Development of a Flow-Through Enzyme Immunoassay and Application in Screening Green Coffee Samples for Ochratoxin A with Confirmation by High-Performance Liquid Chromatography

2001 ◽  
Vol 64 (10) ◽  
pp. 1597-1602 ◽  
Author(s):  
L. SIBANDA ◽  
S. DE SAEGER ◽  
T. G. M. BAUTERS ◽  
H. J. NELIS ◽  
C. VAN PETEGHEM
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Enzyme Immunoassay ◽  
Ochratoxin A ◽  
High Performance ◽  
Hplc Method ◽  
Coffee Bean ◽  
Green Coffee ◽  
Penicillium Species ◽  
Flow Through

A flow-through enzyme immunoassay has been developed for the screening of green coffee bean samples for ochratoxin A (OA) and was later used in a survey on OA in green coffee from different countries. The test has a sensitivity of 8 ng/g, and calculated recoveries ranged from 70 to 89% and from 86 to 95% for spiked and naturally contaminated samples, respectively. There were no significant differences in within-day and between-day assay performance (P > 0.05). Green coffee samples (15 Arabica and 7 Robusta) received from an international coffee trader were analyzed for intrinsic fungal contamination, screened for OA, and subsequently confirmed by high-performance liquid chromatography (HPLC). All 22 samples were contaminated by fungal species of the genus Aspergillus, while Penicillium species were isolated from a mere 13.6% of the total number of samples. Isolates were tested for their ability to produce OA, and only 3.9% were positive. There was no correlation between occurrence of OA-producing isolates and levels of OA in contaminated samples. Results of the screening procedure showed that 4 of the 22 samples were contaminated with 8 ng/g or higher. The HPLC method confirmed that the OA levels ranged from 27 to 168 ng/g. A fifth sample, which was shown to be negative during screening, had an OA concentration of 4 ng/g. There were no false negatives or positives recorded, and the flow-through enzyme immunoassay results correlated with those obtained by HPLC.

Ochratoxins A and B, Xanthomegnin, Viomellein and Vioxanthin Production by Isolates of Aspergillus ochraceus from Green Coffee Beans

1983 ◽  
Vol 46 (11) ◽  
pp. 965-968 ◽  
Author(s):  
MICHAEL E. STACK ◽  
PHILIP B. MISLIVEC ◽  
TURGUT DENIZEL ◽  
REGINA GIBSON ◽  
ALBERT E. POHLAND
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Ochratoxin A ◽  
High Performance ◽  
Toxin Production ◽  
Aspergillus Ochraceus ◽  
Average Level ◽  
Green Coffee ◽  
Green Coffee Beans ◽  
Coffee Beans

Isolates from Aspergillus ochraceus obtained from green coffee beans were cultured on rice and water. After 20 d of growth the cultures were extracted with chloroform and the extracts were analyzed by high performance liquid chromatography for ochratoxin A (OA), ochratoxin B (OB), xanthomegnin (X), viomellein (V) and vioxanthin (VX). Forty-three percent of the isolates produced OA at an average level of 397 μg of toxin/g rice, 17% produced OB at an average level of 312 μg/g, and 84% produced X, V, and VX at an average level of 281, 417 and 386 μg/g, respectively. The highest levels of toxin production were OA, 2088 μg/g; OB, 3375 μg/g; X, 1562 μg/g; V, 2514 μg/g; and VX, 2054 μg/g. VX has not previously been reported as an A. ochraceus metabolite.

scholarly journals Evaluation of the Abbott IMxTM fluorescence polarization immunoassay and the Bio-Rad enzyme immunoassay for homocysteine: comparison with high-performance liquid chromatography

2000 ◽  
Vol 37 (2) ◽  
pp. 194-198 ◽  
Author(s):  
James G Donnelly ◽  
Claire Pronovost
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Enzyme Immunoassay ◽  
Fluorescence Polarization ◽  
High Performance ◽  
Hplc Method ◽  
Adenosylhomocysteine Hydrolase ◽  
Technological Advantage ◽  
Analytical Step ◽  
Peroxidase Conjugate

We evaluated the precision, linearity and accuracy of the Abbott IMxTM and Bio-Rad (Axis) homocysteine assays. Both assays make use of S-adenosylhomocysteine hydrolase and excess adenosine, to convert homocysteine to S-adenosylhomocysteine (SAH). A monoclonal anti-SAH antibody is then used to quantify SAH. The IMx assay measures the fluorescence polarization of a conjugated SAH analogue for the final analytical step, whereas the Bio-Rad method uses a microplate enzyme immunoassay (EIA) employing an anti-mouse antibody-peroxidase conjugate. The Abbott procedure is completely automated whereas the Bio-Rad EIA is performed manually. Between-run coefficient of variation using commercial controls was 2·6% at 7 μmol/L, 2·5% at 13 μmol/L and 1·7% at 24 μmol/L for the Abbott method, and 19·7% at 6·4 μmol/L, 15·9% at 11·0 μmol/L and 14·5% at 23·4 μmol/L for the Bio-Rad method. Both assays correlated well with a high-performance liquid chromatography (HPLC) procedure for homocysteine: Bio-Rad EIA=1·03HPLC + 1·0 μmol/L, r=0·98, sy/x=0·51; Abbott IMx=1·02 HPLC + 0·7 μmol/L, r=0·99, sy/x=0·33. Both methods were linear up to 50 mol/L homocysteine. The IMx assay had superior precision as well as the technological advantage of being completely automated. Both immunoassays exhibited greatly improved throughput compared with our existing HPLC method.

Developing a High-performance Liquid Chromatography Method for Simultaneous Determination of Loratadine and its Metabolite Desloratadine in Human Plasma

2020 ◽  
Vol 20 (13) ◽  
pp. 1053-1059
Author(s):  
Mahmoud M. Sebaiy ◽  
Noha I. Ziedan
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Human Plasma ◽  
High Performance ◽  
Allergic Diseases ◽  
Reversed Phase ◽  
Hplc Method ◽  
H1 Receptor ◽  
Chromatography Method

Background: Allergic diseases are considered as the major burden on public health with increased prevalence globally. Histamine H1-receptor antagonists are the foremost commonly used drugs in the treatment of allergic disorders. The target drug in this study, loratadine, belongs to this class of drugs and its biometabolite desloratadine which is also a non-sedating H1 receptor antagonist with anti-histaminic activity being 2.5 to 4 times greater than loratadine. This study aimed to develop and validate a novel isocratic Reversed-phase High-Performance Liquid Chromatography (RP-HPLC) method for rapid and simultaneous separation and determination of loratadine and its metabolite, desloratadine in human plasma. Methods: The drug extraction method from plasma was based on protein precipitation technique. The separation was carried out on a Thermo Scientific BDS Hypersil C18 column (5μm, 250 x 4.60 mm) in a mobile phase of MeOH: 0.025M KH2PO4 adjusted to pH 3.50 using orthophosphoric acid (85: 15, v/v) at an ambient temperature. The flow rate was maintained at 1 mL/min and maximum absorption was measured using the PDA detector at 248 nm. Results: The retention times of loratadine and desloratadine in plasma samples were recorded to be 4.10 and 5.08 minutes, respectively, indicating a short analysis time. Limits of detection were found to be 1.80 and 1.97 ng/mL for loratadine and desloratadine, respectively, showing a high degree of sensitivity of the method. The method was then validated according to FDA guidelines for the determination of the two analytes in human plasma. Conclusion: The results obtained indicate that the proposed method is rapid, sensitive in the nanogram range, accurate, selective, robust and reproducible compared to other reported methods.

HPLC Analysis of Oxytetracycline Residues in Honey

1986 ◽  
Vol 49 (5) ◽  
pp. 383-388 ◽  
Author(s):  
PETER SPORNS ◽  
SUET KWAN ◽  
LAWRENCE A. ROTH
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Aqueous Solutions ◽  
High Performance ◽  
Hplc Analysis ◽  
Extraction Procedure ◽  
Hplc Method ◽  
Limits Of Detection ◽  
Ph Values ◽  
Double Extraction

Oxytetracycline (OTC), also known commercially as Terramycin, was determined to be more stable in honey than in buffered aqueous solutions at similar pH values and temperatures. A rapid high performance liquid chromatography (HPLC) method was developed to detect and quantitate OTC using a 1:1 dilution (wt/wt) of honey samples in water. Using 355 nm as the wavelength of detection, amounts as low as 0.5 μg/ml could be detected in the above solution. The limits of detection were lowered considerably by a double extraction procedure.

scholarly journals A Selective High-Performance Liquid Chromatography Method for the Determination of Reboxetine in Bulk Drug and Tablets

2006 ◽  
Vol 89 (6) ◽  
pp. 1552-1556
Author(s):  
ArmaĞan Önal ◽  
Olcay SaĞiri ◽  
S Müge Çetin ◽  
Sidika Toker
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Depressive Disorders ◽  
Degradation Products ◽  
Severe Depression ◽  
Hplc Method ◽  
Chromatography Method ◽  
Relative Standard

Abstract Reboxetine is used as a selective noradrenaline reuptake inhibitor for the treatment of major depressive disorders. It is effective in the treatment of severe depression and safer to use than traditional tricyclic antidepressants. In this study, a novel, simple, and rapid stability-indicating high-performance liquid chromatography (HPLC) method for reboxetine methansulfonate was successfully developed and validated for the assay of tablets. The method was used to quantify reboxetine in tablets; it employed a C18 column (150 4.6 mm id) with an isocratic mobile phase consisting of methanolphosphate buffer (pH 7, 0.02 M; 55 + 45, v/v) at a flow rate of 1.0 μmL/min. Reboxetine was detected by an ultraviolet detector at 277 nm. The retention time of reboxetine was about 4.5 min. The developed HPLC method was validated with respect to linearity, precision, sensitivity, accuracy, and selectivity. The method was linear over the concentration range 150 g/mL (r 0.9999). The limits of detection and the quantitation of reboxetine were 0.1 and 0.3 μg/mL, respectively. The relative standard deviation values for intraday and interday precision were 0.781.01 and 1.081.37%, respectively. Selectivity was validated by subjecting a stock solution of reboxetine to neutral, acid, and alkali hydrolysis, as well as oxidation, dry heat treatment, and photodegradation. The peaks of the degradation products did not interfere with the peak of reboxetine. The results indicated that the proposed method could be used in a stability assay. The proposed method was successfully applied to the determination of reboxetine in tablets. Excipients present in the tablets did not interfere with the analysis.

Development of reverse phase-high performance liquid chromatography (RP-HPLC) method for determination of selected antihypertensive active flavonoids (rutin, myricetin, quercetin, and kaempferol) in medicinal plants found in Botswana

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Katso Binang ◽  
David T. Takuwa
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Medicinal Plants ◽  
High Performance ◽  
Zingiber Officinale ◽  
Hplc Method ◽  
Reverse Phase ◽  
Rp Hplc ◽  
Lippia Javanica

Abstract The aim of the study was to develop a rapid, efficient, and cheap chromatographic method for determining four selected antihypertensive active flavonoid compounds in medicinal plants in Botswana. The determination of rutin, quercetin, and kaempferol in selected medicinal plants was conducted in less than 6 min using the developed reverse phase-high performance liquid chromatography (RP-HPLC) method with a 2.7 µm Ascentis C18 express column (150 × 4.60 mm i.d) at 340, 360, and 368 nm detection wavelengths and mobile phase of methanol and 0.068% of formic acid solution in isocratic elution. Validation results showed good selectivity, linearity (r 2 > 0.99), high percentage recoveries (90.2–104.7%), and precision (% RSD < 2) for n = 3, confirming suitability of the method for determination of the investigated flavonoids in Zingiber officinale (ginger). Application of the developed RP-HPLC method was performed in selected medicinal plants (Lippia javanica ) (mosukujane), Myrothanmus flabellious (galalatshwene), and Elephantorrhiza elephantina (mositsana) used to manage hypertension by herbalists in Botswana. M. flabellious a very commonly used plant for managing hypertension was found to contain highest amounts of rutin and myricetin, whereas nothing was detected for E. elephantina.

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