Determination of Aflatoxin B1 in Corn, Wheat, and Peanut Butter by Enzyme-linked Immunosorbent Assay and Solid Phase Radioimmunoassay

1981 ◽  
Vol 64 (5) ◽  
pp. 1077-1082 ◽  
Author(s):  
Ossama El-Nakib ◽  
James J Pestka ◽  
Fun S Chu
Keyword(s):  
Aflatoxin B1 ◽  
Solid Phase ◽  
Peanut Butter ◽  
Extraction Procedure ◽  
Tween 20 ◽  
Enzyme Linked Immunosorbent Assay ◽  
Coefficients Of Variation ◽  
Solid Phase Radioimmunoassay ◽  
Phosphate Buffered Saline

Abstract Determinations of aflatoxin B1 in corn, wheat, and peanut butter by an enzyme-linked immunoassay (ELISA) and a solid-phase radioimmunoassay (RIA) were compared. Samples spiked with 2.9-43.2 ppb B1 were subjected to AOAC extraction procedure 26.017 or 26.023. The extracts were concentrated, redissolved in methanol, diluted in phosphate-buffered saline with Tween 20, and directly analyzed for B1 by either ELISA or RIA. At 5.8 ppb or greater, recoveries for B1 in corn, wheat, and peanut butter samples were 80.0,86.6, and 94.8% by ELISA and 61.0, 93.3, and 110.0% by RIA, respectively. Recoveries greater than 120% were obtained for the wheat and peanut butter samples spiked with 2.9 ppb aflatoxin B1 by the RIA method but not by ELISA. Overall results indicated that ELISA gave more consistent data, relatively lower standard deviations, and lower coefficients of variation than did RIA. Analysis of 3 samples naturally contaminated with aflatoxins revealed that the ELISA data were comparable to those obtained by other established chemical methods.

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.

Determination of sterigmatocystin in beer by high performance liquid chromatography with ultraviolet detection

2008 ◽  
Vol 1 (2) ◽  
pp. 161-166 ◽  
Author(s):  
A. Veršilovskis ◽  
S. De Saeger ◽  
V. Mikelsone
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Solid Phase ◽  
Extraction Procedure ◽  
Reversed Phase ◽  
Ultraviolet Detection ◽  
Coefficients Of Variation ◽  
Solid Phase Extraction Procedure

A new method for the determination of sterigmatocystin in beer was developed. This method consists of a solid phase extraction procedure of light and dark beer and reversed phase high performance liquid chromatography with ultraviolet detection. Recoveries of sterigmatocystin from beer samples spiked at levels from 0.5 to 100 µg/l ranged from 81 to 126% for light beer and from 88 to 126% for dark beer with coefficients of variation between 2.2 and 14%. From the total of 26 analysed Latvian beer samples only two (7.7%) were contaminated with sterigmatocystin.

Indirect Enzyme-Linked Immunosorbent Assay for Detection of Aflatoxin B1 in Corn and Peanut Butter

1984 ◽  
Vol 47 (4) ◽  
pp. 263-266 ◽  
Author(s):  
TITAN S.L. FAN ◽  
FUNS. CHU
Keyword(s):  
Immunosorbent Assay ◽  
Aflatoxin B1 ◽  
Solid Phase ◽  
Peanut Butter ◽  
Enzyme Linked Immunosorbent Assay ◽  
Corn Meal ◽  
Additional Advantage ◽  
Microtiter Plates ◽  
Sample Extract ◽  
Direct Elisa

An indirect enzyme-linked immunosorbent assay (ELISA) for aflatoxin B1 (AFB1) was developed. The method involves coating AFB1-polylysine conjugate on microtiter plates as immobilized antigen, followed by incubation with free toxin standard or sample extract and anti-aflatoxin antibody from rabbits. The amount of antibody bound to the solid phase was determined by subsequent incubation with a secondary antibody conjugated with an enzyme, i.e., goat anti-rabbit IgG-horseradish peroxidase conjugate, and reaction with the chromogenic substrate. Aflatoxins were extracted from peanut butter and corn meal samples according to the BF and CB method of the Association of Official Analytical Chemists, respectively. Extracts without column cleanup treatment were dissolved in assay buffer for subsequent ELISA. Using this technique, 79.5 to 98.6% and 68 to 97% of AFB1 added in the range of 5 to 40 (μg/kg to the corn meal and peanut butter samples were recovered, respectively. The indirect ELISA achieved the same sensitivity and specificity for AFB1 as that obtained from the direct ELISA, with an additional advantage that much less antibody (100 times less) was required for the assay.

scholarly journals A Case for Regular Aflatoxin Monitoring in Peanut Butter in Sub-Saharan Africa: Lessons from a 3-Year Survey in Zambia

2016 ◽  
Vol 79 (5) ◽  
pp. 795-800 ◽  
Author(s):  
SAMUEL M. C. NJOROGE ◽  
LIMBIKANI MATUMBA ◽  
KENNEDY KANENGA ◽  
MOSES SIAMBI ◽  
FARID WALIYAR ◽  
...  
Keyword(s):  
South Africa ◽  
Aflatoxin B1 ◽  
Peanut Butter ◽  
Aflatoxin Contamination ◽  
Comprehensive Analysis ◽  
Sub Saharan Africa ◽  
Enzyme Linked Immunosorbent Assay ◽  
Contamination Level ◽  
Batch Number ◽  
Sub Saharan

ABSTRACT A 3-year comprehensive analysis of aflatoxin contamination in peanut butter was conducted in Zambia, sub-Saharan Africa. The study analyzed 954 containers of 24 local and imported peanut butter brands collected from shops in Chipata, Mambwe, Petauke, Katete, and Nyimba districts and also in Lusaka from 2012 to 2014. For analysis, a sample included six containers of a single brand, from the same processing batch number and the same shop. Each container was quantitatively analyzed for aflatoxin B1 (AFB1) in six replicates by using competitive enzyme-linked immunosorbent assay; thus, aflatoxin contamination level of a given sample was derived from an average of 36 test values. Results showed that 73% of the brands tested in 2012 were contaminated with AFB1 levels >20 μg/kg and ranged up to 130 μg/kg. In 2013, 80% of the brands were contaminated with AFB1 levels >20 μg/kg and ranged up to 10,740 μg/kg. Compared with brand data from 2012 and 2013, fewer brands in 2014, i.e., 53%, had aflatoxin B1 levels >20 μg/kg and ranged up to 1,000 μg/kg. Of the eight brands tested repeatedly across the 3-year period, none consistently averaged ≤20 μg/kg. Our survey clearly demonstrates the regular occurrence of high levels of AF B1 in peanut butter in Zambia. Considering that some of the brands tested originated from neighboring countries such as Malawi, Zimbabwe, and South Africa, the current findings provide a sub-Saharan regional perspective regarding the safety of peanut butter.

Simultaneous Determination of Aflatoxin B1 and Aflatoxin M1 in Food Matrices by Enzyme-Linked Immunosorbent Assay

2012 ◽  
Vol 6 (3) ◽  
pp. 767-774 ◽  
Author(s):  
Wenxiao Jiang ◽  
Zhanhui Wang ◽  
Greta Nölke ◽  
Jing Zhang ◽  
Lanlan Niu ◽  
...  
Keyword(s):  
Simultaneous Determination ◽  
Immunosorbent Assay ◽  
Aflatoxin B1 ◽  
Aflatoxin M1 ◽  
Enzyme Linked Immunosorbent Assay ◽  
Food Matrices

Direct solid-phase enzymoimmunoassay of testosterone in saliva.

1989 ◽  
Vol 35 (10) ◽  
pp. 2044-2047 ◽  
Author(s):  
K Howard ◽  
M Kane ◽  
A Madden ◽  
J P Gosling ◽  
P F Fottrell
Keyword(s):  
Detection Limit ◽  
Analytical Procedure ◽  
Solid Phase ◽  
Medical Applications ◽  
Microtiter Plates ◽  
Large Numbers ◽  
Coefficients Of Variation ◽  
Serial Sampling ◽  
Direct Solid

Abstract This competitive, solid-phase enzymoimmunoassay for testosterone in saliva is carried out on microtiter plates and involves no chromatographic or extraction steps. With an overnight incubation the detection limit of the assay is 230 fg per well (16.1 pmol/L). There was a good correlation (correlation coefficient 0.95) between testosterone concentrations measured with and without prior extraction of the saliva samples. Repeated assay of three control saliva samples containing a range of testosterone concentrations (200-1000 pmol/L) gave within- and between-assay coefficients of variation of 5.5-13.2%. The analytical procedure is simple and closely resembles already published procedures for the determination of progesterone and estrone (with extraction) in saliva. One person can assay 200 samples in 24 h and the assay is suitable for reproductive and sports medical applications, particularly for projects involving serial sampling and yielding large numbers of samples.

A solid-phase enzymeimmunoassay for the determination of progesterone in bovine, porcine and ovine plasma

1995 ◽  
Vol 75 (4) ◽  
pp. 525-529 ◽  
Author(s):  
R. P. Del Vecchio ◽  
W. D. Sutherland ◽  
M. L. Connor
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Petroleum Ether ◽  
Bovine Serum ◽  
Solid Phase ◽  
Plasma Samples ◽  
Assay Sensitivity ◽  
Coefficients Of Variation ◽  
Rabbit Igg

The purpose of this project was to develop a valid quantitative enzymeimmunoassay (EIA) for progesterone in blood plasma of cattle, pigs and sheep. Rabbit anti-progesterone, mouse monoclonal anti-rabbit IgG, authentic progesterone, and acetylcholine esterase bound covalently to progesterone were the principal reagents used to develop the EIA. Ninety-six well microliter plates were coated with mouse monoclonal anti-rabbit IgG and saturated with bovine serum albumin before use. Rabbit anti-progesterone was diluted to a working dilution of 1:2.0 × 106. Standard curves were linear and ranged from 1.56 to 400 pg of progesterone per well which allowed for the measurement of 0.03125 to 8.0 ng mL−1. Assay sensitivity averaged 1.56 pg well−1. Progesterone was extracted from plasma samples with petroleum ether. Plasma samples (n = 3 or 4 from each species) with unknown amounts of progesterone that were extracted and serially diluted with EIA buffer did not deviate from parallelism with progesterone standard curves in buffer. The correlation between EIA and radioimmunoassay (RIA) measurements of progesterone in the same plasma samples was high (P < 0.0001) for all three species (r = 0.96 for bovine; r = 0.96 for porcine; r = 0.94 for ovine). The regression of EIA data on RIA data produced the following equations:[Formula: see text]The intra- and inter-assay coefficients of variation were 5.4 and 10.6% for bovine, 5.8 and 11.0% for porcine and, 6.1 and 12.3% for ovine, respectively. These data show that this EIA is a valid and reliable memod for quantitating progesterone in extracts of bovine, porcine and ovine plasma. Key words: Enzymeimmunoassay, progesterone, plasma, bovine, porcine, ovine

Solid-phase radioimmunoassay for morphine, with use of an affinity-purified morphine antibody.

1978 ◽  
Vol 24 (2) ◽  
pp. 339-342 ◽  
Author(s):  
M Steiner ◽  
J L Spratt
Keyword(s):  
Affinity Chromatography ◽  
Correlation Coefficient ◽  
Solid Phase ◽  
Rapid Determination ◽  
Biological Fluids ◽  
Inhibitory Effect ◽  
Major Metabolite ◽  
Solid Phase Radioimmunoassay ◽  
Related Compounds

Abstract Morphine antibody purified by affinity chromatography was used to develop a solid-phase radioimmunoassay for morphine in polystyrene tubes. The tubes are coated with an appropriate concentration of the purified antibody, rinsed three times with buffered saline, and stored at -15 degrees C. Using tritiated dihydromorphine, we determined competitive morphine binding by difference when the radioactivity in the assay supernates was measured after incubation (1 h, 37 degrees C). Five standard curves, with use of serum equivalents of morphine ranging from 0 to 6 mug/liter, were linear and had a mean correlation coefficient of 0.98. Uncer conditions of the assay, levorphanol was comparable to morphine in its inhibitory effect on binding of labeled dihydromorphine, whereas dextrorphan was essentially inactive. Morphine-3-glucuronide, a major metabolite, is 55-fold less inhibitory in terms of its capacity to displace the radiolabel. We believe that the sensitivity of the technique, coupled with the simplicity of nonseparatory sampling, renders the system suitable for rapid determination of morphine and related compounds in biological fluids.

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