Collaborative Study of Three Methods for Determination of Aflatoxin in Peanuts and Peanut Products

1970 ◽  
Vol 53 (1) ◽  
pp. 104-113
Author(s):  
A E Waltking
Keyword(s):  
Peanut Butter ◽  
Collaborative Study ◽  
Method Comparison ◽  
Peanut Meal ◽  
Calibration Method ◽  
Silica Gels ◽  
Tlc Plates ◽  
Standard Calibration ◽  
Aoac Official

Abstract A collaborative study directly comparing the proposed BF method with the two AOAC official first action methods for aflatoxin in peanut products (commonly designated as the CB and t he Celite methods) was carried out on both naturally contaminated ground peanuts and specially prepared peanut butters, as well as commercial peanut butter and peanut meal to which known amounts of the anatoxins were added. Included in the study were: comparisons of a proposed variation in the CB method; a study of silica gels used for the cleanup step of the CB method; comparison of the visual and instrumental evaluation of the TLC plates; and a spectrophotometric procedure for calibration of the standards. Statistical evaluation of t h e results indicated that no advantage was obtainable through the proposed revision in the CB method nor in the use of a common silica gel lot for t h e cleanup column. The standard calibration method was shown to be both accurate and precise and instrumental evaluations of the TLC plates were shown to be more precise than visual determinations. In addition to being faster and more convenient and requiring less reagents,the BF method was equal to the official methods with respect to between-and withinlaboratory precision and accuracy.

Rapid Chemical Confirmatory Method for Aflatoxin B1. II. Collaborative Study

1970 ◽  
Vol 53 (1) ◽  
pp. 102-104
Author(s):  
L Stoloff
Keyword(s):  
Aflatoxin B1 ◽  
Peanut Butter ◽  
Collaborative Study ◽  
Peanut Meal ◽  
Official Method ◽  
Aoac Official ◽  
The Individual

Abstract A revised method for the preparation of aflatoxin B1 derivatives for chemical confirmation has been compared with the AOAC official final action method in a collaborative study, using TLC-pure aflatoxin Bi isolated by the individual collaborators from peanut butter, peanut meal, and corn. The study showed that the revised method was simpler, shorter, and more reliable than the official method. It is recommended for adoption as an official first action alternative to the preparation and observation portions of the official final action method.

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 Comparison of Babcock and Ether Extraction Methods for Determination of Fat Content of Cream: Collaborative Study

1996 ◽  
Vol 79 (4) ◽  
pp. 907-916 ◽  
Author(s):  
Joanna M Lynch ◽  
David M Barbano ◽  
J Richard Fleming
Keyword(s):  
Extraction Method ◽  
Collaborative Study ◽  
Extraction Methods ◽  
Fat Content ◽  
Official Method ◽  
Ether Extraction ◽  
Aoac Official ◽  
The Difference ◽  
Aoac Official Method

Abstract A modified Mojonnier ether extraction method for determination of the fat content of cream was developed based on the method for milk (AOAC Official Method 989.05). The cream Babcock method (AOAC Official Method 920.111 B-C) was modified to harmonize with the milk Babcock method (AOAC Official Method 989.04) and to clarify procedural details. Using the AOAC collaborative study format, 10 laboratories tested 9 pairs of blind duplicate heat-treated cream samples with a fat range of 30-45% using both methods. The statistical performance (invalid and outlier data removed) was as follows: mean % fat = 37.932, sr = 0.125, sR = 0.151, RSDr = 0.330, RSDR = 0.398, r = 0.354, and R = 0.427 for the ether extraction method. For the Babcock method, mean % fat = 38.209, sr = 0.209, SR = 0.272, RSDr = 0.548, RSDR = 0.712, r = 0.592, and R = 0.769. Average test results for fat from the Babcock method were 0.277% (absolute fat) greater than for the Mojonnier ether extraction method. The difference between methods, as a percentage of the average fat content of the samples, was 0.73%. This agrees with differences observed between the 2 methods for milk when 10 to 17 laboratories tested 7 milk samples in blind duplicate at bimonthly intervals over a 4-year period (average difference 0.029% fat, 0.78% as a percentage of average fat content). The Mojonnier ether extraction and Babcock methods for fat in cream have been adopted by AOAC INTERNATIONAL. The new Babcock method replaced the AOAC Official Method 920.111 B-C.

Potassium Interferences in Flame Emission Method for Determining Sodium in Fertilizers

1984 ◽  
Vol 67 (5) ◽  
pp. 888-889
Author(s):  
Luis F Corominas ◽  
Roberto A Navarro ◽  
Ruben J Lopez
Keyword(s):  
Analysis Of Variance ◽  
Calibration Curve ◽  
Collaborative Study ◽  
Potassium Content ◽  
Emission Method ◽  
Average Recovery ◽  
Flame Emission ◽  
Aoac Official ◽  
Preliminary Determination

Abstract Several sodium concentrations ranging from 5.2 to 20 ppm at K:Na ratios ranging from 0 to 40 were studied to determine potassium interferences in the AOAC official first action method, 2.147-2.150, for flame emission spectrophotometric (FES) determination of sodium in fertilizers. According to an analysis of variance performed with recoveries of sodium in solution, potassium interference is the same at low (5.2 ppm) or high (20 ppm) sodium concentrations but is different when the K:Na ratio is changed. A Duncan test showed that potassium interference is equivalent only in the adjacent ratios studied (0, 1, 2, 5, 10, 20, 40) and not for larger ranges. We obtained an average recovery of 98.8% using a calibration curve for a K:Na ratio from a preliminary determination with a calibration curve without potassium content. It is essential to know the potassium content of the sample to enable preparation of a calibration curve for correction. We recommend a collaborative study of NPK samples to determine whether to modify the FES method.

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.

GLC Determination of the Optical Isomers of Amphetamine

1970 ◽  
Vol 53 (1) ◽  
pp. 113-115
Author(s):  
Clyde E Wells
Keyword(s):  
Quantitative Determination ◽  
Calibration Curve ◽  
Collaborative Study ◽  
Isomeric Ratio ◽  
Dosage Forms ◽  
Optical Isomers ◽  
Standard Calibration ◽  
Tablet Dosage

Abstract A method is described for the quantitative determination of the ratio of d- and l-amphetamine stereoisomers by GLC. A derivative formed with N-trifluoroacetyl-(l)-prolyl chloride is chromatographed and the isomeric ratio is read from a standard calibration curve. The method is applicable to crystalline salts of amphetamine and to commercial tablet dosage forms. It is recommended that this method be subjected to collaborative study.

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.

Evaluation of Agreement Among Routine Methods for Determination of Fluoride in Vegetation: Interlaboratory Collaborative Study

1982 ◽  
Vol 65 (5) ◽  
pp. 1150-1154
Author(s):  
Jay S Jacobson ◽  
John J Troiano ◽  
Christina C Cosentini ◽  
John Evans
Keyword(s):  
Significant Interaction ◽  
Collaborative Study ◽  
Considerable Improvement ◽  
The Other ◽  
Mean Values ◽  
Potentiometric Analysis ◽  
Aoac Official ◽  
Vegetation Samples ◽  
Action Methods

Abstract An interlaboratory collaborative study was conducted to evaluate the performance of methods and laboratories for the measurement of fluoride in vegetation. Samples of 8 plant species containing about 5-200 ppm fluoride were distributed to 40 participants who were instructed to use their routine methods of analysis. Methods which had sufficient participants to allow the inclusion of results in statistical analyses were classified into 3 categories: (1) Willard-Winter method (similar to the AOAC official final action method); (2) semiautomated and potentiometric methods (similar to the 2 AOAC official first action methods); and (3) potentiometric analysis with prior ashing, fusion, and/or distillation (not an approved method). There was a significant interaction of methods with samples caused by 3 of the 8 samples. In the other 5 samples, the Willard-Winter and semiautomated methods gave higher mean values for fluoride content than did the 2 potentiometric methods. Despite considerable improvement in speed and simplicity of fluoride analyses during the last decade, agreement between laboratories has not improved because of the variety of methods and techniques in use, the inherent differences between methods, and, apparently, poor laboratory quality control.

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.

scholarly journals Determination of Trace and Heavy Metals in Fruit Juices in the Romanian Market

2020 ◽  
Vol 77 (2) ◽  
pp. 125
Author(s):  
Florin Dumitru BORA ◽  
Anamaria CĂLUGĂR ◽  
Claudiu Ioan BUNEA ◽  
Ionut RACZ
Keyword(s):  
Heavy Metals ◽  
Calibration Method ◽  
Fruit Juices ◽  
Trace Heavy Metals ◽  
Icp Ms ◽  
Metal Contents ◽  
External Standard ◽  
Standard Calibration ◽  
Peach Juice

The presence of trace, heavy metals in foodstuffs is of intense public interest. The aim of this study was to determine the metal contents in most known commercial fruit juices present on the Romanian market. The multielement analysis was made using the ICP-MS technique, after appropriate dilution, using the external standard calibration method. Multifruit, mango, and kiwi juice have recoded the highest concentration of Cu, while apple and pear juice has recoded the lowest concentration, and in the case of Zn, peach juice has recoded the highest concentration. Concerning Pb, Cd, and As concentration, apple, peach, and multifruit juices recorded the highest levels of concentration. The concentration of Zn, Cu, Co, and As generally, was higher in the juice samples packed in boxes, while Ni, Cr, Pb, and Cd recorded the highest values in the juice packed in plastic bottles.

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