Aura's "CUKE"s are made according to V. Sobolev and J. Dorner (1) and permit "a simple, fast, reliable, and inexpensive chemical cleanup procedure ... for quantitation of aflatoxins in major important agricultural commodities by liquid chromatography." An abbreviated description of the extraction and cleanup procedure is listed below. Consult this paper for details.  The reported procedure worked for the following commodities:Corn meal, Cottonseed, Peanuts, Almonds, English Walnuts, Brazil nuts and Pistachios.For quantitation Sobolev and Dorner (1) use the HPLC method with photochemical derivatization reported by Joshua (2). The post-column photochemical reactor, "PHRED", is also available from Aura Industries, Inc.

Price of AURA CUKEs:

• 1 package containing ten bags of ten CUKEs each (total 100) $ 195.00.

• 10 packages, each containing ten bags of ten CUKEs each, (total 1000) $ 1750.00.

1) V. Sobolev and J. Dorner, Cleanup Procedure for Determination of Aflatoxins in Major Agricultural Commodities by Liquid Chromatography, J. AOAC Int., 85, 642-645 (2002).

2) Henry Joshua, Determination of Aflatoxins by Reversed-Phase High Performance Liquid Chromatography with Post-Column Photochemical Derivatization and Fluorescence Detection, Journal of Chromatography, 654, 247-254 (1993).

Extraction and cleanup procedure:
Place 100gm of commodity in blender, add 200 ml of 80:20 methanol-water, and blend. Filter mix. To 0.5 ml of filtrate add 0.5 ml acetonitrile and mix. Dispense 0.5 ml of filtrate- acetonitrile mix into CUKE, no pressure or vacuum is required. Collect eluent and inject into HPLC.

"CUKE" Application Addendum
In an attempt to reconcile the potential for peak broadening due to a mismatch in the ratio of water:acetonitrile:methanol between the sample post-CUKE-preparation and the prescribed mobile phase for HPLC analysis (1), Aura’s scientists propose a cost effective amendment to the above procedure that improves the look and accuracy of resultant chromatograms.

Recommendations:
1) Decrease the sample injection volume from 20μL to 10μL 2) Use a mobile phase of water and methanol (65.2:34.8) and dispense with the need for the organic solvent 1-butanol. Sobolev and Dorner (1) propose a mobile phase of 65.3(water):1.2(1-butanol):33.6(methanol). We were able to dispense with the need for the organic solvent 1-butanol in the mobile phase and still had excellent peak shape with minimal peak broadening (Figure 1).

Figure 1. Chromatograms of aflatoxins G2, G1, B2, B1 retention times and sample injection volume shown on graph. (A, B, D, E) Aflatoxins prepared with CUKE solvent extraction ratio of 10:50:40 (water:acetonitrile:methanol) (C) Aflatoxins prepared with standard solvent extraction ratio of 63:22:15 (water:acetonitrile:methanol). (A, B, C) mobile phase 65.3:1.2:33.6 (water:1-butanol:methanol) (Sobolev and Dorner (1)) (D, E) mobile phase without 1-butanol, 65.2:34.8 (water:methanol)