scholarly journals Determination of Fumonisins B1 and B2 in Corn by LC/MS with Immunoaffinity Column Cleanup: Interlaboratory Study

2010 ◽  
Vol 93 (2) ◽  
pp. 611-621 ◽  
Author(s):  
Hamide Z Senyuva ◽  
John Gilbert ◽  
Joerg Stroka ◽  
S Biselli ◽  
A De Girolamo ◽  
...  
Keyword(s):  
Fine Powder ◽  
Immunoaffinity Column ◽  
Selected Ion Monitoring ◽  
Test Portion ◽  
Method Performance ◽  
Three Samples ◽  
Interlaboratory Validation ◽  
Cleanup Procedure ◽  
Phosphate Buffered Saline

Abstract An interlaboratory validation study was conducted to establish the method performance characteristics of an immunoaffinity column (IAC) cleanup procedure followed by LC/MS for the determination of fumonisins B1 (FB1) and B2 (FB2) and combined FB1 + FB2 in corn. The test portion is extracted with acetonitrilemethanolwater (25 + 25 + 50). The extract is filtered, diluted with phosphate-buffered saline solution, and applied to an IAC. FB1 and FB2 are removed with methanol, followed by water, then directly determined by RPLC with MS detection using selected-ion monitoring of two characteristic ions in each case. Naturally contaminated corn samples were milled to a fine powder and mixed to produce three samples with target levels of combined FB1 + FB2 ranging from 350 to 4000 g/kg. Of 15 initially participating laboratories, two failed to report results and another did not follow the prescribed method. Thus, valid results were obtained from 12 participants located in 11 countries. Statistical analysis of the results produced RSDr values of 4.611.9, 1.912.6, and 1.411.5 for FB1, FB2, and combined FB1 + FB2, respectively; the corresponding RSDR values were 19.823.8, 18.225.5, and 18.823.2. The three concentration levels of combined FB1 + FB2 were 534, 1194, and 1954 g/kg. HorRat values for r and R were all <2.0, indicating that the method is suitable as a regulatory method for the enforcement of European Union limits for fumonisins in corn.

Immunoaffinity Column Cleanup with LC/MS/MS for the Determination of Chloramphenicol in Honey and Prawns: Single-Laboratory Validation

2013 ◽  
Vol 96 (4) ◽  
pp. 910-916 ◽  
Author(s):  
Jennifer Mackie ◽  
Elaine Marley ◽  
Carold Donnelly
Keyword(s):  
Immunoaffinity Column ◽  
Buffer Solution ◽  
Method Performance ◽  
Wide Range ◽  
Negative Ionization Mode ◽  
Cleanup Procedure ◽  
Seafood Products ◽  
Negative Ionization ◽  
Single Laboratory

Abstract A single-laboratory validation was conducted to establish the effectiveness of an immunoaffinity column (IAC) cleanup procedure followed by LC/MS/MS for the determination of chloramphenicol (CAP) in honey and prawns. Honey is dissolved in buffer solution and centrifuged, and an aliquot applied to an IAC. For prawns, a portion of the homogenized sample is shaken with buffer and centrifuged, and an aliquot similarly applied to an IAC. For both matrix extracts, CAP is removed from the IAC with neat methanol, then directly analyzed by electrospray LC/MS/MS in the negative ionization mode using m/z 321 as a precursor ion and m/z 257 and 152 as qualifier and quantifier ions, respectively. Test portions of blank honey and prawns were fortified with CAP to give levels of 0.3, 1.0, and 5.0 μg/kg. Recoveries of CAP on 3 consecutive days ranged from 83–103% for honey and 84–108% for prawns. Based on results for fortified blank matrixes (triplicate at three levels), the RSD for repeatability (RSDr) averaged 8.4% for honey and 4.8% for prawns. The method LOD was 0.05 for prawns and 0.16 μg/kg for honey, both well below the minimum required method performance limit for CAP. The accuracy of the method was demonstrated by participation in proficiency testing, where satisfactory Z-scores were obtained for CAP in incurred samples of both honey and prawns. The method was shown to be applicable to a wide range of other matrixes, including milk, egg, royal jelly, meat, and seafood products.

scholarly journals Immunoaffinity Column Cleanup with Liquid Chromatography Using Post-Column Bromination for Determination of Aflatoxins in Hazelnut Paste: Interlaboratory Study

2005 ◽  
Vol 88 (2) ◽  
pp. 526-535 ◽  
Author(s):  
Hamide Z Senyuva ◽  
John Gilbert
Keyword(s):  
Liquid Chromatography ◽  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Aflatoxin B1 ◽  
The United States ◽  
Interlaboratory Study ◽  
Immunoaffinity Column ◽  
Test Portion ◽  
Relative Standard

Abstract An interlaboratory study was conducted to evaluate the effectiveness of an immunoaffinity column cleanup liquid chromatography (LC) method for determination of aflatoxin B1 and total aflatoxins in hazelnut paste at European regulatory limits. The test portion was extracted with methanol–water (6 + 4). The extract was filtered, diluted with phosphate-buffered saline (PBS) solution to a specified solvent concentration, and applied to an immunoaffinity column containing antibodies specific to aflatoxins. The aflatoxins were removed from the immunoaffinity column with methanol, and then quantified by reversed-phase LC with post-column derivatization (PCD) involving bromination. The PCD was achieved with electrochemically generated bromine (Kobra Cell®) followed by fluorescence detection (except for one participant who used pyridinum hydrobromide perbromide for bromination). Hazelnut paste, both naturally contaminated with aflatoxins and blank (<0.1 ng/g) for spiking by participants with aflatoxins, was sent to 14 collaborators in Belgium, The Netherlands, Spain, Turkey, the United Kingdom, and the United States. Test portions were spiked at levels of 4.0 and 10.0 ng/g for total aflatoxins by participants using supplied total aflatoxins standards. Recoveries for total aflatoxins and aflatoxin B1 averaged from 86 to 89%. Based on results for naturally contaminated samples (blind duplicates at 3 levels ranging from 4.0 to 11.8 ng/g total aflatoxins), the relative standard deviation for repeatability (RSDr) ranged from 2.3 to 3.4% for total aflatoxins and from 2.2 to 3.2% for aflatoxin B1. The relative standard deviation for reproducibility (RSDR) ranged from 6.1 to 7.0% for total aflatoxins and from 7.3 to 7.8% for aflatoxin B1. The method showed exceptionally good within-laboratory and between-laboratory precision for hazelnut paste, as evidenced by HORRAT values, which in all cases were significantly below target levels, the low levels of determination for both aflatoxin B1 and total aflatoxins.

scholarly journals Occurrence of aflatoxins in peanuts and peanut products determined by liquid chromatography with fluorescence detection

2013 ◽  
pp. 27-35 ◽  
Author(s):  
Biljana Stojanovska-Dimzoska ◽  
Zehra Hajrulai-Musliu ◽  
Elizabeta Dimitrieska-Stojkovic ◽  
Risto Uzunov ◽  
Pavle Sekulovski
Keyword(s):  
Liquid Chromatography ◽  
Fluorescence Detection ◽  
Limit Of Detection ◽  
Total Content ◽  
Immunoaffinity Column ◽  
Limit Of Quantification ◽  
Three Samples ◽  
The Mean ◽  
Positive Results

Liquid chromatography with fluorescence detection using immunoaffinity column clean-up was a method described for determination of aflatoxins (AFB1, AFB2, AFG1 and AFG2) in peanuts and peanut based products. The validation of the procedure was performed. Good coefficient of correlation was found for all aflatoxins in the range of 0.9993-0.9999. Limit of detection (LOD) and limit of quantification (LOQ) ranged from 0.003-0.005 mg/kg and 0.009-0.023 mg/kg, respectively, which was acceptable. The mean recovery for total aflatoxins was 88.21%. The method also showed acceptable precision values in the range of 0.171-2.626% at proposed concentration levels for all four aflatoxins. RSDR values (within laboratory reproducibility) calculated from the results showed good correlation between two analysts for all aflatoxins and they ranged from 4.93-11.87%. The developed method was applied for the determination of aflatoxins in 27 samples of peanuts and peanut based products. The results showed that 21 peanut samples (77.7%) were below LOD of the method. Three samples had positive results over the MRL. There was one extreme value recorded for the total aflatoxins in peanut (289.2 mg/kg) and two peanut based products, peanut snack and peanut, with total content of aflatoxins being 16.3 mg/kg and 8.0 mg/kg, respectively. The obtained results demonstrated that the procedure was suitable for the de?termination of aflatoxins in peanuts and peanut based products and it could be implemented for the routine analysis.

Determination of Clenbuterol in Cattle, Sheep, and Swine Tissues by Electron Ionization Gas Chromatography/Mass Spectrometry

1994 ◽  
Vol 77 (4) ◽  
pp. 917-924 ◽  
Author(s):  
Roger T Wilson ◽  
Joseph M Groneck ◽  
Kathleen P Holland ◽  
A Carolyn Henry
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Internal Standard ◽  
Electron Ionization ◽  
Gas Chromatography Mass Spectrometry ◽  
Selected Ion Monitoring ◽  
Method Performance ◽  
Chromatography Mass Spectrometry ◽  
Coefficients Of Variation

Abstract A gas chromatographic/mass spectrometric procedure is described for the quantitation and confirmation of clenbuterol residues from cattle, sheep, and swine tissues. After liquid–liquid extraction and derivatization with phosgene in an aqueous pH 10.1 buffer, the cyclic oxazolidone derivative is quantitated with a clenbuterol analogue as internal standard (NAB-760 CI). Confirmation is accomplished by comparison of ion ratios with those of a pure synthesized standard of clenbuterol oxazolidin-3-one obtained by selected ion monitoring, electron ionization gas chromatography/mass spectrometry on a benchtop instrument. Statistical information based on a series of standard curves for fortified tissues is included to describe method performance. Ion ratio variations were under 15%, and coefficients of variation for spiked tissue standard curves were above 0.997. Recoveries averaged 87.1 ± 6.6% for liver tissues across all 3 species and 67.1 ± 3.8% for muscle tissue across all 3 species.

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.

Determination of Aflatoxins and Ochratoxin A in Traditional Turkish Cereal-Based Fermented Food by Multi-Affinity Column Cleanup and LC Fluorescence Detection: Single-Laboratory Validation

2019 ◽  
Vol 102 (1) ◽  
pp. 156-163 ◽  
Author(s):  
Tugrul Kaymak ◽  
Ercan Koca ◽  
Mustafa Atak ◽  
Ercan Sarikaya ◽  
Joerg Stroka
Keyword(s):  
Ochratoxin A ◽  
Fluorescence Detection ◽  
Performance Criteria ◽  
Immunoaffinity Column ◽  
Method Performance ◽  
Column Method ◽  
Relative Standard ◽  
Varied Composition ◽  
Single Laboratory

Abstract Background: Tarhana is a traditional fermented, sun-dried Turkish food containing yogurt and cereals. There are several potential sources of mycotoxins in tarhana, such as contamination of ingredients or formation during preparation, when water activity is suitable for fungal growth and may lead to mycotoxin production during fermentation or subsequent sun-drying. Objective: To optimize an immunoaffinity column method and carry out single-laboratory validation for the determination of aflatoxins B1, B2, G1, and G2 together with ochratoxin A (OTA) in tarhana. Method: A homogenized sample was extracted with methanol–acetonitrile–water (25 + 25 + 50) using a high-speed blender. The sample extract was filtered, diluted with phosphate buffered saline (PBS) solution, and applied to a multi-immunoaffinity column (AFLAOCHRA PREP®). Aflatoxins and OTA were removed with neat methanol and then directly analyzed by reverse-phase LC with fluorescence detection using post-column bromination (Kobra® Cell). Results: Test portions of blank tarhana were spiked with a mixture of total aflatoxins and OTA to give levels ranging from 2.5 to 10.0 and 1.5 to 6.0 μg/kg, respectively. Recoveries for total aflatoxins and OTA ranged from 82 to 93 and 78 to 94%, respectively, for spiked samples. Based on results for spiked tarhana (30 replicates, each at three levels), the relative standard deviation for repeatability ranged from 1.4 to 7.2 and 3.6 to 7.7% for total aflatoxins and OTA, respectively. Conclusions: The performance characteristics for recovery, repeatability, and sensitivity have demonstrated that the method meets method performance criteria for use for official purposes. The method was demonstrated as being applicable to naturally contaminated samples of tarhana of varied composition obtained from local markets in Turkey. Highlights: This is the first immunoaffinity column method for simultaneous analysis of aflatoxins and OTA in traditional Turkish food (tarhana). Suitability was demonstrated by single-laboratory validation for official purposes in Turkey. The method was demonstrated as suitable for naturally contaminated samples of tarhana of varied composition.

Evaluation and interlaboratory validation of a GC-MS method for analysis of pesticide residues in teas

2007 ◽  
Vol 61 (1) ◽  
pp. 1-5 ◽  
Author(s):  
C. Peng ◽  
H. Kuang ◽  
X. Li ◽  
C. Xu
Keyword(s):  
Simultaneous Determination ◽  
Pesticide Residues ◽  
Graphitized Carbon Black ◽  
Gas Chromatography Mass Spectrometry ◽  
Selected Ion Monitoring ◽  
External Standard Method ◽  
Relative Standard ◽  
Interlaboratory Validation ◽  
Acetone Hexane

AbstractA method was described for simultaneous determination of nine organic heterocyclic pesticide residues by gas chromatography-mass spectrometry-selected ion monitoring. Atrazine, vinclozolin, procymidone, triflumizole, imazalil, buprofezin, propiconazole, fenarimol, and pyridaben were clearly separated from each other, extracted with acetone—hexane mixture, purified with graphitized carbon black cartridge and neutral Al2O3 cartridge, eluted with acetone—hexane mixture, simultaneously determined by GC-MS, and then quantified with an external standard method. Recoveries of pesticides ranged from 73 % to 116 % at the spiked level of 0.01–30 mg kg−1, while the relative standard deviation was between 3 % and 27 %. In addition, the limits of determination (0.01 mg kg−1 to 5.0 mg kg−1) and linearity (0.02–40 μg mL−1) revealed that simultaneous determination of multi-residues in Chinese teas (like Oolong tea, green tea, red tea, etc.) was possible. Furthermore, an interlaboratory study among 5 labs was conducted to further validate the method, and the results were satisfactory.

Determination of Vitamin B12 in Infant Formula and Adult Nutritionals Using HPLC After Purification on an Immunoaffinity Column: First Action 2011.09

2012 ◽  
Vol 95 (4) ◽  
pp. 933-936 ◽  
Author(s):  
Ursula Kirchner ◽  
Katharina Degenhardt ◽  
Guenther Raffler ◽  
Maria Nelson
Keyword(s):  
Vitamin B12 ◽  
Measurement Uncertainty ◽  
Infant Formula ◽  
Potassium Cyanide ◽  
Immunoaffinity Column ◽  
Validation Data ◽  
Method Performance ◽  
Expert Review ◽  
Wide Range

Abstract During the “Standards Development and International Harmonization: AOAC INTERNATIONAL Mid-Year Meeting,” on June 29, 2011, the method “Determination of Vitamin B12 in Infant Formula and Adult Nutritionals Using HPLC After Purification on an Immunoaffinity Column” was recommended by an Expert Review Panel and adopted as AOAC Official First Action status. The method is applicable for the determination of vitamin B12 in milk-based infant formula. Vitamin B12 is extracted from the sample in sodium acetate buffer in the presence of potassium cyanide. After purification and concentration with an immunoaffinity column (IAC), vitamin B12 is determined by LC with UV detection (361 nm). Data supplied by CLF demonstrated linear response over a wide range of concentrations (1.4–39 μg/100 mL). The analytical range is 0.2–10 μg/100 g, depending on the capacity of the IACs (0.01–0.5 μg), the input weight, and dilutions. Recovery rates were assessed using National Institute of Standards and Technology SRM 1849, and determined to be 95.1%, with SD of 0.34 and CV of 9.0. Measurement uncertainty (UE) was 0.8 μg/100 g, which was calculated from the validation data. It is an expanded measurement uncertainty and was obtained through multiplication with a coverage factor k. LOQ values were reported as 0.10 μg/100 g. The performance characteristics of the method met the standard method performance requirements set forth by the AOAC Stakeholder Panel on Infant Formula and Adult Nutritionals; thus, the method was determined to be appropriate for First Action status.

scholarly journals Determination of Fumonisins B1 and B2 in Corn-Based Foods for Infants and Young Children by LC with Immunoaffinity Column Cleanup: Interlaboratory Validation Study

2011 ◽  
Vol 94 (3) ◽  
pp. 900-908 ◽  
Author(s):  
Michele Solfrizzo ◽  
Annalisa De Girolamo ◽  
Lucia Gambacorta ◽  
Angelo Visconti ◽  
Joerg Stroka ◽  
...  
Keyword(s):  
Young Children ◽  
Validation Study ◽  
Food Samples ◽  
Precolumn Derivatization ◽  
Immunoaffinity Column ◽  
Mass Fractions ◽  
Interlaboratory Validation ◽  
Liquid Chromatographic ◽  
Infants And Young Children

Abstract A liquid chromatographic method for the determination of fumonisins B1 (FB1) and B2 (FB2) in corn-based foods for infants and young children was subjected to an interlaboratory validation study involving 11 laboratories. Five blind duplicate sample pairs of each matrix were analyzed to establish the accuracy, repeatability, and reproducibility of the method. Mass fractions in the baby food samples ranged from 89.1 to 384.4 μg/kg FB1 and from 22.5 to 73.6 μg/kg FB2. The method involved a warm extraction with citrate phosphate buffer–methanol–acetonitrile (50 + 25 + 25, v/v/v), a cleanup through an immunoaffinity column, and an end-determination of fumonisins by LC after automated precolumn derivatization with-o-phthaldialdehyde reagent. RSDs for within- laboratory repeatability (RSDr) ranged from 6.8 to 23.5% for FB1 and 7.6 to 22.9% for FB2. RSDs for between-laboratory reproducibility (RSDR) ranged from 15.4 to 26.2% for FB1 and 21.6 to 36.3% for FB2. Mean FB1 recoveries from baby foods spiked at 100.0 and 250.0 μg/kg were 89 and 96%, respectively; for FB2 spiked foods at 25.0 and 62.5 μg/kg recoveries were 90 and 85%, respectively. HorRat values ranged from 0.8 to 1.2 for FB1, whereas for FB2 they ranged from 0.9 to 1.4 when calculated according to Horwitz, and from 1.0 to 1.7 when calculated according to Thompson, indicating an acceptable among- laboratory precision for all matrixes (HorRat values <2).

Liquid Chromatographic Determination of Aflatoxin Levels in Peanut Butters Using an Immunoaffinity Column Cleanup Method: International Collaborative Trial

1991 ◽  
Vol 74 (1) ◽  
pp. 76-81 ◽  
Author(s):  
Alan L Patey ◽  
Matthew Sharman ◽  
John Gilbert
Keyword(s):  
Peanut Butter ◽  
Chromatographic Determination ◽  
Immunoaffinity Column ◽  
Collaborative Trial ◽  
Coefficients Of Variation ◽  
Relative Standard ◽  
Cleanup Procedure ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract Thirteen laboratories In 7 different countries participated in a collaborative trial to evaluate an Immunoaffinity column cleanup procedure with quantitation by fluorescence liquid chromatography (post-column derivatization) for the determination of aflatoxins In peanut butters. Participants were sent 10 randomly numbered samples of roasted peanut butter for analysis (5 pairs of undisclosed duplicates). Two of the pairs were "blank" peanut butters to which aflatoxin standards had been added; these "spiked" samples were used for recovery purposes. The other 3 pairs of samples were a nominal "blank" and 2 naturally contaminated peanut butters. A full statistical presentation of the results is given. Coefficients of variation (CVs) for the total aflatoxin determinations for mean levels of 4,15, and 38 µ/kg were between 32 and 44% for the blank and 2 trial samples. Recovery levels for the 2 spiked samples were 51-67%, with aflatoxin B1 recovery of 60%. Relative standard deviations for method repeatability (RSDr) and reproducibility (RSDR) for the 3 trial samples were 15-26% and 33-45%, respectively.

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