scholarly journals Determination of Clopidol Residues in Chicken Tissues by Liquid Chromatography: Collaborative Study

2003 ◽  
Vol 86 (4) ◽  
pp. 685-693 ◽  
Author(s):  
Guo-Fang Pang ◽  
Yan-Zhong Cao ◽  
Chun-Lin Fan ◽  
Jin-Jie Zhang ◽  
Xue-Min Li ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Solid Phase ◽  
Collaborative Study ◽  
Reversed Phase ◽  
Method Performance ◽  
Chicken Muscle ◽  
Relative Standard

Abstract Eighteen laboratories participated in a collaborative study on the determination of clopidol residues in chicken muscle tissues by liquid chromatography. Of these, results from 16 laboratories which rigorously followed the method were subjected to statistical analysis. The method performance was assessed by all participants using 14 samples of chicken muscle fortified at concentrations ranging from 0.1 to 5.0 mg/kg. In addition, 9 participants each reported results for 6 clopidol-incurred samples in chicken muscle. Test portions were extracted with acetonitrile, and the extracts were purified with alumina and anion exchange resin solid-phase extraction cartridges in sequence. Clopidol was separated by reversed-phase liquid chromatography and quantified at 270 nm. Average recoveries ranged from 81.8 to 85.4%, reproducibility relative standard deviation (RSDR) ranged from 11.9 to 22.6%, and repeatability relative standard deviation (RSDr) ranged from 9.9 to 15.1%. For clopidol-incurred samples at concentrations of 0.100–0.687 mg/kg, the mean determination value range was 0.099–0.659 mg/kg; RSDR was 12.6–19.8%, RSDr was 3.1–8.5%; and HORRAT values were 0.7–1.1. The accuracy and precision of the method are in conformity with the requirements specified by AOAC INTERNATIONAL. The method was adopted Official First Action in April 2003.

scholarly journals Indirect and Direct Determination of the Casein Content of Milk by Kjeldahl Nitrogen Analysis: Collaborative Study

1998 ◽  
Vol 81 (4) ◽  
pp. 763-774 ◽  
Author(s):  
Joanna M Lynch ◽  
David M Barbano ◽  
J Richard Fleming
Keyword(s):  
Standard Deviation ◽  
Nitrogen Content ◽  
Relative Standard Deviation ◽  
Collaborative Study ◽  
Direct Determination ◽  
Raw Milk ◽  
Method Performance ◽  
Relative Standard ◽  
Milk Casein

Abstract The classic method for determination of milk casein is based on precipitation of casein at pH 4.6. Precipitated milk casein is removed by filtration and the nitrogen content of either the precipitate (direct casein method) or filtrate (noncasein nitrogen; NCN) is determined by Kjeldahl analysis. For the indirect casein method, milk total nitrogen (TN; Method 991.20) is also determined and casein is calculated as TN minus NCN. Ten laboratories tested 9 pairs of blind duplicate raw milk materials with a casein range of 2.42- 3.05℅ by both the direct and indirect casein methods. Statistical performance expressed in protein equivalents (nitrogen ⨯ 6.38) with invalid and outlier data removed was as follows: NCN method (wt%), mean = 0.762, sr = 0.010, SR = 0.016, repeatability relative standard deviation (RSDr) = 1.287℅, reproducibility relative standard deviation (RSDR) = 2.146%; indirect casein method (wt℅), mean = 2.585, repeatability = 0.015, reproducibility = 0.022, RSDr = 0.560℅, RSDR = 0.841; direct casein method (wt℅), mean = 2.575, sr = 0.015, sR = 0.025, RSDr = 0.597℅, RSDR = 0.988℅. Method performance was acceptable and comparable to similar Kjeldahl methods for determining nitrogen content of milk (Methods 991.20, 991.21,991.22, 991.23). The direct casein, indirect casein, and noncasein nitrogen methods have been adopted by AOAC INTERNATIONAL.

Determination of p-Toluenesulfonamide in Ice Cream by Combination of Continuous Flow and Liquid Chromatography: Summary of Collaborative Study

1994 ◽  
Vol 77 (3) ◽  
pp. 672-674 ◽  
Author(s):  
Paul R Beuaars ◽  
Remmelt Van Dijk ◽  
Arie Brands
Keyword(s):  
Liquid Chromatography ◽  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Continuous Flow ◽  
Collaborative Study ◽  
Ice Cream ◽  
Relative Standard ◽  
On Line ◽  
Positive Results

Abstract A collaborative study of the determination of p-tolu-enesulfonamide (p-TSA) in ice cream by a combination of continuous flow and on-line liquid chromatography was conducted. Seven ice cream samples containing 0-6.35 mg p-TSA/kg at 4 levels (1 blank and 3 pairs of split level samples) were analyzed by 11 laboratories. For all samples analyzed, the repeatability relative standard deviation varied from 2.08 to 3.67%, whereas the reproducibility relative standard deviation 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 vanillin in samples. The method has been adopted first action by AOAC INTERNATIONAL.

Multifunctional Column Coupled with Liquid Chromatography for Determination of Aflatoxins B1, B2, G1, and G2 in Corn, Almonds, Brazil Nuts, Peanuts, and Pistachio Nuts: Collaborative Study

1994 ◽  
Vol 77 (6) ◽  
pp. 1512-1521 ◽  
Author(s):  
Mary W Trucksess ◽  
Michael E Stack ◽  
Stanley Nesheim ◽  
Richard H Albert ◽  
Thomas R Romer
Keyword(s):  
Liquid Chromatography ◽  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Collaborative Study ◽  
The United States ◽  
Test Portion ◽  
Brazil Nuts ◽  
Pistachio Nuts ◽  
Relative Standard

Abstract An AOAC/IUPAC collaborative study was conducted to evaluate the effectiveness of a multifunctional column for the determination of aflatoxins. The test portion is extracted with acetonitrile–water (9 + 1), the extract is filtered, and the filtrate is passed through the column. The aflatoxins in the eluate are determined by reversed-phase liquid chromatography after derivatization with trifluoroacetic acid. Naturally contaminated corn, almonds, Brazil nuts, peanuts, and pistachio nuts spiked with total aflatoxins at 5,10,20, and 30 ng/g were sent to 12 collaborators in the United States, Denmark, France, Japan, and Switzerland. Eleven collaborators completed the study. Average recoveries of total aflatoxins for each spike level for the various commodities (excluding Brazil nuts at 5 ng/g) were 93,97,95, and 95%, respectively; the repeatability relative standard deviation (RSDr) ranged from 6.0 to 23.2% and the reproducibility relative standard deviation (RSDR) ranged from 12.0 to 69.4%. The multifunctional column coupled with a liquid chromatographic method for determination of aflatoxins in corn, almonds, Brazil nuts, peanuts, and pistachio nuts has been adopted first action by AOAC INTERNATIONAL.

scholarly journals Determination of Aflatoxin B1 in Baby Food (Infant Formula) by Immunoaffinity Column Cleanup Liquid Chromatography with Postcolumn Bromination: Collaborative Study

2001 ◽  
Vol 84 (4) ◽  
pp. 1116-1124 ◽  
Author(s):  
Joerg Stroka ◽  
Elke Anklam ◽  
Urban Joerissen ◽  
John Gilbert ◽  
A Barmark ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Infant Formula ◽  
Aflatoxin B1 ◽  
Collaborative Study ◽  
Baby Food ◽  
Immunoaffinity Column ◽  
Relative Standard

Abstract A collaborative study was conducted to evaluate the effectiveness of an immunoaffinity column cleanup liquid chromatography (LC) method for determination of aflatoxin B1 in a milk powder based infant formula at a possible future European regulatory limit (0.1 ng/g). The test portion was extracted with methanol–water (8 + 2 [v + v]), filtered, diluted with water, and applied to an immunoaffinity column. The column was washed with water to remove interfering compounds, and the purified aflatoxin B1 was eluted with methanol. The separation and determination of the aflatoxin B1 was performed by reversed-phase LC and detected by fluorescence after postcolumn derivatization (PCD) involving bromination. PCD was achieved with either pyridinum hydrobromide perbromide (PBPB) or an electrochemical (Kobra) cell by addition of bromide to the mobile phase. The baby food (infant formula) test samples, both spiked and naturally contaminated with aflatoxin B1, were sent to 14 laboratories in 13 different European countries. Test portions were spiked at levels of 0.1 and 0.2 ng/g for aflatoxin B1. Recoveries ranged from 101 to 92%. Based on results for spiked test samples (blind pairs at 2 levels) and naturally contaminated test samples (blind pairs at 3 levels), the relative standard deviation for repeatability (RSDr) ranged from 3.5 to 14%. The relative standard deviation for reproducibility (RSDR) ranged from 9 to 23%. Nine participants used PBPB derivatization, and 5 particpants used the Kobra cell. There was no evidence of method performance depending on the derivatization method used. The method showed acceptable within- and between-laboratory precision for baby food matrix, as evidenced by HORRAT values, at the target levels of determination for aflatoxin B1.

scholarly journals Immunoaffinity Column Cleanup with Liquid Chromatography for Determination of Aflatoxin M1 in Liquid Milk: Collaborative Study

2001 ◽  
Vol 84 (2) ◽  
pp. 437-443 ◽  
Author(s):  
Sylviane Dragacci ◽  
Frederic Grosso ◽  
John Gilbert ◽  
M Agnedal ◽  
L Hyndrick ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Collaborative Study ◽  
Aflatoxin M1 ◽  
Immunoaffinity Column ◽  
Precision Data ◽  
Relative Standard ◽  
Liquid Milk

Abstract A collaborative study was conducted to evaluate the effectiveness of an immunoaffinity column cleanup liquid chromatographic method for determination of aflatoxin M1 in milk at proposed European regulatory limits. The test portion of liquid milk was centrifuged, filtered, and applied to an immunoaffinity column. The column was washed with water, and aflatoxin was eluted with pure acetonitrile. Aflatoxin M1 was separated by reversed-phase liquid chromatography (LC) with fluorescence detection. Frozen liquid milk samples both naturally contaminated with aflatoxin M1 and blank samples for spiking, were sent to 12 collaborators in 12 different European countries. Test portions of samples were spiked at 0.05 ng aflatoxin M1 per mL. After removal of 2 noncompliant sets of results, the mean recovery of aflatoxin M1 was 74%. Based on results for spiked samples (blind pairs at 1 level) and naturally contaminated samples (blind pairs at 3 levels) the relative standard deviation for repeatability (RSDr) ranged from 8 to 18%. The relative standard deviation for reproducibility (RSDR) ranged from 21 to 31%. The method showed acceptable within- and between-laboratory precision data for liquid milk, as evidenced by HORRAT values at the low level of aflatoxin M1 contamination.

scholarly journals Immunoaffinity Column Cleanup with Liquid Chromatography Using Post-Column Bromination for Determination of Aflatoxin B1 in Cattle Feed: Collaborative Study

2003 ◽  
Vol 86 (6) ◽  
pp. 1179-1186 ◽  
Author(s):  
Joerg Stroka ◽  
Christoph von Holst ◽  
Elke Anklam ◽  
Matthias Reutter ◽  
A Barmark ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Aflatoxin B1 ◽  
Collaborative Study ◽  
Immunoaffinity Column ◽  
Test Portion ◽  
Cattle Feed ◽  
Relative Standard

Abstract A collaborative study was conducted to evaluate the effectiveness of an immunoaffinity column cleanup liquid chromatography (LC) method for determination of aflatoxin B1 in cattle feed at a possible future European regulatory limit (1 ng/g). The test portion was extracted with acetone–water (85 + 15), filtered, diluted with water, and applied to an immunoaffinity column. The column was washed with water to remove interfering compounds, and the purified aflatoxin B1 was eluted with methanol. Aflatoxin B1 was separated and determined by reversed-phase liquid chromatography (RP–LC) and detected by fluorescence after post column derivatization (PCD) involving bromination. PCD was achieved with either pyridinium hydrobromide perbromide (PBPB), used by 14 laboratories, or an electrochemical cell and addition of bromide to the mobile phase, used by 7 laboratories. Both derivatization techniques were not significantly different when compared by the t-test; the method was statistically evaluated for all laboratories together (bromination and PBPB). The cattle feed samples, both spiked and naturally contaminatedwithaflatoxinB1, were sent to 21 laboratories in 14 different countries (United States, Japan, and Europe). Test portions were spiked at levels of 1.2 and 3.6 ng/g for aflatoxin B1. Recoveries ranged from 74 to 157%. Based on results for spiked samples (blind pairs at 2 levels) as well as naturally con-taminated samples (blind pairs at 3 levels), the relative standard deviation for repeatability (RSDr) ranged from 5.9 to 8.7%. The relative standard deviation for reproducibility (RSDR) ranged from 17.5 to 19.6%. The method showed acceptable within-and between-laboratory precision for this matrix, as evidenced by HORRAT values, at the target levels of determination for aflatoxin B1. No major differences in RSD were observed, showing that the composition of the feeds was not a factor for the samples tested and that the method was applicable for all materials used.

Immunoaffinity Column Coupled with Solution Fluorometry or Liquid Chromatography Postcolumn Derivatization for Determination of Aflatoxins in Corn, Peanuts, and Peanut Butter: Collaborative Study

1991 ◽  
Vol 74 (1) ◽  
pp. 81-88 ◽  
Author(s):  
Mary W Trucksess ◽  
Michael E stack ◽  
Stanley Nesheim ◽  
Samuel W Page ◽  
Richard H Albert ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Peanut Butter ◽  
Collaborative Study ◽  
The United States ◽  
Affinity Column ◽  
Immunoaffinity Column ◽  
Relative Standard

Abstract An AOAC/IUPAC (International Union of Pure and Applied Chemistry) collaborative study was conducted to evaluate the effectiveness of an immunoaffinity column for the determination of af latoxin. The test portion Is extracted with methanol- water (7 + 3), filtered, diluted to ⦟30% methanol with water, and applied to the affinity column. The column Is washed with water and the concentrated aflatoxins are eluted with methanol. Total aflatoxins are determined by solution fluorometry with bromine (SFB), and Individual toxins are determined by reverse-phase liquid chromatography with postcolumn derlvatizatlon with Iodine (PCD). Corn naturally contaminated with aflatoxins, and peanuts, peanut butter, and corn containing added aflatoxins ( B1:B2:G1G2 = 7:1:3:1) were sent to 24 collaborators In the United States, France, Canada, and the Republic of South Africa. Twelve collaborators used the SFB method, 9 used the PCD method, and 3 used both SFB and PCD methods. Twenty collaborators completed the study (10 used the SFB method, 7 used the PCD method, and 3 used both SFB and PCD methods). Test portions were spiked at 10, 20, and 30 ng/g. For SFB analyses, recoveries of total aflatoxins were 123,105, and 107%, respectively; the relative standard deviation for repeatability (RSDr) ranged from 11.75 to 16.57%, and the relative standard deviation for reproducibility (RSDR) ranged from 10.97 to 33.09%. For PCD analyses, recoveries were 81, 81, and 83%, respectively; the RSDr ranged from 5.20 to 17.22%, and the RSDR ranged from 4.68 to 50.77%. The RSDr for aflatoxins B1, and G1 for spiked test portions ranged from 5.45 to 23.55%, and the RSDR ranged from 4.21 to 57.28%. The RSDr and RSDR for aflatoxins B2 and G2 were higher because of the small amounts added. Analyses by both SFB and PCD methods showed acceptable within-laboratory and betweenlaboratories precision. The method has been adopted official first action by AOAC as an AOAC-IUPAC method.

scholarly journals Determination of Phytase Activity in Feed by a Colorimetric Enzymatic Method: Collaborative Interlaboratory Study

2001 ◽  
Vol 84 (3) ◽  
pp. 629-633 ◽  
Author(s):  
Adrianus J Engelen ◽  
Fred C van der Heeft ◽  
Peter H G Randsdorp ◽  
Wim A C Somers ◽  
Jan Schaefer ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Colorimetric Assay ◽  
Collaborative Study ◽  
Phytase Activity ◽  
Activity Levels ◽  
Method Performance ◽  
Relative Standard ◽  
Commercial Supplier

Abstract Fourteen laboratories participated in a collaborative study (coded fyt9404) and 13 laboratories participated in a study (coded fyt9410) to validate a colorimetric assay for determination of microbial phytase activity in feed. For each study, all laboratories received 6 laboratory samples provided by one commercial supplier (phytase activity levels within the range of 200–400 per kg) to be analyzed in duplicate. Method performance was calculated and statistical calculations were executed according to AOAC guidelines. Results from 3 laboratories for study fyt9404 and from one laboratory for study fyt9410 were excluded from statistical analysis because of invalid data determined during initial review by Youden pair, value versus laboratory. For study fyt9404, repeatability relative standard deviation (RSDr) values ranged from 6.2 to 8.6%, and reproducibility relative standard deviation (RSDR) values ranged from 14.1 to 27.6%. No outliers were identified. For study fyt9410, RSDr values ranged from 3.9 to 7.9%, and RSDR values ranged from 14.0 to 20.5%. With outliers excluded, RSDr values ranged from 2.5 to 7.9%, and RSDR values ranged from 14.0 to 20.5%.

scholarly journals Immunoaffinity Column Cleanup with Liquid Chromatography Using Post-Column Bromination for Determination of Aflatoxins in Peanut Butter, Pistachio Paste, Fig Paste, and Paprika Powder: Collaborative Study

2000 ◽  
Vol 83 (2) ◽  
pp. 320-340 ◽  
Author(s):  
Joerg Stroka ◽  
Elke Anklam ◽  
Urban Jörissen ◽  
John Gilbert ◽  
Anna Barmark ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Aflatoxin B1 ◽  
Peanut Butter ◽  
Collaborative Study ◽  
Immunoaffinity Column ◽  
Sample Extract ◽  
Relative Standard

Abstract A collaborative study was conducted to evaluate the effectiveness of an immunoaffinity column cleanup liquid chromatography (LC) method for the determination of aflatoxin B1 and total aflatoxins at European regulatory limits. The test portion is extracted with methanol–water (8 + 2) for dried figs and paprika, and with methanol–water (8 + 2) plus hexane (or cyclohexane) for peanut butter and pistachios. The sample extract is filtered, diluted with phosphate buffer saline, and applied to an immunoaffinity column. The column is washed with water and the aflatoxins are eluted with methanol. Aflatoxins are quantitated by reversed-phase LC with post-column derivatization (PCD) involving bromination. PCD is achieved with either an electrochemical cell (Kobra cell) and addition of bromide to the mobile phase or pyridinium hydrobromide perbromide. Determination is by fluorescence. Peanut butter, pistachio paste, dried fig paste, and paprika powder samples, both naturally contaminated with aflatoxins and containing added aflatoxins, were sent to 16 collaborators in 16 European countries. Test portions of samples were spiked at levels of 2.4 and 9.6 ng/g for total aflatoxins which included 1.0 and 4.0 ng/g aflatoxin B1, respectively. Recoveries for total aflatoxins ranged from 71 to 92% with corresponding recoveries for aflatoxin B1 of 82 to 109%. Based on results for spiked samples (blind duplicates at 2 levels) as well as naturally contaminated samples (blind duplicates at 4 levels, including blank), the relative standard deviation for repeatability ranged from 4.6 to 23.3% for total aflatoxins and from 3.1 to 20.0% for aflatoxin B1. The relative standard deviation for reproducibility ranged from 14.1 to 34.2% for total aflatoxins, and from 9.1 to 32.2% for aflatoxin B1. The method showed acceptable within-laboratory and between-laboratory precision for all 4 matrixes, as evidenced by HORRAT values <1, at the low levels of determination for both total aflatoxins and aflatoxin B1.

scholarly journals Determination of Zearalenone and Trichothecenes, Including Deoxynivalenol and Its Acetylated Derivatives, Nivalenol, T-2 and HT-2 Toxins, in Wheat and Wheat Products by LC-MS/MS: A Collaborative Study

Toxins ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 786
Author(s):  
Annalisa De Girolamo ◽  
Biancamaria Ciasca ◽  
Michelangelo Pascale ◽  
Veronica M.T. Lattanzio
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
High Performance ◽  
Solid Phase ◽  
Collaborative Study ◽  
Extraction Column ◽  
Internal Standards ◽  
Relative Standard ◽  
Wheat Products

An analytical method for the simultaneous determination of trichothecenes—namely, nivalenol (NIV), deoxynivalenol (DON) and its acetylated derivatives (3- and 15-acetyl-DON), T-2 and HT-2 toxins—and zearalenone (ZEN) in wheat, wheat flour, and wheat crackers was validated through a collaborative study involving 15 participants from 10 countries. The validation study, performed within the M/520 standardization mandate of the European Commission, was carried out according to the IUPAC (International Union of Pure and Applied Chemistry) International Harmonized Protocol. The method was based on mycotoxin extraction from the homogenized sample material with a mixture of acetonitrile-water followed by purification and concentration on a solid phase extraction column. High-performance liquid chromatography coupled with tandem mass spectrometry was used for mycotoxin detection, using isotopically labelled mycotoxins as internal standards. The tested contamination ranges were from 27.7 to 378 μg/kg for NIV, from 234 to 2420 μg/kg for DON, from 18.5 to 137 μg/kg for 3-acetyl-DON, from 11.4 to 142 μg/kg for 15-acetyl-DON, from 2.1 to 37.6 μg/kg for T-2 toxin, from 6.6 to 134 μg/kg for HT-2 toxin, and from 31.6 to 230 μg/kg for ZEN. Recoveries were in the range 71–97% with the lowest values for NIV, the most polar mycotoxin. The relative standard deviation for repeatability (RSDr) was in the range of 2.2–34%, while the relative standard deviation for reproducibility (RSDR) was between 6.4% and 45%. The HorRat values ranged from 0.4 to 2.0. The results of the collaborative study showed that the candidate method is fit for the purpose of enforcing the legislative limits of the major Fusarium toxins in wheat and wheat-based products.

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