Determination of Narasin in Raw Material, Premix, and Animal Feeds by Liquid Chromatography and Correlation to Microbiological Assay

1994 ◽  
Vol 77 (4) ◽  
pp. 821-828 ◽  
Author(s):  
John M Rodewald ◽  
John W Moran ◽  
Alwin L Donoho ◽  
Mark R Coleman
Keyword(s):  
Liquid Chromatography ◽  
Chemical Composition ◽  
Microbiological Assay ◽  
Raw Material ◽  
Reference Standard ◽  
Wavelength Detector ◽  
Acidic Conditions ◽  
The Individual ◽  
Postcolumn Derivatization

Abstract A method is described for the detection and quantitation of narasin in raw material, premix, and feeds by liquid chromatography (LC) and postcolumn derivatization (PCD) with vanillin. Narasin was mixed with vanillin under acidic conditions and heated, and the resulting products were measured by a variable-wavelength detector operating at 520 nm. The LC responses of narasin and narasinlike factors were determined and correlated to the microbiological response of each factor as determined with Streptococcus faecium. Narasin reference standard was characterized in the same manner as the individual factors. The chemical composition of the reference standard (i.e., the amounts of narasin factors expressed in percent) combined with the relative microbiological potency value was used to calculate the biopotency contribution of each narasin factor. A formula was used to transform chemical composition values (amounts of narasin factors expressed in percent) of the reference standard to total microbiological activity as directly obtained from the microbiological assay. The LC method was validated by analyses of raw material, premix, and cattle and poultry rations.

Determination of Monensin in Raw Material, Premix, and Animal Feeds by Liquid Chromatography with Correlation to Microbiological Assay

1992 ◽  
Vol 75 (2) ◽  
pp. 272-279 ◽  
Author(s):  
J Matthew Rodewald ◽  
John W Moran ◽  
Alvin L Donoho ◽  
Mark R Coleman
Keyword(s):  
Liquid Chromatography ◽  
Chemical Composition ◽  
Microbiological Assay ◽  
Raw Material ◽  
Individual Factors ◽  
Reference Standard ◽  
Microbiological Activity ◽  
Acidic Conditions ◽  
The Individual

Abstract A method Is described for the detection and quantitation of monensin In raw material, premix, and feeds by liquid chromatography (LC) with postcolumn derlvatlzatlon with vanillin. Monensin was mixed with vanillin under acidic conditions and heated, and the resulting products were measured by a variable wavelength visible detector operating at 520 nm. The LC response of monensin and monensln-llke factors was determined and correlated to the microbiological response of each factor as determined with Streptococcus faeclum. Monensin reference standard was characterized In the same manner as the individual factors. The chemical composition of the reference standard and the relative microbiological potency values were used In combination to calculate the biopotency contribution of each of the monensin factors. A formula was used to transform chemical composition values of the reference standard to total microbiological activity as obtained directly from a microbiological assay. The formula was tested by comparing samples assayed by LC using the formula to report microbiological potency with samples assayed by the Autoturb method. Finally, the LC method was validated with raw material, premix, cattle rations (including liquid supplements), and poultry rations.

Determination of Monensin in Chicken Tissues by Liquid Chromatography with Postcolumn Derivatization

1994 ◽  
Vol 77 (4) ◽  
pp. 885-890 ◽  
Author(s):  
John W Moran ◽  
J Matthew Rodewald ◽  
Alvin L Donoho ◽  
Mark R Coleman
Keyword(s):  
Liquid Chromatography ◽  
Silica Gel ◽  
Chicken Tissues ◽  
Chicken Muscle ◽  
Limit Of Quantitation ◽  
Microbiological Techniques ◽  
Wavelength Detector ◽  
Acidic Conditions ◽  
Postcolumn Derivatization

Abstract A method is described for the detection and quantitation of monensin in chicken tissues by liquid chromatography with postcolumn derivatization with vanillin. Monensin is extracted from the tissues by homogenization with methanol–water and is isolated and concentrated by liquid–liquid partition and sorbent extraction with silica gel. Monensin is mixed postcolumn with vanillin under acidic conditions and heated, and the resulting products are measured by a variable-wavelength detector operating at 520 nm. The method has a limit of quantitation of 0.025 μg/g and is validated for use in the analyses of chicken muscle, liver, and skin (with adhering fat tissues) for monensin. Standard recoveries from the 3 tissue types tested at 3 levels ranged from 82 to 96%. The method represents an improvement in specificity, accuracy, and analysis time over existing methods, which use microbiological techniques.

Determination of Monensin in Edible Bovine Tissues and Milk by Liquid Chromatography

1995 ◽  
Vol 78 (3) ◽  
pp. 668-673 ◽  
Author(s):  
John W Moran ◽  
James M Turner ◽  
Mark R Coleman
Keyword(s):  
Liquid Chromatography ◽  
Silica Gel ◽  
Analysis Time ◽  
Bovine Muscle ◽  
Limit Of Quantitation ◽  
Wavelength Detector ◽  
Acidic Conditions ◽  
Postcolumn Derivatization

Abstract A method is described for detection and quantitation of monensin in bovine tissues by liquid chromatography (LC) with postcolumn derivatization (PCD) with vanillin. Monensin is extracted from the tissues by homogenization with methanol–water and is isolated and concentrated by liquid–liquid partition and sorbent extraction with silica gel. Monensin is mixed postcolumn with vanillin under acidic conditions and heated, and the resulting products are measured by a variable-wavelength detector at 520 nm. The method has a limit of quantitation of 5 ppb monensin in milk and 25 ppb monensin in bovine muscle, liver, kidney, and fat. Standard recovery over the levels and matrixes tested ranged from 80 to 88%. The method is an improvement in specificity, accuracy, and analysis time over existing monensin residue methods for bovine tissues.

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.

Comparison of Postcolumn Derivatization-Liquid Chromatography with Thin-Layer Chromatography for Determination of Aflatoxins in Naturally Contaminated Corn

1990 ◽  
Vol 73 (4) ◽  
pp. 579-581 ◽  
Author(s):  
Rodney W Beaver ◽  
David M Wilson ◽  
Mary W Trucksess
Keyword(s):  
Liquid Chromatography ◽  
Detection Limit ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Correlation Coefficient ◽  
Low Levels ◽  
Aflatoxin B2 ◽  
Layer Chromatography ◽  
Postcolumn Derivatization

Abstract Quantitation of aflatoxins by liquid chromatography with postcolumn iodine derlvatization (LC-PCD) and fluorescence detection was compared with quantitation by the AOAC CB method, 968.22. Thirty-seven naturally contaminated corn samples were ground and then divided. One portion was extracted, and the extract was cleaned up and analyzed by thin-layer chromatography according to the CB method. The second portion was extracted and cleaned up In a similar fashion, but quantitation was by the LC-PCD method. For aflatoxin B1, concentrations ranging from 0 to 150 ng/g, results obtained by the 2 methods were fitted to a linear equation with the LC-PCD results as the dependent variable. The correlation coefficient was 0.99, the Intercept was near 0, and the slope was near 1. For aflatoxin B2, the correlation coefficient was 0.97, and the Intercept was near 0. However, the slope of the equation relating LC-PCD concentration to TLC concentration was only 0.5. We believe that this lack of equivalence between the methods for determination of aflatoxin B2 is due to overestlmatlon by the TLC method because the low levels present are near the TLC detection limit for B2.

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