scholarly journals Liquid Chromatographic Method with Immunoaffinity Column Cleanup for Determination of Ochratoxin A in Barley: Collaborative Study

2000 ◽  
Vol 83 (6) ◽  
pp. 1377-1383 ◽  
Author(s):  
A Catherine Entwisle ◽  
Alison C Williams ◽  
Peter J Mann ◽  
Philip T Slack ◽  
John Gilbert
Keyword(s):  
Standard Deviation ◽  
Ochratoxin A ◽  
Relative Standard Deviation ◽  
Limit Of Detection ◽  
Collaborative Study ◽  
Immunoaffinity Column ◽  
Low Level ◽  
Relative Standard ◽  
Liquid Chromatographic

Abstract A collaborative study was conducted to evaluate a liquid chromatographic (LC) method with immunoaffinity column cleanup for determination of ochratoxin A. The method was tested at 3 concentration levels of ochratoxin A in barley, which represent possible future European regulatory limits. The test portion was extracted with acetonitrile–water by blending at high speed. The extract was filtered, diluted with phosphate-buffered saline (PBS), and applied to an ochratoxin A immunoaffinity column. The column was washed with water and the ochratoxin A eluted with methanol. The solvent was then evaporated and the residue redissolved in injection solvent. After injection of this solution onto reversed-phase LC column, ochratoxin A was measured by fluorescence detection. Eight samples of low level naturally contaminated barley and 2 samples of blank barley (ochratoxin A not found at the limit of detection of 0.2 μg/kg at the signal-to-noise ratio of 3 to 1) were sent, along with ampules of ochratoxin A, calibrant, and spiking solutions, to 15 laboratories in 13 different European countries. Test portions were spiked with ochratoxin A at levels of 4 ng/g, and recoveries ranged from 65 to 113%. Based on results for spiked samples (blind duplicates) and naturally contaminated samples (blind duplicates at 3 levels), the relative standard deviation for repeatability (RSDr) ranged from 4 to 24%, and the relative standard deviation for reproducibility (RSDR) ranged from 12 to 33%. The method showed acceptable within- and between-laboratory precision, as evidenced by HORRAT values, at the low level of determination for ochratoxin A in barley.

scholarly journals Combined Phenyl Silane and Immunoaffinity Column Cleanup with Liquid Chromatography for Determination of Ochratoxin A in Roasted Coffee: Collaborative Study

2001 ◽  
Vol 84 (2) ◽  
pp. 444-450 ◽  
Author(s):  
A Catherine Entwisle ◽  
Alison C Williams ◽  
Peter J Mann ◽  
Joanne Russell ◽  
Philip T Slack ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Standard Deviation ◽  
Ochratoxin A ◽  
Relative Standard Deviation ◽  
Collaborative Study ◽  
Immunoaffinity Column ◽  
Roasted Coffee ◽  
Test Portion ◽  
Low Level ◽  
Relative Standard

Abstract A collaborative study was conducted to evaluate a liquid chromatography (LC) method for ochratoxin A using sequential phenyl silane and immunoaffinity column cleanup. The method was tested at 3 different levels of ochratoxin A in roasted coffee, which spanned the range of possible future European regulatory limits. The test portion was extracted with methanol and sodium bicarbonate by shaking for 30 min. The extract was filtered, centrifuged, and then cleaned up on a phenyl silane column before being eluted from the washed column with methanol–water. The eluate was diluted with phosphate-buffered saline (PBS) and applied to an ochratoxin A immunoaffinity column, which was washed with water. The ochratoxin A was eluted with methanol, the solvent was evaporated, and the residue was redissolved in injection solvent. After injection of this solution onto a reversed-phase LC apparatus, ochratoxin A was measured by fluorescence detection. Eight laboratory samples of low-level naturally contaminated roasted coffee and 2 laboratory samples of blank coffee (< 0.2 ng/g ochratoxin A at the signal-to-noise ratio of 3:1), along with ampules of ochratoxin A calibrant and spiking solutions, were sent to 15 laboratories in 13 different European countries. Test portions of the laboratory samples were spiked at levels of 4 ng/g ochratoxin A, and recoveries ranged from 65 to 97%. Based on results for spiked blank material (blind duplicates) and naturally contaminated material (blind duplicates at 3 levels), the relative standard deviation for repeatability (RSDr) ranged from 2 to 22% and the relative standard deviation for reproducibility (RSDR) ranged from 14 to 26%. The method showed acceptable within- and between-laboratory precision, as evidenced by HORRAT values, at the low level of determination for ochratoxin A in roasted coffee.

scholarly journals Determination of Ochratoxin A in Green Coffee by Immunoaffinity Column Cleanup and Liquid Chomatography: Collaborative Study

2005 ◽  
Vol 88 (3) ◽  
pp. 773-779 ◽  
Author(s):  
Eugênia Azevedo Vargas ◽  
Eliene Alves dos Santos ◽  
Alain Pittet ◽  
T B S Corrêa ◽  
A P P da Rocha ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Ochratoxin A ◽  
Relative Standard Deviation ◽  
Collaborative Study ◽  
Green Coffee ◽  
The European Union ◽  
Immunoaffinity Column ◽  
Test Portion ◽  
Relative Standard

Abstract A collaborative study was conducted to evaluate a method using immunoaffinity column cleanup with liquid chromatography (LC) for the determination of ochratoxin A (OTA) in green coffee at levels that could be included in possible future regulations of the European Union. The test portion was extracted with methanol–3% aqueous sodium hydrogen carbonate solution (50 + 50, v/v). The extract was filtered, and the filtrate was diluted with phosphate-buffered saline and applied to an immunoaffinity column containing antibodies specific for OTA. After washing, the toxin was eluted from the column with methanol and quantified by LC with fluorescence detection. Pairs of 4 homogeneous noncontaminated and naturally contaminated materials (mean levels of <0.12, 2.44, 5.15, and 13.46 ng/g) and blank samples (<0.12 ng/g) for spiking were sent to 20 participant laboratories from 8 countries. The materials were analyzed according to the method description and all difficulties encountered in the analysis were reported. Statistical analysis was carried out according to the Harmonized Protocol of the International Union of Pure and Applied Chemistry. The relative standard deviation for repeatability (RSDr) ranged from 7.42 to 20.94%, and the relative standard deviation for reproducibility (RSDR) ranged from 16.34 to 29.17%. The method showed acceptable within-laboratory and between-laboratories precision for green coffee materials, as evidenced by HorRat values of ≤0.85, at the studied range, for spiked and naturally contaminated materials. The mean recovery was 92.8% for green coffee material spiked with OTA at a level of 4.82 ng/g.

scholarly journals Liquid Chromatographic Determination of Ampicillin Residues in Porcine Muscle Tissue by a Multipenicillin Analytical Method: European Collaborative Study

2002 ◽  
Vol 85 (4) ◽  
pp. 889-900 ◽  
Author(s):  
Eric Verdon ◽  
Pierric Couëdor ◽  
Pierre Maris ◽  
Michel Laurentie ◽  
P Batjoens ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Muscle Tissue ◽  
Phosphate Buffer ◽  
Collaborative Study ◽  
Porcine Muscle ◽  
Relative Standard ◽  
Liquid Chromatographic

Abstract A collaborative study involving 14 laboratories was conducted to determine residues of ampicillin in porcine muscle tissue by using a liquid chromatographic method developed for multipenicillin analysis that can quantitate 8 penicillin compounds (benzylpenicillin, phenoxymethylpenicillin, ampicillin, amoxicillin, nafcillin, oxacillin, cloxacillin, and dicloxacillin) at trace levels in muscle tissue. This method involves extraction of the penicillins with phosphate buffer, pH 9, followed cleanup and concentration on a C18 solid-phase extraction column and reaction with benzoic anhydride at 50°C and with 1,2,4-triazole and mercury(II) chloride solution, pH 9.0, at 65°C. The derivatized compounds are eluted isocratically on a C8 column with a mobile phase of acetonitrile and phosphate buffer (pH 6; 0.1M) containing sodium thiosulfate and the ion-pair reagent tetrabutylammonium hydrogen sulfate. The penicillins are detected by UV absorption at 325 nm. The limit of detection and the limit of determination (quantitation) of the method were calculated to be approximately 3–5 and 25 μg/kg, respectively, in accordance with the criteria of European Union (EU) Decision No. 93/256/EEC. In this first interlaboratory study, collaborators were instructed to monitor 4 different penicillin compounds (benzylpenicillin, phenoxymethylpenicillin, ampicillin, and amoxicillin) by analyzing 8 blind samples of muscle tissue in triplicate. These samples were prepared from 2 materials containing different concentrations of incurred ampicillin (63.5 μg/kg for material No. 1 and 358.1 μg/kg for material No. 2) and 1 blank material. The repeatability relative standard deviation and the reproducibility relative standard deviation were 10.2 and 17.4%, respectively, for material No. 1 and 7.0 and 16.0%, respectively, for material No. 2. These results demonstrate that the method is suitable for the determination of ampicillin residues in muscle tissue at the EU maximum residue limit (50 μg/kg) and above. However, the identification of positives by this procedure may need additional confirmation by techniques with greater specificity, such as liquid chromatography combined with mass spectrometry, or tandem mass spectrometry. Investigations regarding the basis of interlaboratory testing studies will further demonstrate the suitability of multiresidue methodology for detecting and quantitating other compounds in the family of penicillin antibiotics.

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.

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.

Liquid Chromatographic Method for Determination of Explosives Residues in Soil: Collaborative Study

1990 ◽  
Vol 73 (4) ◽  
pp. 541-552 ◽  
Author(s):  
Christopher F Bauer ◽  
Stephan M Koza ◽  
Thomas F Jenkins
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Contaminated Soils ◽  
Chromatographic Method ◽  
Collaborative Study ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
Explosives Residues ◽  
Liquid Chromatographic

Abstract A collaborative study of a sonic extraction/liquid chromatographic method for determining nitroaromatic and nitramlne explosives In soil was conducted at 8 participating laboratories. Analytes HMX, RDX, TNB, DNB, tetryl, TNT, and 2,4-DNT were measured In duplicate for 4 field-contaminated soils and 4 spiked standard-matrix soils. Concentrations ranged from detection limits of about 1 μg/g to nearly 1000 μg/g. Results were evaluated with and without data Identified as outliers, which were often caused by electronic integrator miscalculation of chromatographic peak response. When outliers are excluded, method repeatability (within-laboratory relative standard deviation) for all analytes except tetryl Is less than 5% for spiked soils and less than 18% for fieldcontaminated soils. Relative standard deviation generally decreases as analyte concentration Increases. Reproducibility (between-laboratory relative standard deviation), except for tetryl and DNT, Is less than 7% for spiked soils and 26% for fleld-contamlnated soils. Thus, collaborators have nearly equivalent performance on spiked samples. For fleld-contamlnated soils, some additional Imprecision seems to result from the variability of extraction recoveries. Analyte recoveries from spiked soils are 95-97% for HMX, RDX, TNT, and DNT (similar to recoveries from aqueous samples); 92-93% for DNB and TNB; and 70% for tetryl. Poor results for tetryl (due to thermal degradation) are correctable If sonic bath temperatures are maintained near ambient. The method has been approved Interim official first action by AOAC.

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 Deoxynivalenol in Soft Wheat by Immunoaffinity Column Cleanup and LC-UV Detection: Interlaboratory Study

2009 ◽  
Vol 92 (1) ◽  
pp. 181-189 ◽  
Author(s):  
Gary Neumann ◽  
Gary A Lombaert ◽  
Susan Kotello ◽  
Nicole Fedorowich ◽  
E Abdelaal ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Uv Detection ◽  
Interlaboratory Study ◽  
Soft Wheat ◽  
Immunoaffinity Column ◽  
Cereal Products ◽  
Relative Standard ◽  
Liquid Chromatographic

Abstract An interlaboratory study was conducted to assess the applicability of a previously validated method for the analysis of deoxynivalenol (DON) in cereal and cereal products to soft wheat in the range of >0.13.0 g/g. The study evaluated a generic method to determine DON at levels that bracket the existing Canadian guidelines for DON in soft wheat destined for use in baby foods and nonstaple foods. Collaborators selected one of 2 approved brands of DON immunoaffinity column for cleanup and their choice of qualified C18 liquid chromatographic (LC) column. Separation was by LC with UV detection. Blind duplicates from 5 levels of naturally contaminated wheat and a pair of spiked wheat samples were successfully analyzed by 12 laboratories in 8 countries. For samples naturally contaminated with DON from <0.12.2 g/g, the relative standard deviation of repeatability (RSDr) ranged from 3.1 to 14.8. For reproducibility, the RSDR ranged from 21.0 to 32.9 and the HorRat range was 1.0 to 1.9. Recoveries of 0.5 g/g DON spiked into wheat ranged from 66 to 98, with an average of 84. The RSDr was 5.4, the RSDR was 12.6, and the HorRat value was 0.7.

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