(s):  
James A Ault ◽  
Tim E Spurgeon ◽  
◽  
M M Anderson ◽  
R Bowers ◽  
...  
Keyword(s):  
Chromatographic Method ◽  
Collaborative Study ◽  
Gel Permeation Chromatography ◽  
Accuracy And Precision ◽  
Coefficients Of Variation ◽  
Poultry Fat ◽  
Gel Permeation ◽  
Detector Method ◽  
Gas Chromatographic Method

Abstract A gas chromatographic electron capture detector method is described for the quantitative determination of organochlorine pesticide residues in poultry fat. The samples are rendered and cleaned up using automated gel permeation chromatography. The collaborative samples consisted of 10 fortified samples and one incurred residue sample, all in duplicate. Fortification levels ranged from 0.15 to 1.0 ppm for a-BHC, lindane, cis- and frans-chlordane, octachlor epoxide, o,p' and p,p'-DDT, p,p'-DDE, p,p'-TDE, hexachlorobenzene, heptachlor epoxide, dieldrin, endrin, methoxychlor, mirex, and toxaphene. The average recovery was 91.9% with a range of 81-102%. The ranges of coefficients of variation were: CVo = 3.39-14.79%; CVL = 0-16.6%; and CVx = 5.82-19.0%. The results indicate accuracy and precision comparable to other official methodology. The method has been adopted official first action.

scholarly journals Determination of N-Octyl Bicycloheptene Dicarboximide, Pyrethrins, and Butylcarbityl 6-Propylpiperonyl Ether in Technical Materials, Concentrates, and Finished Products by Capillary Gas Chromatography: Collaborative Study

1998 ◽  
Vol 81 (3) ◽  
pp. 503-512 ◽  
Author(s):  
Khanh T Nguyen ◽  
Richard Moorman ◽  
Virginia Kuykendall ◽  
◽  
L Bura ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Capillary Gas Chromatography ◽  
Collaborative Study ◽  
Piperonyl Butoxide ◽  
Capillary Gc ◽  
Split Injection ◽  
Flame Ionization ◽  
Accuracy And Precision ◽  
Insecticidal Compounds

abstract Nineteen collaborating laboratories (including the authors') analyzed 6 blind, duplicate pairs of various technical materials, pyrethrum extracts, concentrates, and finished products by split injection capillary gas chromatography (GC) with flame ionization detection. This procedure simultaneously quantitates with speed, ease, accuracy, and precision all 6 insecticidal compounds in pyrethrum: pyrethrin I, jasmolin I, cinerin I, pyrethrin II, jasmolin II, and cinerin II, as well as butylcarbityl 6-propylpiperonyl ether (BPE, the predominant compound in technical piperonyl butoxide, also commonly known as piperonyl butoxide) and both the endo and exo isomers of N-octyl bicycloheptene dicarboximide (MGK 264). Repeatability ranged from 4.28 to 7.22% for total pyrethrins, from 2.41 to 7.04% for BPE, and from 2.20 to 4.91 % for total MGK 264. Reproducibility ranged from 5.22 to 9.71 % for total pyrethrins, from 4.37 to 7.04% for BPE, and from 2.66 to 6.01 % for total MGK 264. The capillary GC method for these insecticidal compounds in technical materials, concentrates, and finished products has been adopted first action by AOAC INTERNATIONAL.

Determination of Aflatoxins in Peanut Butter, Using Two Liquid Chromatographic Methods: Collaborative Study

1984 ◽  
Vol 67 (2) ◽  
pp. 312-316
Author(s):  
Alfred D Campbell ◽  
Octave J Francis ◽  
Roberta A Beebe ◽  
Leonard Stoloff ◽  
◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Peanut Butter ◽  
Collaborative Study ◽  
Normal Phase ◽  
Phase Method ◽  
Reverse Phase ◽  
Phase Liquid ◽  
Liquid Chromatographic ◽  
Packed Flow Cell

Abstract Two methods for determining aflatoxins in peanut butter, one using normal phase and the other reverse phase liquid chromatography (LC), were studied by 8 and 10 collaborators, respectively. Fluorescence detection was used for the determinative step in both methods. For reverse phase LC, aflatoxins B1 and G1 were converted to B2a and G2a; for normal phase LC, a silica gel-packed flow cell was placed in the irradiating light path of the detector. The samples included spiked and naturally contaminated peanut butter with total aflatoxin levels from about 5 to 20 ng/g and controls in a balanced pair design. For the normal phase LC method, recoveries of B1, B2, G1, and G2 from spiked samples averaged 79, 92, 74, and 88%, respectively; for the reverse phase method, the recoveries were 103, 104, 89, and 163%. For the normal phase LC method, pooled repeatabilities were 20, 23, 28, and 17% for B1, B2, G1, and G2, respectively; for the reverse phase method, the repeatabilities were 19, 22, 38, and 31%. For the normal phase method, pooled reproducibilities were 34, 33, 39, and 34% for B1, B2, G1, and G2, respectively; for the reverse phase method, the reproducibilities were 32, 46, 51, and 52%. Both methods show an improved limit of detection and better within-laboratory precision over current AOAC methods; however, between-laboratory precision is no better, and the reverse phase method shows evidence of interferences being measured. For these reasons and because of no benefits of present value, neither method was submitted for adoption as official first action.

Comparison of Methods for Determining Sodium in Fertilizers

1981 ◽  
Vol 64 (3) ◽  
pp. 704-708
Author(s):  
Luis F Corominas ◽  
Víctor M Boy ◽  
Pedro Rojas
Keyword(s):  
Phosphate Rock ◽  
Collaborative Study ◽  
Ammonium Oxalate ◽  
Selective Electrode ◽  
Accuracy And Precision ◽  
Flame Emission ◽  
Aoac Method ◽  
Aoac Official ◽  
Aas Method

Abstract The AOAC official first action method, 2.147-2.150, for flame emission spectrophotometry (FES) determination of sodium in fertilizers was compared with the atomic absorption spectrophotometric (AAS) method and the sodium selective electrode (SSE) method. Ammonium oxalate, which was previously compared with water, H2SO4, HC1, and HNO3, was used to extract the sample for all 3 methods. Three synthetic NPK samples, 3 commercial samples (urea, normal superphosphate, and neutrophos), 1 phosphate rock, and 2 Magruder check samples were used for the study. Statistically significant differences were obtained in averages for most of the samples, but few differences were found in standard deviations. The AAS method showed the best accuracy and precision. Accuracy of the AOAC method is acceptable. The SSE method showed the highest deviations from the theoretical values. A collaborative study is recommended to compare the AOAC with the AAS method.

Collaborative Study of a Method for Chemical Confirmation of the Identity of Aflatoxin

1975 ◽  
Vol 58 (1) ◽  
pp. 110-113 ◽  
Author(s):  
Michael E Stack ◽  
Albert E Pohland
Keyword(s):  
Aflatoxin B1 ◽  
Chemical Method ◽  
Peanut Butter ◽  
Collaborative Study

Abstract The chemical method for confirmation of the identity of aflatoxin by derivative formation directly on the TLC plate was studied collaboratively by 8 participants. The results show that aflatoxin B1 was confirmed in 17 of 17 sample extracts representing 15 μg aflatoxin B1/kg peanut butter, in 13 of 16 extracts representing 5 μg/kg, and in none of the 7 aflatoxin-free extracts. Collaborators commented that the method was easily performed and gave good results. The method has been adopted as official first action.

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