scholarly journals Biosensor Immunoassay of Ivermectin in Bovine Milk

2002 ◽  
Vol 85 (4) ◽  
pp. 879-882 ◽  
Author(s):  
Jeanne V Samsonova ◽  
G Andrew Baxter ◽  
Steven R H Crooks ◽  
Christopher T Elliott
Keyword(s):  
Solid Phase ◽  
Bovine Milk ◽  
Optical Biosensor ◽  
Considerable Change ◽  
Extraction Techniques ◽  
Milk Samples ◽  
Assay Procedure ◽  
Working Day ◽  
Milk Storage

Abstract A rapid and sensitive biosensor immunoassay was developed for determination of ivermectin residues in bovine milk. A detection limit of 16.2 ng/mL was achieved. A Biacore optical biosensor based on surface plasmon resonance was used, and a range of extraction techniques was investigated. In the final assay procedure, ivermectin was extracted with acetonitrile followed by C8 solid-phase extraction cleanup. It was proven experimentally that 2 methods of milk storage, freezing or addition of mercury-containing compounds as preservatives, could be used without considerable change in detected concentrations (samples were fortified with ivermectin after storage). The average values for milk samples spiked at 100 and 50 ng/mL concentrations were 102.6 and 51.5 ng/mL, respectively. Extraction and analysis of 20 milk samples were performed within a single working day.

A Novel Solid-phase Microextraction Method Coupled with HPLC for Determination of Four Sulfonamides in Milk Samples

2013 ◽  
Vol 41 (4) ◽  
pp. 529
Author(s):  
Ying PENG ◽  
Huan HE ◽  
Cheng SUN ◽  
Ya-Ling ZHANG ◽  
Wen-Chao LI ◽  
...  
Keyword(s):  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Milk Samples

Fluorometric determination of uric acid in bovine milk

2010 ◽  
Vol 77 (4) ◽  
pp. 438-444 ◽  
Author(s):  
Torben Larsen ◽  
Kasey M Moyes
Keyword(s):  
Heat Treatment ◽  
Uric Acid ◽  
Xanthine Oxidase ◽  
Bovine Milk ◽  
Oxidase Inhibitor ◽  
Enzymatic Oxidation ◽  
Fast Method ◽  
Xanthine Oxidase Inhibitor ◽  
Milk Samples

The primary objective of this study is to validate a new fast method for determination of uric acid in milk. The method is based on an enzymatic-fluorometric technique that requires minimal pre-treatment of milk samples. The present determination of uric acid is based on the enzymatic oxidation of uric acid to 5-hydroxyisourate via uricase where the liberated hydrogen peroxide reacts with 10-acetyl-3,7-dihydroxyphenoxazine via peroxidase and the fluorescent product, resorufin, is measured fluorometrically. Fresh composite milk samples (n=1,072) were collected from both Jersey (n=38) and Danish Holstein (n=106) cows from one local herd. The average inter- and intra-assay variations were 7·1% and 3·0%, respectively. Percent recovery averaged 103·4, 107·0 and 107·5% for samples spiked with 20, 40 or 60 μmof standard, respectively, with a correlation (r=0·98;P<0·001) observed between the observed and expected uric acid concentrations. A positive correlation (r=0·96;P<0·001) was observed between uric acid concentrations using the present method and a reference assay. Storage at 4°C for 24 h resulted in lower (P<0·01) uric acid concentrations in milk when compared with no storage or samples stored at −18°C for 24 h. Addition of either allopurinol (a xanthine oxidase inhibitor) or dimethylsulfoxide (a solvent for allopurinol) did not affect milk uric acid concentrations (P=0·96) and may indicate that heat treatment before storage and analysis was sufficient to degrade xanthine oxidase activity in milk. No relationship was observed between milk uric acid and milk yield and milk components. Authors recommend a single heat treatment (82°C for 10 min) followed by either an immediate analysis of fresh milk samples or storage at −18°C until further analysis.

scholarly journals Dispersive solid-phase extraction based on butylamide silica for the determination of sulfamethoxazole in milk samples by capillary electrophoresis

2016 ◽  
Vol 39 (14) ◽  
pp. 658-665 ◽  
Author(s):  
Gabriela Islas ◽  
José A. Rodríguez ◽  
M. Elena Páez-Hernández ◽  
Silvia Corona-Avendaño ◽  
Alberto Rojas-Hernández ◽  
...  
Keyword(s):  
Capillary Electrophoresis ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Phase Extraction ◽  
Dispersive Solid Phase Extraction ◽  
Milk Samples

scholarly journals Magnetic Solid-Phase Extraction using Ionic Liquid-Modified Magnetic Nanoparticles for The Simultaneous Extraction of Cadmium and Lead in Milk Samples; Evaluation of Measurement Uncertainty

2021 ◽  
Vol 65 (4) ◽  
Author(s):  
Sara Khodadadi ◽  
Elaheh Konoz ◽  
Ali Ezabadi ◽  
Ali Niazi
Keyword(s):  
Ionic Liquid ◽  
Magnetic Nanoparticles ◽  
Solid Phase ◽  
Magnetic Solid Phase Extraction ◽  
Phase Extraction ◽  
Simultaneous Extraction ◽  
Milk Samples ◽  
Magnetic Solid ◽  
Modified Magnetic Nanoparticles

Abstract. In the present study, a new, sensitive, and rapid method was developed for extraction and determination of the trace amounts of Pb (II) and Cd (II) ions in milk samples through magnetic solid-phase extraction using DABCO based-ionic liquid-modified magnetic nanoparticles (Fe3O4/[DABCO-PDO]Cl NPs). Herein, Pb (II) and Cd (II) contents were quantified with flame atomic absorption spectroscopy (FAAS). The effect of different empirical parameters (such as sample pH, adsorbent amount, type and amount of the elution, extraction and desorption times, and the ligand concentration) was evaluated and optimized for simultaneous extraction and pre-concentration Pb (II) and Cd (II) ions. The calibration curve was linear under the optimum condition in the concentration range of 0.4-200 µgL-1 for Cd, and 0.5-120 µgL-1 for Pb, respectively. The pre-concentration factor was 67, with the detection limit of 0.09 and 0.07 µgL-1 for Pb and Cd, respectively. The relative standard deviation values (RSD %) of the proposed method were lower than 2.6 %. The developed method was successfully used to determine lead and cadmium content in milk samples. The information obtained from the method validation has been used to estimate the expanded uncertainty for the determination of Pb (II) and Cd (II) at trace levels in commercial milks.   Resumen. En este trabajo, se ha desarrollado un nuevo, sensible y rápido procedimiento para la extracción y determinación de iones Pb(II) y Cd(II) a nivel de trazas en leche, mediante extracción en fase sólida utilizando nanopartículas magnéticas modificadas con líquido iónico basado en DABCO (Fe3O4/[DABCO-PDO]Cl NPs). La determinación de ambos metales se llevó a cabo por espectrometría de absorción atómica con atomización en llama. Se ha evaluado el efecto de diferentes parámetros empíricos (tales como pH, cantidad de adsorbente, tipo y cantidad de solvente de elución, tiempo de extracción y desorción, y concentración del ligando); estos parametros fueron optimizados enfocándose en la extracción y preconcentración simultanea de ambos iones. Empleando las condiciones establecidas, se obtuvo buena linealidad de las curvas de calibración en el intervalo de concentraciones 0.4-200 µgL-1 para Cd, y 0.5-120 µgL-1 para Pb, respectivamente. Se logró el factor de preconcentración 67, con los límites de detección 0.09 y 0.07 µgL-1 para Pb y Cd, respectivamente. Los valores de desviación estandar relativa (RSD %) en el procedimiento propuesto no sobrepasaron 2.6 %. En el análisis de leche, se obtuvieron resultados satisfactorios. Los datos obtenidos en etapa de validación se utilizaron para estimar la incertidumbre expandida en la determinación de Pb y Cd a nivel de trazas en leche.

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