Liquid Chromatographic Determination of Ivermectin in Bovine Milk: Interlaboratory Study

1992 ◽  
Vol 75 (4) ◽  
pp. 747-750 ◽  
Author(s):  
Philip James Kijak
Keyword(s):  
Bovine Milk ◽  
Chromatographic Determination ◽  
Interlaboratory Study ◽  
Marker Compound ◽  
Lactating Dairy Cows ◽  
Coefficients Of Variation ◽  
Laboratory Trial ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A laboratory trial was completed for an analytical method that can quantitate the marker residue of ivermectin, 22,23-dihydroavermectin B1a, in bovine milk at 1 ng/mL Currently, ivermectin is not approved for use in lactating dairy cows. In this method, the ivermectin residues are isolated from the milk matrix by a series of liquid-liquid extractions. A fluorescent derivative of the marker compound is prepared and then quantified by liquid chromatography with fluorescence detection. The interlaboratory study was successfully completed by using dosed milk and milk fortified with marker residue at 1,2, and 4 ng/mL. The average recoveries by the 3 participating laboratories were 87,59, and 95% at 1 ng/mL; 90,61, and 96% at 2 ng/mL; and 90,73, and 99% at 4 ng/mL. The concentrations of the marker residue in the dosed milk were 4.3, 3.7, and 4.7 ng/mL; coefficients of variation were 4.0,24.8, and 5.9%, respectively.

Gas-Liquid Chromatographic Determination of Mirex and Photomirex in the Presence of Poly chlorinated Biphenyls: Interlaboratory Study

1980 ◽  
Vol 63 (1) ◽  
pp. 37-42 ◽  
Author(s):  
Ross J Norstrom ◽  
Henry T Won ◽  
Micheline Van Hove Holdrinet ◽  
Patrick G Calway ◽  
Caroline D Naftel
Keyword(s):  
Chromatographic Determination ◽  
Interlaboratory Study ◽  
Gas Liquid Chromatography ◽  
Coefficients Of Variation ◽  
Fuming Nitric Acid ◽  
Liquid Chromatographic Determination ◽  
Repeatability And Reproducibility ◽  
Concentrated Sulfuric Acid ◽  
Liquid Chromatographic

Abstract Mirex and photomirex (8-monohydromirex) were separated from polychlorinated biphenyls (PCBs) and other aromatic compounds by nitration with fuming nitric acid-concentrated sulfuric acid and removal of nitro-PCBs on an alumina microcolumn; the compounds were then determined by gas-liquid chromatography. Recoveries of Mirex and photomirex were 102±8 and 104±5%, respectively, from standard solutions which had a PCB-to-Mirex and photomirex ratio of 1000. Recoveries from fortified, uncontaminated samples of sediment, fish, and eggs averaged 93±7 and 92±3% for Mirex and photomirex, respectively. The coefficients of variation for repeatability and reproducibility averaged 8 and 15%, respectively, in an interlaboratory study conducted by 4 laboratories using extracts of naturally contaminated substrates (sediment, carp, eel, and gull egg). Levels of Mirex in the samples ranged from 0.1 to 8 mg/kg, and levels of PCB ranged from 0.5 to 166 mg/kg.

Liquid Chromatographic Determination of Carhadox in Complete Feeds, Premixes, and Concentrates: Interlaboratory Study

1988 ◽  
Vol 71 (3) ◽  
pp. 484-490
Author(s):  
René M L Aerts ◽  
Geziena A Werdmuller
Keyword(s):  
Chromatographic Determination ◽  
Interlaboratory Study ◽  
Alumina Column ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
A Minor ◽  
Liquid Chromatographic ◽  
Feed Samples

Abstract A liquid chromatographic (LC) method previously published for the determination of carbadox in finished feeds and premixes was slightly modified and tested in an interlaboratory study. The feed samples are extracted with methanol-acetonitrile (50 + 50) after wetting with water. The extracts are purified over a short alumina column. An aliquot of the eluate is analyzed with reverse phase liquid chromatography with ultraviolet detection. Before the actual interlaboratory study, a prestudy with 2 familiarization feed samples was performed. For the interlaboratory study, 2 series of meal and pelleted samples were prepared with carbadox from different suppliers. Eight collaborating laboratories received 6 feed samples previously milled and ground and 4 pelleted samples which had to be ground by the collaborator's in-house method. Collaborators also received 3 carbadox concentrates (about 10% w/w) and 4 premix samples derived from the concentrates (about 1% w/w). Coefficients of variation under reproducibility conditions were 8.3% for meal samples and 4.9% for pellets. A minor but significant effect was noted for the influence of pelleting temperature on the carbadox content. A minor and insignificant effect was observed for the influence of the milling and grinding procedure on the carbadox content. Alumina cleanup of 1% premixes was not essential, although the resulting chromatograms were cleaner. A slight difference in reproducibility was observed with concentrates (10%) when 0.2 or 0.5 g sample size was used, although the average carbadox concentration found was the same. For premixes and concentrates, coefficients of variation under reproducibility conditions were low, ranging from 2.9 to 7.5%.

Liquid Chromatographic Determination of Multiple Sulfonamide Residues in Bovine Milk

1990 ◽  
Vol 73 (6) ◽  
pp. 875-879
Author(s):  
Michael D Smedley ◽  
John D Weber
Keyword(s):  
Bovine Milk ◽  
Potassium Phosphate ◽  
Chromatographic Determination ◽  
Phosphate Solution ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Determination ◽  
Aqueous Layer ◽  
Sulfonamide Residues ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method has been developed for simultaneous determination of residues of 10 sulfonamide drugs at 10 ppb and above In raw bovine milk. The method Is based on a chloroform-acetone extraction, evaporation of organic phase, dissolution of residues in an aqueous potassium phosphate solution, and extraction of fatty residue Into hexane. The aqueous layer is collected, filtered, Injected onto an LC system, and detected by ultraviolet absorption at 265 nm. To elute all 10 sulfonamides Isocratlcally, 2 chromatographic conditions are required. Seven sulfonamides can be quantltated with 12% methanol in the mobile phase; 4 sulfonamides can be quantltated with 30% methanol. Sulfamethazine, the most widely used sulfonamide, Is detected on both systems. Recoveries are 44-87% for Individual sulfonamides, with only 2 below 60%. Coefficients of variation are 3-13% at 10 ppb.

Liquid Chromatographic Determination and Liquid Chromatographic-Thermospray Mass Spectrometric Confirmation of Nicarbazin in Chicken Tissues: Interlaboratory Study

1993 ◽  
Vol 76 (2) ◽  
pp. 420-423 ◽  
Author(s):  
Mary G Leadbetter ◽  
Jean E Matusik ◽  
◽  
W W Koscinski ◽  
M G Leadbetter ◽  
...  
Keyword(s):  
Chromatographic Determination ◽  
Interlaboratory Study ◽  
Ultraviolet Detection ◽  
Tissue Extracts ◽  
Muscle Tissues ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Thermospray Mass Spectrometry ◽  
Ppm Level

Abstract The U.S. Food and Drug Administration sponsored an interlaboratory study of a liquid chromatographic determination with ultraviolet detection of nicarbazin in chicken liver and muscle tissues. The method determined the 4,4’-dinitrocarbanilide(DNC) portion of nicarbazin. The interlaboratory study of the determinative method was successful for nicarbazin at the 4 ppm level. Results showed good reproducibility for the fortified liver and muscle samples. Mean interlaboratory recoveries and percent coefficients of variation at about 4 ppm were 87.1 and 10.9%, respectively, for muscle and 87.4 and 7.5%, respectively, for liver. The interlaboratory analyses of the dosed liver and muscle tissues produced concentration levels similar to those obtained by the sponsor. The confirmatory procedure, which identified DNC in purified tissue extracts, used liquid chromatography-thermospray/mass spectrometry. The confirmatory procedure was successfully evaluated by one FDA laboratory.

High Performance Liquid Chromatographic Determination of Methapyrilene Hydrochloride in Feed and Sleep Aid Tablets

1981 ◽  
Vol 64 (4) ◽  
pp. 889-892
Author(s):  
Badaruddin Shaikh ◽  
Margarette R Hallmark
Keyword(s):  
High Performance ◽  
Ammonium Carbonate ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Reverse Phase ◽  
Phase Partition ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract Methapyrilene hydrochloride (MP·HCl) was extracted from feed with methanol and determined by reverse phase partition chromatography in less than 15 min, using isocratic elution with acetonitrile-1.1% ammonium carbonate (1 + 1) as the mobile phase. This procedure was tested on feed treated with MP·HCl at levels of 125,500, and 2000 ppm. Recoveries were 104,95, and 96% with coefficients of variation of 2.4,1.6, and 0.6%, respectively. MP·HCl in feed was stable for 14 days. This method was also successfully used to determine MP·HCl in 3 sleep aid tablets.

Gas-Liquid Chromatographic Determination of Tetradif on Technical and Formulations: Collaborative Study

1981 ◽  
Vol 64 (4) ◽  
pp. 829-832
Author(s):  
Bram Van Rossum ◽  
Albertus Martijn ◽  
James E Launer ◽  
◽  
E C Calamita ◽  
...  
Keyword(s):  
Collaborative Study ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Flame Ionization ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract The gas-liquid chromatographic determination of tetradifon technical and formulations was collaboratively studied in duplicate with 12 laboratories. Six samples were dissolved in dichloroethane with n-hexacosane as the internal standard, chromatographed on a column of 3% SE-52, and detected by flame ionization. The average coefficients of variation were 1.2% for the 2 technical samples, 1.6% for the 2 wettable powders, and 1.5% for the 2 emulsifiable concentrates. The method has been adopted official first action.

Liquid Chromatographic Determination of Triadimefon in Technical and Formulated Products: Collaborative Study

1985 ◽  
Vol 68 (3) ◽  
pp. 586-589
Author(s):  
Stephen C Slahck
Keyword(s):  
Collaborative Study ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Normal Phase ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Technical Products

Abstract A liquid chromatographic method for the determination of triadimefon (Bayleton™) in triadimefon technical and formulated products has been developed and subjected to a collaborative study with 7 participating collaborators. Formulations were extracted with mobile solvent and analyzed by normal phase chromatography, with 4-chlorophenyl sulfoxide as an internal standard. Collaborators were furnished with standards and samples of technical products, 50% wettable powders, and 25% wettable powders for analysis. Coefficients of variation of the values obtained on these samples were 1.42, 0.82, and 1.05%, respectively. The method has been adopted official first action.

Ion Pairing High Pressure Liquid Chromatographic Determination of Amaranth in Licorice Products

1981 ◽  
Vol 64 (6) ◽  
pp. 1411-1413
Author(s):  
William J Hurst ◽  
James M Mckim ◽  
Robert A Martin
Keyword(s):  
High Pressure ◽  
Ion Pairing ◽  
Chromatographic Determination ◽  
Buffer Solution ◽  
High Pressure Liquid Chromatographic ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A high pressure liquid chromatographic method is described for the determination of amaranth (FD&C Red No. 2; Red No. 2) in licorice products. The Red No. 2 is extracted with a basic buffer solution, cleaned up on a Sep-Pak column, chromatographed on a reverse phase column in the ion pairing mode, and detected at 254 nm. The procedure is time-conservative with accurate and precise results. Recovery data ranged from 93 to 104%, and coefficients of variation were less than 4% for standards and samples.

scholarly journals Liquid Chromatographic Determination of Ivermectin in Feed

1998 ◽  
Vol 81 (4) ◽  
pp. 869-872 ◽  
Author(s):  
Stephen J Doherty ◽  
Allen Fox ◽  
David W Fink
Keyword(s):  
Solid Phase ◽  
Chromatographic Determination ◽  
Phase Extraction ◽  
Coefficients Of Variation ◽  
Significant Difference ◽  
Liquid Chromatographic Determination ◽  
Chromatographic Measurement ◽  
Liquid Chromatographic ◽  
Medicated Feeds

Abstract An analytical method for determining ivermectin in feed at 0.50- 3 ppm is presented. The method is based on liquid chromatographic measurement after sample preparation by adsorption chromatography on alumina and solid-phase extraction. Two complete, final, finished medicated feeds and the corresponding control feeds used in their preparation were analyzed. Recoveries from feeds fortified at 50-150% of the 2 ppm ivermectin use concentration also were determined. Mean recoveries from replicate analyses ranged from 90 to 100%, and coefficients of variation (CVs) were less than 4.5%. No significant interferences were found in control feeds. The pooled distribution of individual analytical results (n = 100) gave a mean recovery of 100%, a recovery range of 90-111%, and an overall CV of 5.5%. Resolution of the total variance into its 2 components gave a withinlaboratory CV of 4.1% and a between-laboratory CV of 3.4%. There was no significant difference in recoveries among laboratories, days, concentrations, and feed base or between fortified and medicated feeds (P > 0.2)

scholarly journals Liquid Chromatographic Determination of Mebendazole and its Metabolites, Aminomebendazole and Hydroxymebendazole, in Eel Muscle Tissue

1996 ◽  
Vol 79 (3) ◽  
pp. 645-651 ◽  
Author(s):  
Christiaan A J Hajee ◽  
Nel Haagsma
Keyword(s):  
Muscle Tissue ◽  
Mobile Phase ◽  
Solid Phase ◽  
Chromatographic Determination ◽  
Extraction Column ◽  
Phase Extraction ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract An analytical method is presented for liquid chromatographic (LC) determination of mebendazole (MBZ), hydroxymebendazole (MBZ-OH), and aminomebendazole (MBZ-NH2) in eel muscle tissue. Muscle tissue is extracted with ethyl acetate at pH 7.5. After addition of n-hexane, the extract is cleaned up and concentrated on an aminopropyl solid-phase extraction column. The test solutions are analyzed isocratically on a ChromSpher B LC column with acetonitrile–phosphate buffer, pH 6.2, as mobile phase. Limits of detection and quantitation were 0.7 and 1.1 ¼g/kg, respectively, for MBZOH; 1.4 and 2.3 ¼g/kg, respectively, for MBZ; and 1.5 and 2.1 ¼g/kg, respectively, for MBZ-NH2. Interand intraday coefficients of variation were 3.5 and 3.4%, respectively, for MBZ-OH; 2.5 and 3.1%, respectively, for MBZ; and 5.8 and 4.8%, respectively, for MBZ-NH2. Mean recoveries were 90% for MBZ, 74% for MBZ-NH2, and 92% for MBZ-OH. A linear range of applicability of at least 10–1000 ¼g/kg was found for each analyte. Incurred MBZ-NH2 (181.3 ¼g/kg) was identified in eel muscle tissue apart from MBZ (23.7 ¼g/kg) after 48 h exposure ina treatment bath containing MBZ at 1 mg/L.

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