scholarly journals Determination of Biotin and Folate in Infant Formula and Milk by Optical Biosensor-Based Immunoassay

2000 ◽  
Vol 83 (5) ◽  
pp. 1141-1148 ◽  
Author(s):  
Harvey E Indyk ◽  
Eileen A Evans ◽  
Malin C Bostrom Caselunghe ◽  
Bjorn S Persson ◽  
Paul M Finglas ◽  
...  
Keyword(s):  
Interaction Analysis ◽  
Automated Analysis ◽  
Optical Biosensor ◽  
Cross Reactivity ◽  
Biomolecular Interaction ◽  
Technology Standard ◽  
Sample Extraction ◽  
Relative Standard ◽  
Assay Methods

Abstract Biomolecular interaction analysis was evaluated for the automated analysis of biotin- and folate-supplemented infant formulas and milk powders. The technique was configured as a biosensor-based, nonlabeled inhibition immunoassay using monoclonal antibodies raised against analyte-conjugate. Sample extraction conditions were optimized and antibodies were evaluated for cross-reactivity. Performance parameters included a quantitation range of 2–70 ng/mL, recoveries of 86–102%, agreement against assigned reference values for National Institute of Standards and Technology Standard Reference Material 1846, between-laboratory reproducibility relative standard deviation of 9.1% for biotin and 8.1% for folate, respectively, and equivalence against reference microbiological assay methods for both analytes.

scholarly journals Determination of Vitamin B12 in Milk Products and Selected Foods by Optical Biosensor Protein-Binding Assay: Method Comparison

2002 ◽  
Vol 85 (1) ◽  
pp. 72-81 ◽  
Author(s):  
Harvey E Indyk ◽  
Bjorn S Persson ◽  
Malin C B Caselunghe ◽  
Anna Moberg ◽  
Enrico L Filonzi ◽  
...  
Keyword(s):  
Protein Binding ◽  
Vitamin B12 ◽  
Binding Assay ◽  
Interaction Analysis ◽  
Optical Biosensor ◽  
Assay Method ◽  
Analytical Technique ◽  
Protein Binding Assay ◽  
Relative Standard

Abstract Biomolecular interaction analysis was evaluated for the automated determination of vitamin B12 in a range of foods. The analytical technique was configured as a biosensor-based, nonlabeled inhibition protein-binding assay using nonintrinsic R-protein. Sample extraction conditions were optimized, and both ligand specificity and nonspecific binding considerations were evaluated. Performance parameters included a quantitation range of 0.08–2.40 ng/mL, recoveries of 89–106%, agreement against assigned reference values for 3 independent certified food reference materials, and a mean between-laboratory reproducibility relative standard deviation of 4.9%. The proposed method was compared with reference microbiological and radioisotope protein-binding methods for a range of food samples. A wide selection of milks, infant formulas, meats, and liver were evaluated for their vitamin B12 content. The influence of season was studied in herd milk, early lactation was followed for a single animal, and the cobalamin content of bovine, caprine, and ovine milks was compared.

scholarly journals Single-Laboratory Validation of the Biosense Direct Competitive Enzyme-Linked Immunosorbent Assay (ELISA) for Determination of Domoic Acid Toxins in Shellfish

2007 ◽  
Vol 90 (4) ◽  
pp. 1000-1010 ◽  
Author(s):  
Hans Kleivdal ◽  
Sven-Inge Kristiansen ◽  
Mona V Nilsen ◽  
Lyn Briggs
Keyword(s):  
Immunosorbent Assay ◽  
Domoic Acid ◽  
Matrix Effects ◽  
Limit Of Detection ◽  
Method Comparison ◽  
Cross Reactivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Shellfish Poisoning ◽  
Relative Standard

Abstract Method validation was conducted for an enzyme-linked immunosorbent assay (ELISA) for the determination of domoic acid (DA) toxins, known to give amnesic shellfish poisoning (ASP) symptoms, in shellfish. The calibration curve range of the assay is approximately 10260 pg/mL, with a dynamic working range for DA toxins in shellfish from 0.01 to at least 250 mg/kg. The ASP ELISA showed no significant cross-reactivity to structural analogs, and proved to be robust to deliberate alterations of the optimal running conditions. The shellfish matrix effects observed with mussels, oysters, and scallops were eliminated by diluting shellfish extracts 1:200 prior to analysis, leading to a limit of detection at 0.003 mg/kg. Thirteen blank shellfish homogenates were spiked with certified mussel material containing DA to levels in the range of 0.125 mg DA/kg, and analyzed in quadruplicate on 3 different days. The relative standard deviation (RSD) under intra-assay repeatability conditions ranged from 6.5 to 13.1%, and under interassay repeatability conditions the RSD ranged from 5.7 to 13.4%, with a mean value of 9.3%. The recoveries ranged from 85.5 to 106.6%, with a mean recovery of 102.2%. A method comparison was conducted with liquid chromatography with ultraviolet detection, using naturally contaminated scallop samples (n = 27) with DA levels at 0244 mg/kg. The overall correlation coefficient was 0.960 and the slope of the regression was 1.218, indicating a good agreement between the methods.

scholarly journals Determination of Pantothenic Acid in Foods by Optical Biosensor Immunoassay

2005 ◽  
Vol 88 (4) ◽  
pp. 1008-1014 ◽  
Author(s):  
Simon A Haughey ◽  
Anthony A O'Kane ◽  
G Andrew Baxter ◽  
Andras Kalman ◽  
Marie-José Trisconi ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Extraction Procedure ◽  
Pantothenic Acid ◽  
Optical Biosensor ◽  
Liquid Chromatography Mass Spectrometry ◽  
Relative Standard ◽  
Wide Range ◽  
Simple Extraction ◽  
Reference Samples

Abstract An optical biosensor inhibition immunoassay was developed using a specific pantothenic acid-binding protein for the quantitation of free pantothenic acid (vitamin B5) in foodstuffs. Samples were prepared by a simple extraction procedure in buffer, and vitamin content was estimated against authentic calibrants in the same buffer. Performance parameters included a working range of 10–5000 ng/mL, a limit of detection of 4.4 ng/mL, precision relative standard deviation of 5.4–7.1% over a range of concentrations, and recoveries >95% in the matrixes tested. A wide range of foodstuffs, including National Institute of Standards and Technology reference samples, were tested in 3 independent laboratories and the results were compared with microbiological assay and liquid chromatography/mass spectrometry (LC/MS) methods. The results indicate that the biosensor technique is appropriate for the estimation of pantothenic acid in a wide range of foodstuffs.

scholarly journals The Validation of Neogen Reveal® Q+ for DON

2020 ◽  
Vol 103 (1) ◽  
pp. 176-183
Author(s):  
R Lucas Gray ◽  
Alex Kostin ◽  
Gabrielle Anderson ◽  
Brooke Roman ◽  
Frank Klein ◽  
...  
Keyword(s):  
Reference Values ◽  
Brown Rice ◽  
Cross Reactivity ◽  
Aqueous Sample ◽  
Test Results ◽  
Independent Laboratory ◽  
Sample Extraction ◽  
Reliable Performance ◽  
Expiration Dating

Abstract Background: Reveal® Q+ for DON is an immunochromatographic test for quantitative determination of deoxynivalenol (DON) in grains. Objective: A study was conducted to validate performance of this method for determination of DON in naturally contaminated corn and wheat and in DON-spiked corn/soy blend, soybeans, barley, malted barley, buckwheat, brown rice, sorghum, and distillers dried grain. Methods: In addition to matrix testing, LOD, linearity, selectivity, robustness, and stability/lot-to-lot consistency testing were performed. Results: The LOD was determined to be 0.014 ppm in corn and 0.037 ppm in wheat, and the LOQ 0.042 ppm in corn and 0.11 ppm in wheat. Recovery ranged from 90 to 104% across a range of reference values of 0.5 to 34.5 ppm. Linearity calculation comparing test results with reference values produced R2 values of 0.999 in both matrixes. Internal results with corn and wheat were corroborated in independent laboratory testing. For DON-spiked commodities, mean recovery across a range of DON concentration from 0.5 to 30 ppm ranged from 90 to 109%. Results of selectivity testing showed no cross-reactivity with other mycotoxins and no interference in detection of DON. Reagent lot-to-lot consistency and stability studies showed consistent results across a range of DON levels and established expiration dating for the test of 18 months after manufacture when stored under specified conditions. Conclusions and Highlights: The Reveal Q+ for DON test offers reliable performance as well as the advantages of aqueous sample extraction, procedural simplicity, minimal labor and equipment requirements, and rapid results. Conclusions: The Reveal Q+ for DON test is validated as a Performace Tested Method in Corn, Wheat, and a variety of other grains. Highlights: The test provides rapid results from a simple aqueous extraction and requires minimal labor and equipment.

scholarly journals Fluorescence Polarization Immunoassay for the Determination of T-2 and HT-2 Toxins and Their Glucosides in Wheat

Toxins ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 380 ◽  
Author(s):  
Vincenzo Lippolis ◽  
Anna C. R. Porricelli ◽  
Erminia Mancini ◽  
Biancamaria Ciasca ◽  
Veronica M. T. Lattanzio ◽  
...  
Keyword(s):  
Fluorescence Polarization ◽  
Screening Method ◽  
High Sensitivity ◽  
Cross Reactivity ◽  
Screening Methods ◽  
The European Union ◽  
Fluorescence Polarization Immunoassay ◽  
Intermediate Precision ◽  
Relative Standard

T-2 and HT-2 toxins and their main modified forms (T-2 glucoside and HT-2 glucoside) may co-occur in cereals and cereal-based products. A fluorescence polarization immunoassay (FPIA) was developed for the simultaneous determination of T-2 toxin, HT-2 toxin and relevant glucosides, expressed as sum. The developed FPIA, using a HT-2-specific antibody, showed high sensitivity (IC50 = 2.0 ng/mL) and high cross-reactivity (100% for T-2 toxin and 80% for T-2 and HT-2 glucosides). The FPIA has been used to develop two rapid and easy-to-use methods using two different extraction protocols, based on the use of organic (methanol/water, 90:10, v/v) and non-organic (water) solvents, for the determination of these toxins in wheat. The two proposed methods showed analytical performances in terms of sensitivity (LOD 10 µg/kg) recovery (92–97%) and precision (relative standard deviations ≤13%), fulfilling the criteria for acceptability of an analytical method for the quantitative determination of T-2 and HT-2 toxins established by the European Union. Furthermore, the methods were then validated in accordance with the harmonized guidelines for the validation of screening methods included in the Regulation (EU) No. 519/2014. The satisfactory analytical performances, in terms of intermediate precision (≤25%), cut-off level (80 and 96 µg/kg for the two methods) and rate of false positives (<0.1%) confirmed the applicability of the proposed methods as screening method for assessing the content of these toxins in wheat at the EU indicative levels reported for T-2 and HT-2 toxins.

Turbidimetric Microbiological Determination of Oxytetracycline Hydrochloride in Finished Feeds and a Feed Premix: Collaborative Study

1980 ◽  
Vol 63 (5) ◽  
pp. 1038-1043
Author(s):  
Dorothy L Mueller-Brennecke ◽  
Shirley J Reed ◽  
Debra L Waisner ◽  
◽  
S Ahrens ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Collaborative Study ◽  
Plate Method ◽  
Relative Standard ◽  
Significant Difference ◽  
Aoac Method ◽  
Assay Methods ◽  
The Mean ◽  
Feed Premix

Abstract New automated and manual turbidimetric microbiological assay methods for oxytetracycline (OTC) in finished feeds and a feed premix were submitted to 17 collaborating laboratories for comparison with the official AOAC method. Six finished feeds of 50 and 100 g/ton levels and one premix containing 20 g OTC/lb were sent to the collaborators. Results were received from 12 laboratories. Six laboratories provided results derived from the Autoturb System and 7 laboratories performed the turbidimetric analyses manually. All 12 laboratories assayed the samples by the AOAC cylinder-plate method. Ranges of recoveries expressed as percent were 89.5–102.0, 91.2–97.0, and 91.4–96.0 for the AOAC, Autoturb turbidimetric, and manual turbidimetric methods, respectively. Average recoveries were 96.3, 93.4, and 93.6%, respectively. The mean relative standard deviation values were 5.7, 6.3, and 7.2, respectively. There was little significant difference between the turbidimetric methods and the AOAC method; however, the turbidimetric methods were faster.

Human Prothrombin Activation: Determination of Plasma and Serum Levels of Prothrombin Fragment 3 by Radioimmunoassay

1979 ◽  
Author(s):  
Daniel Walz ◽  
Thomas Brown
Keyword(s):  
Blood Clotting ◽  
Factor Xa ◽  
Heart Association ◽  
Serum Levels ◽  
Cross Reactivity ◽  
Assay Procedure ◽  
A Chain ◽  
Prothrombin Activation ◽  
Theoretical Amount

Human prothrombin activation is unique in that, in addition to the release of fragment 1.2 (FI.2) from the NH-terminus of prothrombin by factor Xa during the generation of thrombin, an additional 13 residue polypeptide, fragment 3 (F3), is autocatalytically removed from the amino-terminus of the thrombin A chain. We have developed a rapid radioimmunoassay for human F3 which incorporates short incubation times and the use of a preprecipitated second antibody; the assay can be performed in three hours. Specificity studies in buffer systems show prothrombin and prethrombin 1 cross-reacting at a level of 0.001; purified thrombin does not cross-react. In the presence of 5% BSA, prothrombin displays considerably less cross-reactivity. No immunoreactive material to F3 antibodies could be detected in 400 μL of plasma. Serum, obtained from whole blood clotting, contained measurable quantities of F3 (40-100 ng/mL). This amount in serum represents only 5-10% of the theoretical amount available should all of the fragment be hydrolytically cleaved during the conversion of prothrombin to thrombin. This assay procedure is currently being utilized to monitor the activation of purified human prothrombin in the absence and presence of selected plasma inhibitors. (Supported in part by NIH 05384-17 and the Michigan Heart Association).

An Automated Procedure for the Determination of Ammonia in Tobacco

1972 ◽  
Vol 6 (4) ◽  
Author(s):  
P.F. Collins ◽  
W.W. Lawrence ◽  
J.F. Williams
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Distillation Method ◽  
Relative Standard ◽  
Tobacco Sample ◽  
Automated Determination

AbstractA procedure for the automated determination of ammonia in tobacco has been developed. Ammonia is extracted from the ground tobacco sample with water and is determined with a Technicon Auto Analyser system which employs separation of the ammonia through volatilization followed by colourimetry using the phenate-hypochlorite reaction. The procedure has been applied to a variety of tobaccos containing from 0.02 to 0.5 % ammonia with an overall relative standard deviation of 2 %. The accuracy of the procedure as judged by recovery tests and by comparison to a manual distillation method is considered adequate

Atomic absorption determination of Hg (II), Cd (II), and As (III) in natural and waste water after preliminary group preconcentration

2019 ◽  
Vol 85 (2) ◽  
pp. 12-16
Author(s):  
I. V. Saunina ◽  
E. N. Gribanov ◽  
E. R. Oskotskaya
Keyword(s):  
Waste Water ◽  
Atomic Absorption ◽  
High Sensitivity ◽  
Distribution Coefficients ◽  
Neutral Medium ◽  
Atomic Absorption Determination ◽  
Absorption Determination ◽  
Relative Standard ◽  
Preliminary Group

The sorption of Hg (II), Cd (II), and As (III) by natural aluminosilicate is studied. It is shown that the mineral absorbs those toxicants in a rather wide pH range, quantitative extraction of analytes being achieved in a neutral or close to neutral medium (pH values range within 7.0 - 8.0; 6.3 - 7.5; 7.4 - 8.5 for Hg (II), As (III), and Cd (II), respectively). The effect of the time of phase contact on the degree of extraction of elements is shown. The sorption capacity of the mineral in optimal conditions of the medium acidity (0.06 mmol/g for mercury, 0.31 mmol/g for cadmium, and 0.52 mmol/g for arsenic) is determined. The distribution coefficients attain values of aboutnX 103-nX 104. A new combined method for determination of Hg (II), Cd (II), and As (III) in natural and waste water is developed and tested. The method consists in a preliminary group sorption concentration of the analytes by aluminosilicate, desorption of the analytes from the surface of the mineral and their subsequent atomic absorption determination. The correctness of the method is verified in analysis of spiked samples. The method is easy to use and exhibits high sensitivity, reproducibility and accuracy of analyte determination. The relative standard deviation does not exceed 0.13. Economic availability and possibility of using domestic sorption materials are the important advantages of the proposed procedure which can be used in the practice of laboratories monitoring the quality and safety of environmental objects.

Stability Indicating Liquid Chromatographic Method for the Determination of Fenofibrate and its Application to Kinetic Studies

2013 ◽  
Vol 5 (4) ◽  
pp. 1866-1874
Author(s):  
K. Srinivasa Rao ◽  
Keshar N K ◽  
N Jena ◽  
M.E.B Rao ◽  
A K Patnaik
Keyword(s):  
Degradation Products ◽  
Kinetic Studies ◽  
Pharmaceutical Formulations ◽  
Assay Method ◽  
Pharmaceutical Dosage Form ◽  
Stability Indicating ◽  
Zero Order Kinetics ◽  
Relative Standard ◽  
Liquid Chromatographic

A stability-indicating LC assay method was developed for the quantitative determination of fenofibrate (FFB) in pharmaceutical dosage form in the presence of its degradation products and kinetic determinations were evaluated in acidic, alkaline and peroxide degradation conditions. Chromatographic separation was achieved by use of Zorbax C18 column (250 × 4.0 mm, 5 μm). The mobile phase was established by mixing phosphate buffer (pH adjusted 3 with phosphoric acid) and acetonitrile (30:70 v/v). FFB degraded in acidic, alkaline and hydrogen peroxide conditions, while it was more stable in thermal and photolytic conditions. The described method was linear over a range of 1.0-500 μg/ml for determination of FFB (r= 0.9999). The precision was demonstrated by relative standard deviation (RSD) of intra-day (RSD= 0.56– 0.91) and inter-day studies (RSD= 1.47). The mean recovery was found to be 100.01%. The acid and alkaline degradations of FFB in 1M HCl and 1M NaOH solutions showed an apparent zero-order kinetics with rate constants 0.0736 and 0.0698  min−1 respectively and the peroxide degradation with 5% H2O2 demonstrated an apparent first-order kinetics with rate constant k = 0.0202 per min. The t1/2, t90   values are also determined for all the kinetic studies. The developed method was found to be simple, specific, robust, linear, precise, and accurate for the determination of FFB in pharmaceutical formulations.  

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