Peanut butter is an invention of Dr. John Harvey Kellogg from the 19th century, who also invented the cornflakes at that time. He pureed peanuts in order to obtain a nutritious food for patients without teeth. Today about half of the peanut harvest of the USA goes into the production of peanut butter. As this is still not enough, further tons of nuts and finished products are imported. Despite the high calorie content (90 calories per tablespoon!), peanut butter is healthy: it contains plenty of vitamin E and H and its also a very good energy supplier. In the USA it is used as a classic bread spread, but also peanut butter biscuits, brownies or cakes are very popular.
However, for the import of food and feed, there are strict EU-wide-regulations for the permissible content of mycotoxins. Thus, an effective and significant analysis is essential. In 2016 alone, 177 exceedances of the limits for aflatoxins B/G in peanuts were found followed by the consequence of an import ban. [Source: RASFF-Portal]
Automated Preparation with FREESTYLE SPE
The number of SPE methods is virtually innumerable. The individual method requirements couldn`t be more different. Yet almost all methods can be automated using the FREESTYLE SPE - without compromise.
Protocol of Processing
Homogenise 20 g of peanut butter and add 2 g of sodium chloride. Extract the sample with 100 mL methanol/water (80/20 (v/v)) and 50 mL of n-hexane in order to remove fat and oils. The extraction should be conducted for 20 - 30 minutes.
Centrifuge the extract for the phase separation between the aqueous and the n-hexane phase with 2000 x g for 10 minutes. Dilute 10.5 mL of the aqueous (lower) phase with 64.5 mL PBS-buffer. In case of precipitations filtrate the sample with a glass fiber filter.
Load the extract onto a AflaCLEAN immunoaffinity column. Wash the sample reservoir afterwards with 2 x 5 mL deionised water and load this solution also onto the IAC-column.
Dry the column and elute it with 2 mL methanol. Keep in mind, that the methanol incubates for 5 minutes into the column bed, in order to dissolve the antibody toxin bond completely. Dilute the sample to HPLC conditions and measure it afterwards.