scholarly journals The Determination of Six Ionophore Coccidiostats in Feed by Liquid Chromatography with Postcolumn Derivatisation and Spectrofotometric/Fluorescence Detection

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Małgorzata Olejnik ◽  
Piotr Jedziniak ◽  
Teresa Szprengier-Juszkiewicz
Keyword(s):  
Drug Resistance ◽  
Liquid Chromatography ◽  
Fluorescence Detection ◽  
Internal Standard ◽  
Reversed Phase ◽  
Feed Additives ◽  
Core Shell ◽  
Proficiency Tests ◽  
Reversed Phase Hplc

The control of levels of anticoccidial feed additives in targeted feeds plays an important role in the assurance of efficiency of animal treatment, prevention of drug resistance, and food safety. The robust and labour-efficient method for the simultaneous determination of six ionophore coccidiostats (lasalocid, maduramicin, monensin, narasin, salinomycin, and semduramicin) in targeted feed has been developed. Properly grinded and homogenized feed sample was spiked with internal standard (monesin methyl ester) and extracted with methanol. The extract was analysed with reversed phase HPLC without any further purification. The separation of the analytes with conventional C18 and core-shell columns was compared. Lasalocid was analysed with fluorescence detection, whereas other ionophores were detected with UV-Vis detector after derivatisation with vanillin in the presence of sulfuric acid. Fortified samples and targeted feeds at authorized levels were used for method validation. Recovery was in the range of 85–110%, depending on the analyte. The within-laboratory reproducibility did not exceed the target value from Horwitz equation. The results of the proficiency tests (z-scores in the range of −1.0 to 1.9) confirmed the reliability of the developed protocol.

Sensitive Determination of Zearalenone and α-Zearalenol in Barley and Job's-Tears by Liquid Chromatography with Fluorescence Detection

1993 ◽  
Vol 76 (5) ◽  
pp. 1006-1009 ◽  
Author(s):  
Touicm Tanaka ◽  
Reiko Teshima ◽  
Hideharu Ikebuchi ◽  
Jun-Ichi Sawada ◽  
Tadao Terao ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Detection Limit ◽  
Fluorescence Detection ◽  
Reliable Method ◽  
Internal Standard ◽  
Reversed Phase ◽  
Job’S Tears ◽  
Sensitive Determination ◽  
Liquid Chromatographic

Abstract A sensitive and reliable method for liquid chromatographic (LC) determination of zearalenone and α-azearalenol in barley and Job's-tears was investigated. The method by which these toxins were determined involves addition of an internal standard (zearalenone 6'-oxime) to barley and Job's-tears samples. Extracts from grain samples were cleaned up by passage through chromatography on piperidinohydroxypropyl Sephadex LH-20 as a lipophilic gel. Individual toxins were resolved by LC on a reversed-phase (ODS) column with fluorescence detection. The detection limit is estimated to be 0.2 ng for zearalenone and α-zearalenol standards. Known amounts of zearalenone and α-azearalenol (25-1250 ng) were added to a barley sample (5 g). Average recoveries for α-zearalenol and zearalenone, respectively, ranged from 96 to 102% (mean CV, 3.6%) and from 96 to 103% (mean CV, 3.3%). This method is applicable to determination of α-zearalenol and zearalenone in barley and Job's-tears with satisfactory sensitivity and accuracy.

Determination of urinary normetanephrine and metanephrine by radial-compression liquid chromatography and electrochemical detection.

1983 ◽  
Vol 29 (2) ◽  
pp. 305-309 ◽  
Author(s):  
P J Orsulak ◽  
P Kizuka ◽  
E Grab ◽  
J J Schildkraut
Keyword(s):  
Liquid Chromatography ◽  
Electrochemical Detection ◽  
Depressive Disorders ◽  
Internal Standard ◽  
Normal Subjects ◽  
Reversed Phase ◽  
Radial Compression ◽  
Ion Pair Chromatography ◽  
Catecholamine Metabolites

Abstract A procedure has been developed for determining the O-methylated catecholamine metabolites, normetanephrine and metanephrine, in urine by use of radial-compression liquid chromatography followed by electrochemical detection. Normetanephrine and metanephrine are isolated from hydrolyzed urine by ion-exchange on small, commercially available, disposable columns and preconcentrated by solvent extraction. They are then separated by reversed-phase ion-pair chromatography, with use of a radial compression cartridge and radial compression module, and quantified with 3-methoxy-4-hydroxybenzylamine as internal standard. Normetanephrine, metanephrine, and the internal standard are separated from interfering peaks in about 15 min. The method is applicable to the relatively low amounts of normetanephrine (100-600 micrograms/24 h) and metanephrine (50-400 micrograms/24 h) found in normal subjects and patients with depressive disorders or hypertension. Within-day CVs ranged from 1.1 to 2.2% for normetanephrine and 1.2 to 6.9% for metanephrine; the corresponding between-day CVs were 4.9 and 5.7% over these ranges.

Determination of Polynuclear Aromatic Hydrocarbons in Seafood by Liquid Chromatography with Fluorescence Detection

1992 ◽  
Vol 75 (5) ◽  
pp. 872-877 ◽  
Author(s):  
Gracia A Perfetti ◽  
Patricia J Nyman ◽  
Sheryl Fisher ◽  
Frank L Joe ◽  
Gregory W Diachenko
Keyword(s):  
Liquid Chromatography ◽  
Fluorescence Detection ◽  
Aromatic Hydrocarbons ◽  
Solid Phase ◽  
Reversed Phase ◽  
Polynuclear Aromatic Hydrocarbons ◽  
Matrix Interferences ◽  
Phase Liquid ◽  
Certified Values

Abstract Modification of a previously published method for determination of polynuclear aromatic hydrocarbons (PAHs) produces very clean seafood extracts in less than half the time. After alkaline digestion of the seafood, PAHs were partitioned into 1,1,2- trichlorotrifluoroethane. The resulting extract was cleaned up by solid-phase extraction on alumina, silica, and C18 adsorbents and then analyzed by gradient reversed-phase liquid chromatography with programmable fluorescence detection. Average recoveries of 12 PAHs [acenaphthene, anthracene, fluoranthene, pyrene, benz(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)- fluoranthene, benzo(a)pyrene, dibenz(a,h)anthracene, benzo(ghi)perylene, and indeno(1,2,3-cd)pyrene] from 5 different matrixes (mussels, oysters, clams, crabmeat, and salmon) spiked at low partsper- billion levels ranged from 76 to 94%. Estimated limits of quantitation ranged from 0.01 to 0.6 ppb PAHs in extracts that were free of matrix interferences. Results of analyses of a mussels standard reference material obtained from the National Institute of Standards and Technology were in good agreement with the certified values.

scholarly journals Determination of Sulfonamides in Edible Salmon Tissue by Liquid Chromatography with Postcolumn Derivatization and Fluorescence Detection

1997 ◽  
Vol 80 (4) ◽  
pp. 751-755 ◽  
Author(s):  
Theresa A Gehring ◽  
Larry G Rushing ◽  
Harold C Thompson
Keyword(s):  
Acetic Acid ◽  
Liquid Chromatography ◽  
Fluorescence Detection ◽  
Coho Salmon ◽  
Gradient Elution ◽  
Reversed Phase ◽  
Aqueous Acetic Acid ◽  
Postcolumn Derivatization

Abstract Fourteen sulfonamides—sulfanilamide, sulfadiazine, sulfathiazole, sulfapyridine, sulfam- erazine, sulfamethazine, sulfamethizole, sulfamethoxypyridazine, sulfachloropyridazine, sulfamonomethoxine, suļfadoxine, sulfamethoxazole, sulfadimethoxine, and sulfaquinoxoline—residues of which could be found in aquacultured species, were separated in <25 min by reversed-phase (C18) liquid chromatography (LC) with gradient elution. Analytes were extracted from edible salmon tissue (muscle and adhering skin) with acetonitrile—2% aqueous acetic acid, isolated with 2 liquid-liquid partitionings, and derivatized with fluorescamine after eluting from the column. The derivatives were detected by fluorescence. Recoveries (n = 4) from coho salmon fortified with sulfonamides at 5,10, and 20 ng/g tissue averaged 79.7± 7.3, 84.6 ± 7.7, and 88.2 ± 7.1%, respectively. Limits of quantitation were 5 ng/g tissue, for sulfanilamide, sulfamethoxypyridazine, and sulfaquinoxoline and 1 ng/g tissue for the remaining sulfonamides.

scholarly journals Multiresidue Determination of Fluoroquinolones in Eggs

2000 ◽  
Vol 83 (6) ◽  
pp. 1306-1312 ◽  
Author(s):  
Marilyn J Schneider ◽  
Dan J Donoghue
Keyword(s):  
Liquid Chromatography ◽  
Fluorescence Detection ◽  
Small Volume ◽  
Reversed Phase ◽  
Reversed Phase Liquid Chromatography ◽  
Trace Enrichment ◽  
On Line ◽  
Phase Liquid ◽  
Multiresidue Determination

Abstract A multiresidue method was developed for the determination of fluoroquinolones in eggs. Extraction of eggs with ammoniacal acetonitrile was followed by liquid–liquid defatting, solvent evaporation, and redissolution in a small volume of buffer. The fluoroquinolones were further purified by on-line microdialysis, concentrated on a trace enrichment column, and separated by reversed-phase liquid chromatography with fluorescence detection. Norfloxacin (NOR), ciprofloxacin (CIP), and sarafloxacin (SAR) were extracted from fortified eggs over a range of 2–200 μg/kg, with recoveries of 65.7–78.9%, 65.6–77.1%, and 67.6–110%, respectively. Enrofloxacin (ENRO) was extracted over a range of 1–100 μg/kg, with recoveries of 71.5–86.7%, whereas desethylene ciprofloxacin (DCIP) and danofloxacin (DANO) were extracted over a range of 0.2–20 μg/kg, with recoveries of 68.7–90.7% and 76.0–93.8%, respectively. The limits of quantitation for the 6 fluoroquinolones were as follows: DCIP and DANO, 0.3 μg/kg; ENRO, 1 μg/kg; NOR and CIP, 2 μg/kg; and SAR, 3 μg/kg. Both SAR and ENRO incurred eggs were also successfully analyzed using this method.

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