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

1998 ◽  
Vol 81 (2) ◽  
pp. 344-348 ◽  
Author(s):  
Michelle M Macke ◽  
◽  
Richard Ambrose ◽  
Lajos Benke ◽  
Ralph Denning ◽  
...  
Keyword(s):  
Collaborative Study ◽  
Internal Standard ◽  
Reversed Phase ◽  
Matched Pair ◽  
Reference Standard ◽  
Wettable Powder ◽  
Phase Liquid ◽  
Liquid Chromatographic ◽  
Reversed Phase Lc

abstract A liquid chromatographic (LC) method was developed for quantitation of the synthetic insecticide imidacloprid in liquid and solid formulations. Samples are dissolved or extracted in solvent and analyzed by reversed-phase LC with propiophenone as internal standard. Fourteen laboratories in 7 countries participated in the collaborative study of the method. Each collaborator was provided with reference standard, internal standard, and matched-pair samples of imidacloprid technical, flowable, wettable powder, fertilizer, and granular formulations. Collaborators were instructed to use peak area measurements for quantitation. The reversed-phase LC method for determination of imidacloprid in liquid and solid formulations has been adopted first action by AOAC INTERNATIONAL.

Liquid Chromatographic Method for Determination of Dithianon in Technical Products and Formulations: Collaborative Study

1995 ◽  
Vol 78 (5) ◽  
pp. 1131-1133
Author(s):  
Alan R Hanks
Keyword(s):  
Chromatographic Method ◽  
Collaborative Study ◽  
Reversed Phase ◽  
Study Data ◽  
Water Detection ◽  
Liquid Chromatographic Method ◽  
Phase Liquid ◽  
Liquid Chromatographic ◽  
Technical Products

Abstract A liquid chromatographic method for determination of dithianon in technical products and formulations was evaluated by 22 laboratories participating in a collaborative study. Data received from 19 laboratories were used in the statistical analysis. The study included 3 technical grade materials, 1 suspension concentrate, and 1 wettable powder. Dithianon is determined by reversed-phase liquid chromatography on a C18 column with a mobile phase of acetonitrile and water. Detection at 254 nm with peak area measurements is used with an external standard for quantitation of dithianon. The liquid chromatographic method for determination of dithianon in technical products and formulations has been adopted first action by AOAC INTERNATIONAL.

scholarly journals Determination of D-Malic Acid in Apple Juice by Liquid Chromatography: Collaborative Study

1996 ◽  
Vol 79 (1) ◽  
pp. 50-54 ◽  
Author(s):  
Thomas A Eisele ◽  
K Adadevoh ◽  
G Anderson ◽  
A Brause ◽  
D Briesmeister ◽  
...  
Keyword(s):  
Malic Acid ◽  
Apple Juice ◽  
Copper Acetate ◽  
Collaborative Study ◽  
Reversed Phase ◽  
Uv Detector ◽  
Paired Samples ◽  
Study Results ◽  
Liquid Chromatographic

Abstract Eleven laboratories collaboratively studied a liquid chromatographic (LC) method for determination of D-malic acid in apple juice. The mobile phase consisted of 16 mM L-valine and 8 mM copper acetate adjusted to pH 5.5 with NaOH. The UV detector was set at 330 nm, and a single reversed-phase LC column was used. Seven paired samples containing various amounts of D-malic acid ranging from 0 to 188 mg/100 mL of 12 Brix pasteurized apple juice were tested by each collaborator. Repeatability and reproducibility coefficients of variation ranged from 1.0 to 3.5% and 7.7 to 11.7%, respectively, within the range of 26 to 188 mg D-malic acid/100 mL of 12 Brix apple juice. The collabora tive study results demonstrated that the method could quantitate the economic adulteration of ap ple juice with DL-malic acid at lower levels than those reported with previous methods. The LC method for determination of D-malic acid in apple juice 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.

Gradient Multipeak Liquid Chromatographic Method for Determination of Ardacin in Bulk Chemical and Premix Formulations

1995 ◽  
Vol 78 (2) ◽  
pp. 289-293
Author(s):  
Hafez Abdel-Kader ◽  
Myriam M Kobylkevich ◽  
Larry S Wigman ◽  
Govind K Menon
Keyword(s):  
Pilot Scale ◽  
Reversed Phase ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
External Standard ◽  
Bulk Chemical ◽  
Method Accuracy ◽  
Liquid Chromatographic ◽  
Reversed Phase Lc

Abstract A liquid chromatographic (LC) method was developed for the determination of ardacin in bulk chemical (78 to 100%, w/w anhydrous) and premix formulations (3.3 to 26.4%, w/w). The method is based on reversed-phase LC resolution of ardacin components and detection by UV absorbance at 220 nm. Ardacin has 10 components, and each component can be quantitated separately. Total ardacin is determined by summing the areas of the 10 component peaks. Calculations are performed using an external standard approach. The method is linear for ardacin at 50 to 150 μ/mL. The method accuracy for a typical bulk chemical is ± 1.5%, w/w (relative standard deviation [RSD], 1.6%), and recovery from a typical pilot scale premix is 99.9% (RSD, 3.4%). The method is useful for monitoring stability during storage.

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 Determination of Vitamin D in Animal Feeds and Premixes

1992 ◽  
Vol 75 (5) ◽  
pp. 812-814 ◽  
Author(s):  
Vipin K Agarwal
Keyword(s):  
Vitamin D ◽  
Mobile Phase ◽  
Potassium Hydroxide ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Ultraviolet Detection ◽  
Animal Feeds ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method has been developed for the determination of vitamin D (D2 + D3) in animal feeds and premixes. The sample is saponified with potassium hydroxide, and vitamin D is extracted with hexane and isomerized to isotachysterol with 10M HCI in 2-butanol. LC determination of isotachysterol to quantitate vitamin D is carried out on a reversed-phase column with acetonitrilemethanol (90 +10) as the mobile phase and ultraviolet detection at 301 nm. The detection limit of the method is 1 lU/g. This method can also be used for the determination of vitamin D2 and D3 separately.

scholarly journals Simultaneous Determination of Residues of Chloramphenicol, Thiamphenicol, Florfenicol, and Florfenicol Amine in Farmed Aquatic Species by Liquid Chromatography/Mass Spectrometry

2003 ◽  
Vol 86 (3) ◽  
pp. 510-514 ◽  
Author(s):  
Jeffery M van de Riet ◽  
Ross A Potter ◽  
Melissa Christie-Fougere ◽  
B Garth Burns
Keyword(s):  
Reversed Phase ◽  
Organic Layer ◽  
Aquatic Species ◽  
Liquid Chromatography Mass Spectrometry ◽  
Relative Standard ◽  
Aqueous Layer ◽  
Operational Errors ◽  
Liquid Chromatographic ◽  
Reversed Phase Lc

Abstract A liquid chromatographic (LC)/mass spectrometric (MS) method was developed for determining the residues of chloramphenicol, thiamphenicol, florfenicol, and florfenicol amine in a number of aquatic species. The phenicols are extracted with acetone, the extracts are partitioned with dichloromethane, the aqueous layer is removed, and the organic layer is evaporated to dryness. The residue is dissolved in dilute acid and defatted with hexane, and the aqueous layer is prepared for analysis by LC. The phenicols are determined by reversed-phase LC by using a Hypersil C18-BD column with a water–acetonitrile gradient and MS detection using selectedion recording. Calibration curves were linear for all analytes between 0.015 and 0.425 ng injected. The relative standard deviations for measurements by the proposed method were <10% for all of the analytes studied, with re-coveries ranging from 71% for florfenicol amine to 107% for florfenicol in salmon tissue spiked at the 2 ng/g level. Detection limits of 0.1 ng/g for florfenicol and chloramphenicol, 0.3 ng/g for thiamphenicol, and 1.0 ng/g for florfenicol amine are easily obtainable. The operational errors, interferences, and recoveries for spiked samples compare favorably with those obtained by established LC methodology. The proposed method is simple, rapid, and specific for monitoring residues of chloramphenicol, thiamphenicol, florfenicol, and florfenicol amine in a number of aquatic species.

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