scholarly journals An Immunoaffinity Column for the Determination of Peanut Protein in Chocolate

1999 ◽  
Vol 82 (3) ◽  
pp. 666-668 ◽  
Author(s):  
Harvey W Newsome ◽  
Michael Abbott
Keyword(s):  
Detection Limit ◽  
Immunoaffinity Chromatography ◽  
Polyclonal Antiserum ◽  
Peanut Protein ◽  
Enzyme Linked Immunosorbent Assay ◽  
Immunoaffinity Column ◽  
Rabbit Polyclonal Antiserum ◽  
The Matrix ◽  
Direct Elisa

Abstract An immunoaffinity column was prepared from rabbit polyclonal antiserum for the determination of peanut protein from food matrixes. The anti-peanut immunoglobulin G was isolated from antiserum by affinity chromatography on a column coupled with peanut protein and then attached to an AminoLink gel. The column was applied to the determination of peanut protein in chocolate after extraction, immunoaffinity chromatography, and enzyme-linked immunosorbent assay (ELISA). Overall recoveries from chocolate spiked with 0.2–3.2 μg/g of peanut protein averaged 77% (range, 72–84%), and the minimum detection limit was 0.1 μg/g. Chromatography of extracts with the column improved detection limit and eliminated the matrix effect experienced with direct ELISA of chocolate extracts.

Determination of Ochratoxin A in Feed by Immunoaffinity Cleanup and Liquid Chromatography

2013 ◽  
Vol 96 (3) ◽  
pp. 599-602 ◽  
Author(s):  
Ping Ding ◽  
Ziyou Mi ◽  
Yali Hou ◽  
Yigang He ◽  
Jianhua Xie
Keyword(s):  
Liquid Chromatography ◽  
Detection Limit ◽  
Ochratoxin A ◽  
Cyanogen Bromide ◽  
Polyclonal Antibodies ◽  
Immunoaffinity Column ◽  
Low Levels ◽  
Sepharose 4B ◽  
Feed Samples

Abstract A method using LC was developed for determination of ochratoxin A (OTA) in feeds. The extracted samples were cleaned up by an immunoaffinity column prepared by covalently coupling polyclonal antibodies against OTA to cyanogen bromide-activated Sepharose 4B. The eluates were determined by LC with fluorescence detection. Recoveries of OTA from fortified samples of 1–10 μg/kg levels ranged from 84.3 to 90.0%, with CVs of 3.3–7.8%. The detection limit was 0.045 μg/kg based on an S/N of 3:1. A total of 65 feed samples were screened for OTA with the proposed method. The results showed that only nine samples were contaminated with OTAs at low levels. The presented method was successfully applied to quantify OTAs in real feed samples.

scholarly journals ELISA for Determination of Human Growth Hormone: Recognition of Helix 4 Epitopes

2004 ◽  
Vol 2004 (3) ◽  
pp. 143-149 ◽  
Author(s):  
Juliana F. Moura ◽  
Luiz DeLacerda ◽  
Romolo Sandrini ◽  
Fernanda M. Borba ◽  
Denise N. Castelo ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Human Growth Hormone ◽  
Synthetic Peptide ◽  
Human Growth ◽  
Cross Reactivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Immunoaffinity Column ◽  
Receptor Dimerization ◽  
Human Prolactin

Human growth hormone (hGH) signal transduction initiates with a receptor dimerization in which one molecule binds to the receptor through sites 1 and 2. A sandwich enzyme-linked immunosorbent assay was developed for quantifying hGH molecules that present helix 4 from binding site 1. For this, horse anti-rhGH antibodies were eluted by an immunoaffinity column constituted by sepharose-rhGH. These antibodies were purified through a second column with synthetic peptide correspondent tohGH helix 4, immobilized to sepharose, and used as capture antibodies. Those that did not recognize synthetic peptide were used as a marker antibody. The working range was of 1.95 to 31.25 ng/mL of hGH. The intra-assay coefficient of variation (CV) was between 4.53% and 6.33%, while the interassay CV was between 6.00% and 8.27%. The recovery range was between 96.0% to 103.8%. There was no cross-reactivity with human prolactin. These features show that our assay is an efficient method for the determination of hGH.

Determination of Deoxynivalenol in Wheat-Based Breakfast Cereals Marketed in Portugal

2001 ◽  
Vol 64 (11) ◽  
pp. 1848-1850 ◽  
Author(s):  
MARIA LÍGIA MARTINS ◽  
H. MARINA MARTINS
Keyword(s):  
Liquid Chromatography ◽  
Detection Limit ◽  
Natural Occurrence ◽  
Fungal Metabolites ◽  
Immunoaffinity Column ◽  
Breakfast Cereals ◽  
Average Recovery ◽  
Genus Fusarium ◽  
Natural Contamination

Deoxynivalenol (DON), also known as vomitoxin, is one of a group of closely related secondary fungal metabolites—the trichothecenes—and is produced predominantly by several species of the genus Fusarium, especially Fusarium graminearum. The present study was carried out to evaluate the natural occurrence of DON in different kinds of wheat-based breakfast cereals widely consumed by the population. A total of 88 commercially available samples of wheat-based breakfast cereals were randomly collected from different supermarkets in Lisbon, Portugal. The samples were analyzed using immunoaffinity column, and DON was quantified by liquid chromatography. Detection limit was 100 μg/kg. Average recovery of DON was 80%. Of 88 analyzed samples, 72.8% contained levels of DON between 103 and 6,040 μg/kg, with mean level of 754 μg/kg, and 24 samples (27.2%) were not contaminated (<100 μg/kg). These results indicate an incidence of this mycotoxin in these products, and the authors suggest a monitoring for the prevention of molds and mycotoxins. This is the first report in Portugal on natural contamination with DON in wheat-based breakfast cereals.

Development of an Analytical Protocol for the Determination of Polybrominated Biphenyls in Water by Enzyme-Linked Immunosorbent Assay

2011 ◽  
Vol 347-353 ◽  
pp. 1537-1541 ◽  
Author(s):  
Han Yu Chen ◽  
Hui Sheng Zhuang
Keyword(s):  
Detection Limit ◽  
Quantitative Determination ◽  
Incubation Time ◽  
Polyclonal Antibodies ◽  
Enzyme Linked Immunosorbent Assay ◽  
Antibody Concentration ◽  
Polybrominated Biphenyls ◽  
Analytical Protocol ◽  
Optimized Conditions

A novel immunoassay has been developed for the quantitative determination of polybrominated biphenyls (PBBs) using indirect competitive format. A new method was developed to synthesize PBBs congener (PCB15) hapten and its artificial immunogen, then the polyclonal antibodies. The assay was optimized concerning the coating conjugate and antibody concentration, incubation time and temperature, the tolerance to organic solvents and so on. Under optimized conditions, PBB15 can be determined in the concentration range of 0.01-100 μg L-1 with a detection limit of 0.02 μg L-1. The cross-reactivities of the assays were below 8%. While water samples could be analyzed directly.

scholarly journals Determination of Egg Proteins in Food Products by Enzyme Immunoassay

2000 ◽  
Vol 83 (1) ◽  
pp. 139-143 ◽  
Author(s):  
Jupiter M Yeung ◽  
W Harvey Newsome ◽  
Michael A Abbott
Keyword(s):  
Detection Limit ◽  
Enzyme Immunoassay ◽  
Polyclonal Antibodies ◽  
Enzyme Linked Immunosorbent Assay ◽  
Antigen Binding ◽  
Food Ingredients ◽  
Coefficients Of Variation ◽  
Egg Products ◽  
Whole Egg

Abstract An enzyme-linked immunosorbent assay (ELISA) was developed to determine the presence of egg proteins in foods. The polyclonal antibodies developed were specific to whole egg proteins and did not cross-react with any of the 38 nuts, legumes, or other common food ingredients tested. The concentrations of egg proteins that will inhibit 50% of antibody–antigen binding, IC50, were 3–7 ng/mL, and the linear range was 0.5–62.5 ng/mL. The detection limit was 0.2 ppm for various foods. Recoveries ranged from 67 to 96%. The intra- and inter-assay coefficients of variation in this procedure were 10–13% for ice cream spiked at 0.8 and 1.6 ppm. The ELISA has been applied to ice creams, noodles, pasta, and breads. Egg proteins were identified in all declared egg products, and no false positives were found.

Headspace Gas Chromatographic Method for Determination of Methyl Bromide in Food Ingredients

1985 ◽  
Vol 68 (6) ◽  
pp. 1112-1116
Author(s):  
Jonathan W DeVries ◽  
James M Broge ◽  
John P Schroeder ◽  
Raymond H Bowers ◽  
Paul A Larson ◽  
...  
Keyword(s):  
Detection Limit ◽  
Methyl Bromide ◽  
Chromatographic Method ◽  
Equilibration Time ◽  
Gas Chromatograph ◽  
Food Ingredients ◽  
Headspace Gas ◽  
The Matrix ◽  
Gas Chromatographic Method

Abstract A headspace gas chromatographic (GC) method, which can be automated, has been developed for determination of methyl bromide. This method has been applied to wheat, flour, cocoa, and peanuts. Samples to be analyzed are placed in headspace sample vials, water is added, and the vials are sealed with Teflon-lined septa. After an appropriate equilibration time at 32°C, the samples are analyzed within 10 h. A sample of the headspace is withdrawn and analyzed on a gas chromatograph equipped with an electron capture detector (ECD). Methyl bromide levels were quantitated by comparison of peak area with a standard. The standard was generated by adding a known amount of methyl bromide to a portion of the matrix being analyzed and which was known to be methyl bromide free. The detection limit of the method was 0.4 ppb. The coefficient of variation (CV) was 6.5% for wheat, 8.3% for flour, 3.3% for cocoa, and 11.6% for peanuts.

Light-chain ratios of immunoglobulins G, A, and M determined by enzyme immunoassay

1990 ◽  
Vol 36 (3) ◽  
pp. 501-502 ◽  
Author(s):  
S H Chui ◽  
C W Lam ◽  
K N Lai
Keyword(s):  
Hydrogen Peroxide ◽  
Detection Limit ◽  
Light Chain ◽  
Reference Intervals ◽  
Light Chains ◽  
Enzyme Linked Immunosorbent Assay ◽  
Microtiter Plates ◽  
Urea Hydrogen Peroxide ◽  
Apparently Healthy

Abstract We describe an enzyme-linked immunosorbent assay for determination of light-chain ratios for IgG, IgA, and IgM in serum. A commercial serum with known overall kappa and lambda concentrations was used as standard. To capture the respective immunoglobulins, we used antibodies to gamma, lambda and mu chains coated onto microtiter plates. Peroxidase-conjugated anti-kappa and anti-lambda chain antisera were reacted with light chains on the captured immunoglobulins, and the amount of enzyme bound was monitored with o-phenylenediamine and urea-hydrogen peroxide as substrates. Calculation of absorbance ratios allowed determination of kappa and lambda chain concentrations of individual immunoglobulins in the standard and samples. Within-run and between-run CVs (n = 25) ranged from 5.9% to 13.0% for "high," "normal," and "low" kappa/lambda ratios for IgG, IgA, and IgM. The thoroughness of light-chain detection, expressed as, e.g., (IgA kappa + IgA lambda)/(total IgA), for 150 sera was 91-110%. The detection limit was 1 microgram/L. Reference intervals (mean +/- SD) for kappa/lambda ratios in sera from 100 apparently healthy adults were 2.34 +/- 0.80 for IgG, 1.59 +/- 0.40 for IgA, and 1.86 +/- 0.76 for IgM.

Enzyme-Linked Immunosorbent Assay for T-2 Toxin Metabolites in Urine

1989 ◽  
Vol 72 (2) ◽  
pp. 345-348
Author(s):  
Rachel C Lee ◽  
Ru-Dong Wei ◽  
Fun S Chu
Keyword(s):  
Immunosorbent Assay ◽  
Cross Reactivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Linear Portion ◽  
Standard Curve ◽  
Sample Extract ◽  
Direct Elisa ◽  
Minimum Detection Level ◽  
Elisa Plate

Abstract A direct competitive enzyme-linked immunosorbent assay (ELISA) for determination of total T-2 toxin metabolites in urine was developed. The assay involves coating anti-3-acetyl-neosolaniol-hemisuccinate- bovine serum albumin conjugate (anti-3-Ac-NEOS-HS-BSA) antibody to the ELISA plate and using 3-Ac-NEOS-HS-peroxidase as the enzyme marker. Competitive ELISA revealed that the antibody had good cross-reactivity with acetyldiacetoxyscirpenol (Ac-DAS), T-2 tetraol tetraacetate, 3'-OH-Ac-T-2, 3-Ac-NEOS, and 3,4,15- triacetyl-12,13-epoxytrichothec-9-en-8-one (Ac-T-2-8-one), but less cross-reactivity with Ac-T-2 toxin and T-2 toxin. All metabolites of T-2 toxin in urine were converted to T-2 tetraol tetraacetate (T-2- 4ol-4Ac) by acetylation of the sample extract before ELISA. To test the ELISA accuracy, a radioimmunoassay (RIA) was performed simultaneously. The linear portion of the standard curve of this direct ELISA for T-2-4ol-4Ac was 0.2-2.0 ng/mL, which was 10 times more sensitive than RIA. The minimum detection level for T-2-4ol- 4Ac was 0.02 ng/mL (0.4 pg/assay) in the absence of urine sample. The overall analytical recoveries for T-2 toxin, HT-2, T-2-4ol, 3'- OH-HT-2, NEOS, and a mixture of these 5 toxins added to the urine samples in the ELISA at concentrations of 0.05 and 0.2 ng/mL were 87 and 94%, respectively.

Enzyme-Linked Immunosorbent Assay for the Determination of Five Organophosphorus Pesticides in Camellia Oil

2014 ◽  
Vol 77 (7) ◽  
pp. 1178-1183 ◽  
Author(s):  
YIHUA LIU ◽  
YIRONG GUO ◽  
GUONIAN ZHU ◽  
FUBIN TANG
Keyword(s):  
Immunosorbent Assay ◽  
Solid Phase ◽  
Organophosphorus Pesticides ◽  
Enzyme Linked Immunosorbent Assay ◽  
Regulatory Requirements ◽  
Camellia Oil ◽  
The Matrix ◽  
Interassay Coefficient ◽  
Assay Conditions

A matrix solid-phase dispersion and direct competitive enzyme-linked immunosorbent assay (MSPD-ELISA) was developed for five organophosphorus pesticides (OPs) in camellia oil. Seven haptens with different substituents in the aromatic ring were used to prepare different competitors; the ELISA showed highest sensitivity and specificity to OPs when the competitor had moderate heterology to the immunizing hapten. Several assay conditions were optimized to increase the ELISA sensitivity. The optimized ELISA for five OPs had 50% inhibitory concentrations of 6.3 ng/ml (parathion), 18.9 ng/ml (methyl parathion), 120.7 ng/ml (fenitrothion), 110.4 ng/ml (fenthion), and 20.7 ng/ml (phoxim). The average recoveries of five OPs in camellia oil ranged from 75.7 to 105.3%, with the interassay coefficient of variations ranging from 6.0 to 13.4%. Compared with the results previously reported, the ELISA that was developed in the present study showed a much higher sensitivity. Additionally, MSPD was used in the sample preparation to minimize the matrix effect. Recoveries from the method developed here were in agreement with those obtained by gas chromatography, which indicated that the detection performance of the MSPD-ELISA could meet the regulatory requirements of different governments and international organizations.

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