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 Fumonisins B1 and B2 in Corn and Corn Flakes by Liquid Chromatography with Immunoaffinity Column Cleanup: Collaborative Study

2001 ◽  
Vol 84 (6) ◽  
pp. 1828-1838 ◽  
Author(s):  
Angelo Visconti ◽  
Michele Solfrizzo ◽  
Annalisa De Girolamo ◽  
H Bresch ◽  
P Burdaspal ◽  
...  
Keyword(s):  
Collaborative Study ◽  
Immunoaffinity Column ◽  
Relative Standard ◽  
Repeatability And Reproducibility ◽  
Double Extraction ◽  
Standard Deviations ◽  
Corn Flakes ◽  
Liquid Chromatographic ◽  
Fumonisins B1 And B2

Abstract A liquid chromatographic (LC) method for the determination of fumonisins B1 (FB1) and B2 (FB2) in corn and corn flakes was collaboratively studied by 23 laboratories, which analyzed 5 blind duplicate pairs of each matrix to establish the accuracy, repeatability, and reproducibility characteristics of the method. Fumonisin levels in the corn ranged from <0.05 (blank) to 1.41 μg/g for FB1 and from <0.05 to 0.56 μg/g for FB2, whereas in the corn flakes they ranged from <0.05 to 1.05 μg/g for FB1 and from <0.05 to 0.46 μg/g for FB2. The method involved double extraction with acetonitrile–methanol–water (25 + 25 + 50), cleanup through an immunoaffinity column, and LC determination of the fumonisins after derivatization with o-phthaldialdehyde. Relative standard deviations for the within-laboratory repeatability (RSDr) of the corn analyses ranged from 19 to 24% for FB1 and from 19 to 27% for FB2; for the corn flakes analyses, RSDr ranged from 9 to 21% for FB1 and from 8 to 22% for FB2. Relative standard deviations for the between-laboratories reproducibility (RSDR) of the corn analyses ranged from 22 to 28% for FB1 and from 22 to 30% for the FB2; for corn flakes analyses, RSDR ranged from 27 to 32% for FB1 and from 26 to 35% for FB2. Mean recoveries of FB1 and FB2 from corn spiked with FB1 at 0.80 μg/g and with FB2 at 0.40 μg/g were 76 and 72%, respectively; for corn flakes spiked at the same levels recoveries were 110 and 97% for FB1 and FB2, respectively. HORRAT ratios for the analyses of corn ranged from 1.44 to 1.53 for FB1 and from 0.96 to 1.48 for FB2, whereas for corn flakes they ranged from 1.60 to 1.82 for FB1 and from 1.39 to 1.68 for FB2.

Liquid Chromatographic Determination of Penicillin V Potassium in Tablets: Collaborative Study

1989 ◽  
Vol 72 (6) ◽  
pp. 883-884
Author(s):  
Barry Mopper
Keyword(s):  
Collaborative Study ◽  
Potassium Phosphate ◽  
Internal Standard ◽  
Photometric Detection ◽  
Penicillin V ◽  
Relative Standard ◽  
Repeatability And Reproducibility ◽  
Standard Deviations ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method for the determination of penicillin V potassium in tablets was collaboratively studied by 7 laboratories. The method uses an octadecyl silane reverse-phase column, a mobile phase of acetonitrile-methanol-O.OlM potassium phosphate monobasic (21 + 4 + 75 v/v/v), photometric detection at 225 nm, and sulfadimethoxine as an internal standard. Each collaborator received 6 samples: powdered composites of 2 commercial tablet preparations and 1 synthetic tablet powder mixture, each with blind duplicates. The mean repeatability and reproducibility relative standard deviations for commercial samples were, respectively, 1.10 and 1.46% (250 mg dosage), and 0.84 and 2.82% (500 mg dosage). The average standard recovery from the synthetic formulation was 99.1%, with repeatability and reproducibility relative standard deviations of 1.30 and 3.66%, respectively. The method has been adopted official first action.

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.

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

1997 ◽  
Vol 80 (4) ◽  
pp. 725-731 ◽  
Author(s):  
Curtis J Schreier ◽  
Robert J Greene ◽  
S Bhandari ◽  
N Britton ◽  
B Greene ◽  
...  
Keyword(s):  
Mobile Phase ◽  
Research Laboratory ◽  
Ammonium Acetate ◽  
Collaborative Study ◽  
Fats And Oils ◽  
Reversed Phase ◽  
Relative Standard ◽  
Standard Deviations ◽  
Liquid Chromatographic

Abstract Ethoxyquin is a chemical antioxidant used in feeds, ingredients, fats, and oils. A liquid chromatographic (LC) method for determination of ethoxyquin was developed. The method involves acetonitrile extraction of the sample and isocratic Cis reversed-phase chromatography with ammonium acetate buffer-acetonitrile as mobile phase and fluorescence detection. A collaborative study of the determination of ethoxyquin in various meals and extruded pet foods was conducted by The lams Company Research Laboratory. Eleven laboratories analyzed 16 samples (including 2 blind duplicates) consisting of 7 meat meals and 9 extruded pet foods. Sample means ranged from 0.25 to 289 ppm. Repeatability standard deviations ranged from 0.08 to 3.2 ppm, and repeatability relative standard deviations ranged from 4.5 to 32%. Reproducibility standard deviations ranged from 0.12 to 13 ppm, and reproducibility relative standard deviations ranged from 4.5 to 55%. The LC method for determination of ethoxyquin in feeds has been adopted first action by AOAC INTERNATIONAL.

Liquid Chromatographic Method for Determination of Diquat and Paraquat Herbicides in Potatoes: Collaborative Study

1993 ◽  
Vol 76 (4) ◽  
pp. 881-887 ◽  
Author(s):  
Brian L Worobey ◽  
◽  
F Béraldin ◽  
G Bruns ◽  
J Embleton ◽  
...  
Keyword(s):  
Ion Pairs ◽  
Collaborative Study ◽  
Reversed Phase ◽  
Negative Control ◽  
Silica Cartridge ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
Repeatability And Reproducibility ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method for the determination of diquat and paraquat herbicides/desiccants in potatoes was collaboratively studied in 6 laboratories. Analytes are extracted from 5 g sample with dilute acid by using a microreflux procedure; the hydrolysate is adjusted to pH 9–10 and passed through a disposable silica cartridge for rapid cleanup and preconcentration. Analytes are separated on a reversed-phase LC column and are measured as their heptanesulfonate ion pairs by UV detection. Each collaborator determined diquat and paraquat at 4 levels (0.05,0.1,0.5, and 1.0 ppm) in blind duplicate samples plus 2 blind negative control samples. Potatoes, obtained from each participant’s region, were spiked by the collaborators with unknown aqueous solutions containing no analyte or a mixture of diquat and paraquat standards. Repeatability and reproducibility relative standard deviations (RSDr and RSDR) averaged 17.1 and 29.0%, respectively, for determination of diquat and 10.8 and 29.5%, respectively, for paraquat. For analysis of standard solutions, RSDr and RSDR values were 6.3 and 12.0%, respectively, for diquat and 7.3 and 13.9%, respectively, for paraquat. Accuracy, measured by comparison with true spiking values (absolute recovery) averaged 77.6 and 76.2% for diquat and paraquat, respectively, and ranged from 71.8 to 88.0% for both compounds. The method was adopted first action by AOAC International.

Liquid Chromatographic Method for Determination of Methamidophos in Technical Products and Pesticide Formulations: CIPAC Collaborative Study

1992 ◽  
Vol 75 (4) ◽  
pp. 698-700
Author(s):  
Alan R Hanks
Keyword(s):  
Collaborative Study ◽  
Reversed Phase ◽  
Liquid Chromatographic Method ◽  
Pesticide Formulations ◽  
Relative Standard ◽  
Aoac Method ◽  
Phase Liquid ◽  
Repeatability And Reproducibility ◽  
Liquid Chromatographic

Abstract A reversed-phase liquid chromatographic (LC) method for the determination of technical methamidophos and 5 different formulated products was collaboratively studied in 18 laboratories. Samples were dissolved in water, separated by LC, and detected at 210 nm. Quantitation was done by peak area measurements. Relative standard deviations for repeatability and reproducibility ranged from 0.35 to 0.80 and from 1.14 to 1.60, respectively. The method has been approved first action by AOAC International as a CIPAC-AOAC method.

scholarly journals Determination of Ochratoxin A in Wine and Beer by Immunoaffinity Column Cleanup and Liquid Chromatographic Analysis with Fluorometric Detection: Collaborative Study

2001 ◽  
Vol 84 (6) ◽  
pp. 1818-1827 ◽  
Author(s):  
Angelo Visconti ◽  
Michelangelo Pascale ◽  
Gianluca Centonze ◽  
E Anklam ◽  
A M Betbeder ◽  
...  
Keyword(s):  
Ochratoxin A ◽  
Red Wine ◽  
Collaborative Study ◽  
White Wine ◽  
Fluorometric Detection ◽  
Immunoaffinity Column ◽  
Relative Standard ◽  
Standard Deviations ◽  
Liquid Chromatographic

Abstract The accuracy, repeatability, and reproducibility characteristics of a liquid chromatographic method for the determination of ochratoxin A (OTA) in white wine, red wine, and beer were established in a collaborative study involving 18 laboratories in 10 countries. Blind duplicates of blank, spiked, and naturally contaminated materials at levels ranging from ≤0.01 to 3.00 ng/mL were analyzed. Wine and beer samples were diluted with a solution containing polyethylene glycol and sodium hydrogen carbonate, and the diluted samples were filtered and cleaned up on an immunoaffinity column. OTA was eluted with methanol and quantified by reversed-phase liquid chromatography with fluorometric detection. Average recoveries from white wine, red wine, and beer ranged from 88.2 to 105.4% (at spiking levels ranging from 0.1 to 2.0 ng/mL), from 84.3 to 93.1% (at spiking levels ranging from 0.2 to 3.0 ng/mL), and from 87.0 to 95.0% (at spiking levels ranging from 0.2 to 1.5 ng/mL), respectively. Relative standard deviations for within-laboratory repeatability (RSDr) ranged from 6.6 to 10.8% for white wine, from 6.5 to 10.8% for red wine, and from 4.7 to 16.5% for beer. Relative standard deviations for between-laboratories reproducibility (RSDR) ranged from 13.1 to 15.9% for white wine, from 11.9 to 13.6% for red wine, and from 15.2 to 26.1% for beer. HORRAT values were ≤0.4 for the 3 matrixes.

Determination of Total Taurine in Pet Foods by Liquid Chromatography of the Dansyl Derivative: Collaborative Study

2000 ◽  
Vol 83 (4) ◽  
pp. 784-788 ◽  
Author(s):  
Kieran McCarthy ◽  
Claudia Hischenhuber ◽  
Neil Joyce ◽  
G Cherix ◽  
C Hischenhuber ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Fluorescence Detection ◽  
Collaborative Study ◽  
Gradient Elution ◽  
Taurine Concentration ◽  
Dansyl Derivative ◽  
Relative Standard ◽  
Standard Deviations ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method for the determination of total taurine in pet foods was evaluated in a collaborative study. Ten laboratories assayed 6 blind duplicate pairs of wet and dry pet foods. The taurine in the 6 sample pairs ranged from low (170 mg/kg) to high (2250 mg/kg) concentrations as is. Collaborators also assayed a sample of known taurine concentration for familiarization purposes. Samples were hydrolyzed to release bound taurine, which was subsequently converted to the dansyl derivative and quantitated by gradient-elution LC with fluorescence detection. Repeatability relative standard deviations, RSDr, ranged from 3.2 to 10.0%; reproducibility relative standard deviations, RSDR, ranged from 6.1 to 16.1%. The method has been adopted Official First Action status by AOAC INTERNATIONAL.

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.

Sign in / Sign up

Export Citation Format

Share Document