University of North Florida
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Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Website: @unf

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Classification: Food -> peanut butter

Citations 5

"Robotic Automation In The Analysis Of Aflatoxins"
Adv. Lab. Autom. Rob. 1991 Volume 7, Issue 1 Pages 303-313
Pieta, L.

Abstract: Peanut butter (25 g) was blended with 125 mL of aqueous 60% methanol for 1 min, the mixture was filtered and a 10 mL portion of the filtrate was mixed with 10 mL of water. The resulting solution was placed in a tube in the sample rack of a Zymate Master Laboratory Station. The system automatically carried out affinity chromatography on an Aflatest-P column with acetone as eluent, evaporation of the eluate under N and reconstitution of the residue in aqueous 23% THF. The solution was then automatically subjected to HPLC on a column of Radial-Pak Phenyl (5 µm), operated at 30°C, with aqueous 23% THF as mobile phase (1.2 mL min-1), post-column derivatization with iodine at 75°C and fluorimetric detection at 400 nm (excitation at 360 nm). The robotic procedure afforded better reproducibility than the corresponding manual procedure. Recoveries were >91%. Samples throughput was 40 day-1.
Aflatoxins HPLC Fluorescence Automation Filtration Heated reaction Post-column derivatization Robot

"Liquid Chromatographic Determination Of Aflatoxin Levels In Peanut Butters Using An Immunoaffinity Column Cleanup Method: International Collaborative Trial"
J. AOAC Int. 1991 Volume 74, Issue 1 Pages 76-81
Patey AL, Sharman M, Gilbert J.

Abstract: The preliminary collaborative trial of the Biocode Total Aflatoxin Easi-Extract immunoaffinity column (Biocode, York, UK) reported previously (Food Addit. Contam., 1990, 7, 515) has been followed by a formal inter-laboratory study. Each participating laboratory received 15 Biocode columns, 10 samples of roasted peanut butter, an analysis protocol and the stipulation that LC with post-column-derivatization fluorimetric detection be used for determination. Recoveries for spiked samples were 51 to 67%. The coefficient of variation for repeatability and reproducibility were 15 to 26% and 33 to 45%, respectively; overall coefficient of variation for 4, 15 and 38 µg kg-1 of total aflatoxin were 32 to 44%.
Aflatoxins LC Fluorescence Post-column derivatization

"Immunoaffinity Column Coupled With Solution Fluorimetry Or Liquid Chromatography Post-column Derivatization For Determination Of Aflatoxins In Corn [maize], Peanuts And Peanut Butter: Collaborative Study"
J. AOAC Int. 1991 Volume 74, Issue 1 Pages 81-88
Trucksess MW, Stack ME, Nesheim S, Page SW, Albert RH, Hansen TJ, Donahue KF.

Abstract: The preliminary evaluation of the Aflatest P immunoaffinity column (Vicam, Somerville, MA) reported previously (Ibid., 1990, 73, 425) has been followed by an AOAC - IUPAC collaborative study. Each participating laboratory received samples of naturally contaminated maize and of maize, peanuts and peanut butter containing added aflatoxins (30, 20 and 10 ng g-1, respectively). Total aflatoxins were determined by fluorimetry in solution with Br; individual aflatoxins by reversed-phase LC with post-column derivatization with I. For total aflatoxins, recoveries were 105 to 123% and coefficient of variation for repeatability and reproducibility were 11.8 to 16.6 and 11.0 to 33.1%, respectively. For individual aflatoxins, the corresponding ranges were 81 to 83, 5.2 to 17.2 and 4.7 to 50.8%. Use of immunoaffinity columns with either method of determination is recommended as official first action.
Aflatoxins LC Fluorescence Post-column derivatization

"Aflatoxin Analysis By Reversed-phase HPLC Using Post-column Derivatization For Enhancement Of Fluorescence"
J. Liq. Chromatogr. Relat. Technol. 1986 Volume 9, Issue 1 Pages 103-112
P. G. Thiel; S. Stockenstrom; P. S. Gathercole

Abstract: Aflatoxins extracted from maize, peanut butter, sorghum malt or duckling mash were subjected to HPLC on a column (7.5 cm x 4.6 mm) of Altex Ultrasphere ODS (3 µm) with a mobile phase (1 mL min-1) of 0.01 M KH2PO4 - acetonitrile - methanol (39:9:7); the eluate was treated with saturated aqueous iodine at 60°C before the fluorescence was measured at 440 nm (excitation at 365 nm). The calibration graphs were rectilinear for 1.16, 0.48, 1.48 and 0.84 ng µL-1 for aflatoxins B1, B2, G1 and G2, respectively.
Aflatoxin B1 Aflatoxin B2 Aflatoxin G1 Aflatoxin G2 HPLC Fluorescence Heated reaction Post-column derivatization

"Liquid Chromatographic Analysis Of Thiamine And Its Phosphates In Food Products Using Amprolium As An Internal Standard"
J. Micronutr. Anal. 1986 Volume 2, Issue 3 Pages 189-199
Huang, M. H.A.

Abstract: Samples of food (e.g., pork, chicken, ham, bread, cereal, almonds or peanut butter) were blended (if necessary) and mixed with 5% sulfosalicylic acid solution and amprolium (internal standard). The mixture was extracted with hexane, and the extract was cleaned-up on a column (30 cm x 6 mm) of Bio-Rad AG 2-X8 anion-exchange resin with elution by using 0.1 M sodium phosphate buffer (pH 5.5). The eluate was analyzed by HPLC on a column (3 cm x 3 mm) of C18 material (3 µm) with a mobile phase (1 mL min-1) of two 0.1 M sodium phosphate buffers (pH 5.5 and 2.6) for 6 min and 19 min, respectively. Fluorimetric detection was at 432 nm (excitation at 339 nm) after post-column derivatization of thiamine and its phosphates to their thiochrome derivatives.
Thiamine Thiamine monophosphate HPLC Fluorescence Post-column derivatization