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
Email: schalk@unf.edu
Website: @unf

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Vegetable

Classification: Vegetable -> peanut

Citations 3

"Fluorimetric Determination Of Aflatoxins By Flow Injection Analysis"
Fresenius J. Anal. Chem. 1988 Volume 332, Issue 7 Pages 809-812
Fernando Lazaro, M. Dolores Luque de Castro and Miguel Valcarcel

Abstract: Peanuts (100 g) are extracted by shaking with 500 mL of aqueous 55% methanol plus 200 mL of hexane and 4 g of NaCl. A 25 mL portion of the aqueous methanol phase is extracted with 25 mL of CHCl3, the CHCl3 is evaporated under N, and the residue is dissolved in 5 mL of methanol. The solution is diluted to 10 mL with water, filtered through nylon 66 (0.45 µm) and extracted with 10 mL of CHCl3. The extract is evaporated, the residue is dissolved in 1 mL of methanol, and the solution is diluted to 5 mL with water. Maize or tapioca (50 g) is mixed with 10 g of diatomaceous earth and extracted with 150 mL of aqueous 85% acetone, the mixture is filtered, and 50 mL of the filtrate is mixed with 20 mL of saturated (NH4)2SO4 solution, 130 mL of water and 10 g of diatomaceous earth. This mixture is filtered, and 100 mL of the filtrate is extracted with 3 mL of benzene. The extract is evaporated under N, the residue is dissolved in methanol and the solution diluted with water as before. Each sample solution was injected into a stream of aqueous 40 µM-Br, and the fluorescence was monitored at 470 nm. From 0.5 to 200 ng mL-1 of total aflatoxins (B1, B2, G1 and G2) could be determined. The method is very rapid, the residence time for each flow injection peak being only 6 s.
Aflatoxins Fluorescence

"Fluorimetric Determination Of Aflatoxins In Foodstuffs By High Performance Liquid Chromatography With Flow Injection Analysis"
J. Chromatogr. A 1988 Volume 448, Issue 1 Pages 173-181
F. Lázaro, M. D. Luque de Castro and M. Valcárcel

Abstract: Aflatoxins were extracted from peanuts and maize (methods given). Portions of the extract were injected in to a column (20 cm x 4 mm) of Nucleosil 120 (5 µm) for HPLC with a mobile phase (0.7 mL min-1) of water - methanol - acetonitrile (94:59:47) and fluorimetric detection at 440 nm (excitation at 360 nm) after flow injection derivatization of aflatoxins B1 and G1 with Br. Calibration graphs were rectilinear from 0.5 to 200 ng mL-1 of aflatoxins G2, G1, B2 and B1. The coefficient of variation (n = 11) were 1.7, 1.0, 1.7 and 1.8%, respectively.
Aflatoxin B1 Aflatoxin B2 Aflatoxin G1 Aflatoxin G2 HPLC Fluorescence Merging zones Optimization 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