scholarly journals Determination of Decoquinate in Animal Feeds by Liquid Chromatography: Collaborative Study

2008 ◽  
Vol 91 (4) ◽  
pp. 685-693 ◽  
Author(s):  
Anivis A Sanchez ◽  
Harold M Campbell ◽  
M S Ahmed ◽  
K Albert ◽  
C Applegate ◽  
...  
Keyword(s):  
Collaborative Study ◽  
The United States ◽  
Reversed Phase ◽  
Excitation Wavelength ◽  
Mechanical Agitation ◽  
Trace Level ◽  
Animal Feeds ◽  
Relative Standard ◽  
Liquid Chromatographic

Abstract The performance characteristics of a liquid chromatographic (LC) method for the analysis of decoquinate (DEC) in supplements, premixes, and complete animal feeds at medicating and trace levels were collaboratively studied. DEC is extracted from ground feed samples with 1 calcium chloridemethanol solution using mechanical agitation for 90 min. After centrifugation for 5 min and dilution (if necessary), an aliquot of the extract is diluted with water. The diluted extracts are filtered and analyzed by reversed-phase LC with fluorescence detection. Suspect positive trace-level samples are confirmed by using an alternate excitation wavelength. Fourteen test samples of medicated feeds, supplement, and medicated premix, along with 8 test samples for trace-level analysis, were sent to 13 collaborators (one in Canada, 4 in Europe, and 8 in the United States). Test samples were analyzed as blind duplicates. Acceptable results were received from 12 laboratories for the medicated test samples and from 13 laboratories for the trace-level samples. Repeatability relative standard deviation estimates ranged from 1.3 to 5.6. Reproducibility relative standard deviations estimates ranged from 2.8 to 6.1, and HorRat values ranged from 0.22 to 0.74.

scholarly journals Determination of Monensin, Narasin, and Salinomycin in Mineral Premixes, Supplements, and Animal Feeds by Liquid Chromatography and Post-Column Derivatization: Collaborative Study

2006 ◽  
Vol 89 (5) ◽  
pp. 1229-1242 ◽  
Author(s):  
Harold Campbell ◽  
Gita Nayeri ◽  
J M Costa ◽  
J deJong ◽  
I Felgueiras ◽  
...  
Keyword(s):  
Collaborative Study ◽  
Reversed Phase ◽  
Hexane Extraction ◽  
Trace Level ◽  
Animal Feeds ◽  
Liquid Chromatographic ◽  
Medicated Feeds ◽  
Reversed Phase Lc ◽  
Level Analysis

Abstract A liquid chromatographic (LC) method for the analysis of monensin, narasin, and salinomycin in mineral premixes, supplements, and complete animal feeds at medicating and trace levels was collaboratively studied. The method uses methanolwater (90 + 10) extraction with mechanical shaking for 1 h, filtration, and dilution if necessary. Determination of the 3 ionophores is by reversed-phase LC using post-column derivatization with vanillin and detection at 520 nm. Suspect positive trace-level products and medicated feeds containing unexpected ionophores are confirmed by hexane extraction or post-column derivatization with dimethylaminobenzaldehyde (DMAB). Twenty-five test samples of medicated feeds, supplements, and mineral and drug premixes, and 9 test samples for trace-level analysis were sent to 11 collaborators in Bulgaria, Czech Republic, Portugal, France, The Netherlands, United States, and Canada. Acceptable results were received from 10 laboratories. For the medicated complete feeds, supplements, and mineral premixes, RSDr values (within-laboratory repeatability) ranged from 2.5 to 5.2%, RSDR values (among-laboratory reproducibility) ranged from 2.7 to 6.8%, and HorRat values ranged from 0.31 to 1.30. For the drug premixes, the result variability was excessive and HorRat values ranged from 2.27 to 14.1. For the trace-level test samples, all laboratories correctly identified the analytes and did not report any false positives. RSDr values ranged from 1.3 to 9.5%, RSDR values ranged from 5.2 to 13.1%, and HorRat values ranged from 0.4 to 0.97.

scholarly journals Liquid Chromatographic Determination of Monensin in Premix and Animal Feeds: Collaborative Study

1997 ◽  
Vol 80 (4) ◽  
pp. 693-702 ◽  
Author(s):  
Mark R Coleman ◽  
John W Moran ◽  
Daniel H Mowrey ◽  
J P Antalick ◽  
D J Bark ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Collaborative Study ◽  
The United States ◽  
Animal Feeds ◽  
Relative Standard ◽  
Cattle Feeds ◽  
Microbiological Assays ◽  
Liquid Chromatographic

Abstract An interlaboratory study of a liquid chromatographic (LC) method for determining monensin in premix (60–80 g/lb or 132–5176 mg/g) and animal feeds (5–200 g/ton or 0.0055–0.22 mg/g) was conducted in laboratoriesin the United States, Canada, France, and Germany. The LC system used a reversed- phase column, postcolumn derivatization with vanillin, and UV detection. The method separates monensin from other ionophores such as narasin and salinomycin. Each laboratory analyzed a total of 20 samples of premix, liquid feed supplements, poultry, and cattle feeds. Concentrations of monensin in all samples ranged from 0 to 176 mg/g (80 g/lb). Reproducibility relative standard deviation (RSDR) for premix ranged from 2.8 to 3.4%. For feed samples containing monensin, repeatability standard deviation (Sr) ranged from 0.9 to 7.0. Reproducibility standard deviation (SR) ranged from 1.2 to 11. Repeatability relative standard deviation (RSDr) ranged from 6.1 to 21% and RSDR valuesranged from 8.6 to 25%. Sample preparation for the LC method is less labor intensive than that for the microbiological assays. The LC assay is more efficient than the microbiological assays. This LC method for determination of monensin in premix and animal feeds has been adopted first action by AOAC INTERNATIONAL.

Liquid Chromatographic Method for Determination of Iodine in Milk: Collaborative Study

1993 ◽  
Vol 76 (4) ◽  
pp. 711-719 ◽  
Author(s):  
David Sertl ◽  
William Malone ◽  
◽  
P Beljaars ◽  
C Blake ◽  
...  
Keyword(s):  
Membrane Filter ◽  
Collaborative Study ◽  
Reversed Phase ◽  
Powdered Milk ◽  
Insoluble Material ◽  
Relative Standard ◽  
Repeatability And Reproducibility ◽  
Standard Deviations ◽  
Liquid Chromatographic

Abstract Nine laboratories participated in an AOAC International/ International Dairy Federation collaborative study on a liquid chromatographic (LC) method for determination of iodine in milk. Liquid milk is passed through a 25 000 MW membrane filter to remove protein and insoluble material. Iodine (in the form of iodide) in the clear filtrate is separated by reversed-phase ion-pair LC and is detected electrochemically. Participants analyzed 2 commercial pasteurized whole milks and 5 nonfat dry milk powders in blind duplicate. Each sample was tested in duplicate on 2 days. Repeatability and reproducibility standard deviations (sr and SR, respectively) and repeatability and reproducibility relative standard deviations (RSDr and RSDR, respectively) for determinations of iodine in whole milk (mean recovery, 86.7%) were as follows: sr, 22 μg/L; SR, 22 μg/L; RSDr, 8.2%; and RSDR, 8.3%. For powdered milk (mean recovery, 91 %), the values were as follows: sr, 0.14 μg/g; SR, 0.22 μg/g; RSDr, 9.0%; and RSDR, 12.7%. The method was adopted first action by AOAC International.

scholarly journals Determination of Patulin in Apple Juice by Liquid Chromatography: Collaborative Study

1996 ◽  
Vol 79 (2) ◽  
pp. 451-455 ◽  
Author(s):  
Allan R Brause ◽  
Mary W Trucksess ◽  
Frederick S Thomas ◽  
Samuel W Page ◽  
J Burke ◽  
...  
Keyword(s):  
Apple Juice ◽  
Fruit Juice ◽  
Collaborative Study ◽  
Test Sample ◽  
Reversed Phase ◽  
International Union ◽  
Relative Standard ◽  
Liquid Chromatographic ◽  
Reversed Phase Lc

Abstract An AOAC International-International Union of Pure and Applied Chemistry-International Fruit Juice Union (AOAC-IUPAC-IFJU) collaborative study was conducted to evaluate a liquid chromatographic (LC) procedure for determination of patulin in apple juice. Patulin is a mold metabolite found naturally in rotting apples. Patulin is extracted with ethyl acetate, treated with sodium carbonate solution, and determined by reversed-phase LC with UV detection at 254 or 276 nm. Water, water-tetrahydrofuran, or water-acetonitrile was used as mobile phase. Levels determined in spiked test samples were 20, 50,100, and 200 μg/L. A test sample naturally contaminated at 31 μg/L was also included. Twenty-two collaborators in 10 countries analyzed 12 test samples of apple juice. Recoveries averaged 96%, with a range of 91-108%. Repeatability relative standard deviations (RSDr) ranged from 10.9 to 53.8%. The reproducibility relative standard deviation (RSDR) ranged from 15.1 to 68.8%. The LC method for determination of patulin in apple juice has been adopted first action by AOAC INTERNATIONAL.

scholarly journals Liquid Chromatographic Determination of the Glycoalkaloids α-Solanine and α-Chaconine in Potato Tubers: NMKL Interlaboratory Study

1997 ◽  
Vol 80 (3) ◽  
pp. 549-554 ◽  
Author(s):  
Karl-Erik Hellenás ◽  
Carina Branzell ◽  
H Poutanen ◽  
T Suortti ◽  
R Kaario ◽  
...  
Keyword(s):  
Collaborative Study ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Potato Tubers ◽  
Photometric Detection ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract Twelve laboratories participated in a collaborative study to evaluate precision parameters of a liquid chromatographic method for analysis of the glycoalkaloids α-solanine and α-chaconine in potato tubers. Samples consisted of frozen potato tuber homogenates distributed as 3 blind duplicates and 3 split-level pairs. The analytical method included aqueous extraction, workup on disposable solidphase extraction cartridges, and reversed-phase chromatography with photometric detection at 202 nm. Results for α-solanine and α-chaconine were received from 10 and 9 laboratories, respectively. Relative standard deviations for reproducibilo ity for α-solanine and α-chaconine were similar, ranging from 8 to 13% in the applied concentration range of 12 to 260 mg/kg fresh weight.

Liquid Chromatographic Method for Determination of Aflatoxins B1, B2, G1, and G2 in Corn and Peanut Products: Collaborative Study

1990 ◽  
Vol 73 (2) ◽  
pp. 260-266 ◽  
Author(s):  
Douglas L Park ◽  
Stanley Nesheim ◽  
Mary W Trucksess ◽  
Michael E Stack ◽  
Richard F Newell
Keyword(s):  
Chromatographic Method ◽  
Peanut Butter ◽  
Collaborative Study ◽  
The United States ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
Standard Deviations ◽  
Contamination Levels ◽  
Liquid Chromatographic

Abstract A collaborative study of a liquid chromatographic method for the determination of aflatoxins B1, B2, G1, and G2 was conducted in laboratories located in the United States, Canada, South Africa, and Switzerland. Twenty-one artificially contaminated raw peanuts, peanut butter, and corn samples containing varying amounts of aflatoxins B1, B2, G1, and G2 were distributed to participating laboratories. The test portion was extracted with methanol-0.1N HCl ( 4 + 1 ) , filtered, defatted with hexane, and then partitioned with methylene chloride. The concentrated extract was passed through a silica gel column. Aflatoxins B1 and G1 were derivatized with trifluoroacetic acid, and the individual aflatoxins were determined by reverse-phase liquid chromatography with fluorescence detection. Statistical analysis of the data was performed to determine or confirm outliers, and to compute repeatability and reproducibility of the method. For corn, relative standard deviations for repeatability (RSDr) for anatoxin B1 ranged from 27.2 to 8.3% for contamination levels from 5 through 50 ng/g. For raw peanuts and peanut butter, RSDr values for aflatoxin Bi were 35.0 to 41.2% and 11.2 to 19.1 %, respectively, for contamination levels from 5 through 25 ng/g. RSDr values for aflatoxins B2, G1, and G2 were similar. Relative standard deviations for reproducibility (RSDR) for aflatoxin B1 ranged from 15.8 to 38.4%, 24.4 to 33.4%, and 43.9 to 54.0% for corn, peanut butter, and raw peanuts, respectively. The method has been adopted official first action for the determination of aflatoxins B1, B2, G1, and G2 in peanut butter and corn at concentrations ≥13 ng total aflatoxlns/g.

Rapid Solvent-Efficient Method for Liquid Chromatographic Determination of Ochratoxin A in Corn, Barley, and Kidney: Collaborative Study

1992 ◽  
Vol 75 (3) ◽  
pp. 481-487 ◽  
Author(s):  
Stanley Nesheim ◽  
Michael E Stack ◽  
Mary W Trucksess ◽  
Robert M Eppley ◽  
Palle Krogh
Keyword(s):  
Ochratoxin A ◽  
Collaborative Study ◽  
Kidney Tissue ◽  
Chromatographic Determination ◽  
The United States ◽  
Relative Standard ◽  
Pork Kidney ◽  
Standard Deviations ◽  
Liquid Chromatographic

Abstract A joint Interlaboratory study of a rapid, solvent-efficient liquid chromatographic method for determination of ochratoxin A (OTA) in barley, corn, and pork kidney tissue was conducted by AOAC, the International Union of Pure and Applied Chemistry, and the Nordic Committee on Food Analysis In 16 laboratories in Europe, Canada, and the United States. OTA was added to barley and corn at 10,20, and 50 ng/g and to kidney at 5,10, and 20 ng/g. Duplicate test portions were prepared at 20 ng/g for corn and barley and 10 ng/g for kidney. Mean recoveries of OTA ranged from 53 to 97%. Within-laboratory relative standard deviations were 7.9,20.1, and 15.7% for barley, corn, and kidney tissue, respectively. Between-laboratories relative standard deviations were 20.7-31.7% for all concentrations of OTA In barley and corn and 68.0,41.8, and 32.7% for OTA concentrations of 5,10, and 20 ng/g, respectively, In kidney. OTA Identity was confirmed by methyl ester derivatization followed by liquid chromatography. The method has been adopted first action by AOAC as quantitative at the levels tested for OTA determination In corn and barley.

Quantitation of Cyfluthrin in Liquid and Solid Formulations by Reversed-Phase Liquid Chromatography: Collaborative Study

1995 ◽  
Vol 78 (6) ◽  
pp. 1335-1338 ◽  
Author(s):  
Donald N Harbin
Keyword(s):  
Collaborative Study ◽  
Internal Standard ◽  
Reversed Phase ◽  
Matched Pair ◽  
Reversed Phase Liquid Chromatography ◽  
Pesticide Formulations ◽  
Relative Standard ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method has been developed for quantitation of cyfluthrin (Baythroid®, Tempo®) in liquid and solid formulations. Cyfluthrin is a synthetic pyrethroid insecticide. Samples are dissolved in acetonitrile and analyzed by reversedphase LC with decanophenone as an internal standard. Seventeen laboratories from 7 countries participated in a collaborative study of the method. Each collaborator was provided with reference standard, internal standard, and matched pair samples of Tempo 20 wettable powder, Tempo 2 emulsifiable concentrate, and Tempo 2 flowable liquid formulations. Collaborators were instructed to use peak area measurements for quantitation. Relative standard deviations for reproducibility (RSDR) were 0.78,0.98, and 2.32, respectively. The LC method for determination of cyfluthrin in pesticide formulations has been adopted first action by AOAC INTERNATIONAL.

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

1994 ◽  
Vol 77 (2) ◽  
pp. 328-330
Author(s):  
Thomas M Schmitt
Keyword(s):  
Collaborative Study ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Relative Standard ◽  
Before And After ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
The Mean ◽  
Liquid Chromatographic

Abstract An isocratic reversed-phase liquid chromatographic (LC) procedure for measuring bentazon in commercial herbicide products and aqueous formulations was collaboratively studied by 16 laboratories. Samples are dissolved in LC eluent [0.075M sodium acetate–methanol (60 + 40)] and analyzed by LC on a 30 cm × 3.9 mm octadecylsilyl column with detection by UV absorbance at 340 nm. The quantity of active ingredient is determined by comparing the mean response factor (RF) of the sample to the mean RF of standards injected just before and after each pair of sample injections. The average relative standard deviation (RSDR) for 3 formulations studied was 1.54%; the RSDR for a technical sample was 0.77%. The method has been adopted first action by AOAC INTERNATIONAL.

Continuous Flow and Liquid Chromatographic Determination of p-Toluenesulfonamide in Ice Cream: Interlaboratory Study

1993 ◽  
Vol 76 (3) ◽  
pp. 570-574 ◽  
Author(s):  
Paul R Beljaars ◽  
Remmelt Van Dijk ◽  
Arie Brands ◽  
◽  
M Anderegg ◽  
...  
Keyword(s):  
Continuous Flow ◽  
Collaborative Study ◽  
Ice Cream ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Relative Standard ◽  
Liquid Chromatographic Determination ◽  
Standard Deviations ◽  
Liquid Chromatographic

Abstract A collaborative study of the continuous flow (CF) and liquid chromatographic determination of p-toluenesulfonamide (p-TSA) in ice cream was conducted by the Project Group on Collaborative Studies (PCS) of the Inspectorate for Health Protection, Food Inspection Service, The Netherlands. The procedure involves extraction of samples with water followed by cleanup of the extracts by dialysis in the CF system. Dialysates are injected by using a loop injector (500 μL) on a reversed-phase octadecylsilane bonded-phase (C18) column, chromatographed with methanol-water (25 + 75, v/v) as mobile phase, and quantitated by fluorescence detection at 230 nm (excitation) and 295 nm (emission). Seven ice-cream samples containing 0-6.35 mg/kg p-TSA at 4 different levels (1 blank and 3 pairs of split-level samples) were singularly analyzed according to the proposed procedure by 11 laboratories. The data were analyzed by the International Union of Pure and Applied Chemistry/ International Organization for Standardization/ AOAC protocol for statistics. No Cochran and Grubbs outliers were found among the participants. For all samples analyzed, repeatability relative standard deviations (RSDr) varied from 2.08 to 3.67%, whereas the reproducibility relative standard deviations (RSDR) ranged from 7.79 to 11.68%. The average p-TSA values for the split levels 1,2, and 3 were 0.55, 1.02, and 4.44 mg p-TSA/kg, respectively, with mean recoveries ranging from 76 to 79% (overall recovery range for all levels, 63-101%). No false-positive results were reported for the blank sample, and no interference was encountered by the presence of vanilla in samples.

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