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.

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 and Gas Chromatographic-Mass Spectrometric Confirmation of Lasalocid Sodium in Bovine Liver: Interlaboratory Study

1989 ◽  
Vol 72 (4) ◽  
pp. 584-586
Author(s):  
Lesley R Frank ◽  
Charlie J Barnes
Keyword(s):  
Bovine Liver ◽  
Chromatographic Determination ◽  
Interlaboratory Study ◽  
Tissue Samples ◽  
Coefficients Of Variation ◽  
Chicken Skin ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Good Agreement ◽  
Chromatographic Mass

Abstract The U.S. Food and Drug Administration (FDA) sponsored an interlaboratory study of a liquid chromatographic determinative procedure for lasalocid sodium in chicken skin with adhering fat. Four laboratories analyzed 35 dosed tissue samples and 82 fortified tissue samples containing lasalocid at levels ranging from 0.1 to 0.6 ppm. Samples were homogenized with acetonitrile, washed with hexane, and partitioned into the mobile phase prior to analysis liquid chromatography with fluorescence detection. The results of the interlaboratory study showed good reproducibility for fortified samples. Fortification levels, average recoveries, and interlaboratory percent coefficients of variation were as follows: 0.6 ppm, 0.57 ppm, and 9.7; 0.3 ppm, 0.25 ppm, and 9.1; and 0.15 ppm, 0.14 ppm, and 7.0, respectively. Data for analysis of the dosed tissue also showed good agreement among the laboratories.

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 Ivermectin in Feed at the 2-PPM Level: Interlaboratory Study

1994 ◽  
Vol 77 (6) ◽  
pp. 1353-1358 ◽  
Author(s):  
David W Fink
Keyword(s):  
Solid Phase ◽  
Chromatographic Determination ◽  
Interlaboratory Study ◽  
Coefficients Of Variation ◽  
Significant Difference ◽  
The Individual ◽  
Liquid Chromatographic ◽  
Medicated Feeds ◽  
Ppm Level

Abstract An analytical method for the determination of ivermectin in feed at the 2 ppm level was evaluated in an interlaboratory study involving 4 laboratories. The method is based on liquid chromatographic measurement following sample preparation by adsorption chromatography on alumina and solid-phase extraction techniques. Each laboratory analyzed 2 complete, final, finished medicated feeds and the corresponding control feeds used in their preparation. In addition, they also measured recoveries in fortified feeds covering 50–150% of the 2 ppm ivermectin use concentration. The mean recoveries from the replicate analyses reported by the laboratories ranged from 90 to 110% and all coefficients of variation (CVs) were less than 4.5%. No significant interferences were found in the control feeds. The pooled distribution of all the 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-laboratories 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).

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.

Liquid Chromatographic Determination of Sulfentrazone in Soil

1999 ◽  
Vol 82 (5) ◽  
pp. 1214-1216 ◽  
Author(s):  
G Anthony Ohmes ◽  
Thomas C Mueller
Keyword(s):  
Chromatographic Determination ◽  
Soil Samples ◽  
Ultraviolet Detection ◽  
Liquid Chromatographic Separation ◽  
Relative Standard ◽  
Limit Of Quantitation ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Soluble Components

Abstract A rapid method for the determination of sulfentrazone in soils is described. The method consists of extraction of soil samples with methanol, filtration, liquid chromatographic separation of methanol-soluble components through a C18 column, and ultraviolet detection at 220 nm. Recoveries from fortified surface soils were >85% for sulfentrazone. Average relative standard deviations over the soils examined was 7.7%. A conservative lower limit of quantitation for sulfentrazone was 40 ng/g soil.

Gas Chromatographic Determination of Captan, Folpet, and Captafol Residues in Tomatoes, Cucumbers, and Apples Using a Wide-Bore Capillary Column: Interlaboratory Study

1991 ◽  
Vol 74 (5) ◽  
pp. 830-835 ◽  
Author(s):  
Dalia M Gilvydis ◽  
Stephen M Walters
Keyword(s):  
Gas Chromatography ◽  
Electron Capture ◽  
Capillary Column ◽  
Chromatographic Determination ◽  
Interlaboratory Study ◽  
Electron Capture Detection ◽  
Coefficients Of Variation ◽  
Capillary Column Gas Chromatography ◽  
Ppm Level

Abstract An interlaboratory study of the determination of captan, folpet, and captafol in tomatoes, cucumbers, and apples was conducted by 4 laboratories using wide-bore capillary column gas chromatography with electron capture detection. The 3 fungicides were determined using the Luke et al. multlresidue method modified to Include additional solvent elutlon in the optional Florisll column cleanup step used with this method. The crops were fortified with each fungicide at 3 levels per crop. Mean recoveries ranged from 86.2% for a 25.1 ppm level of captan in apples to 115.4% for a 0.288 ppm level of captafol In apples. Interlaboratory coefficients of variation ranged from 3.4% (24.7 ppm folpet) to 9.7% (0.243 ppm captafol) for tomatoes; from 2.8% (2.0 ppm captafol) to 8.2% (24.8 ppm captan) for cucumbers; and from 1.5% (0.234 ppm folpet) to 22.1% (0.266 ppm captafol) for apples.

High Performance Liquid Chromatographic Determination of Carbaryl Insecticide in Formulations

1980 ◽  
Vol 63 (3) ◽  
pp. 650-652
Author(s):  
William H Mcdermott
Keyword(s):  
High Performance ◽  
Methylene Chloride ◽  
Collaborative Study ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Modified Silica Gel ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A high performance liquid chromatographic method for carbaryl in formulations has been developed and used to assay 3 formulations in a 10-day repeatability study. The method uses a cyano modified silica gel column packing and a mobile phase of heptane-methylene chloride-isopropanol-methanol (60+35+4.8+0.2). The coefficients of variation for 2 wettable powders and one aqueous flowable formulation were 0.61, 0.62, and 0.75%, respectively. It is recommended that a collaborative study be conducted on this method.

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