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Aflatoxins B/G and Ochratoxin A in Pistachios



Whether salty, as ice cream, as pistachio paste or as noble decoration on pralines - we encounter pistachios in the most varied forms. The stone fruit belongs to the sumac family. Already in classical antiquity, it was appreciated as a delicacy, in the Roman Empire it was even used as a remedy.

The origin of pistachios is not known, but Iran, the USA and Turkey are among the largest growing areas. The fruit consists for the most part of unsaturated fatty acids and has a large proportion of B vitamins. Pistachios are particularly susceptible to the development of mycotoxins as they provide a good basis for the growth of moulds whose metabolites can have toxic effects. 

Drying or incorrect storage conditions promote the indication of mycotoxins. Therefore, a too high proportion of mycotoxins may be toxic to humans. For this reason, the European Union carries out strict import controls. If the mycotoxin content is too high, they are returned to the country of origin.

Combined Analysis of Ochratoxin A and Aflatoxin B/G

Aflatoxin B/G and ochratoxin A are often found together in many food and feed products. To facilitate the extraction of the two mycotoxins, LCTech developed the Alfa-OtaCLEAN columns for combined clean-up. The Afla-OtaCLEAN columns are available in the useful 3 mL format. Additional, LCTech offers miniaturized SMART columns. You can put the immunoaffinity columns AflaCLEAN SMART and OtaCLEAN SMART on top of each other and clean-up aflatoxins B/G and ochratoxins A in one step. 

On the following page, you will find a processing protocoll for the use of 3 mL Afla-OtaCLEAN columns as well as AflaCLEAN SMART or OtaCLEAN SMART columns.

Processing Protocol

Homogenise 20 g of pistachios with 100 mL methanol/ water (80/20 (v/v)). To ensure high extraction efficiencies, continue the extraction by using an Ultra-Turrax 3 - 5 minutes or by using a magnetic stirrer for 10 - 20 minutes. Filtrate the raw extract and dilute 7 mL of the n-hexane free phase with 43 mL PBS. Filtrate the diluted extract through a Whatman glass fiber filter to remove turbidities.

Stick the AlfaCLEAN SMART column over the Male/Female-Luer connector onto the OtaCLEAN SMART column. The columns can be combined pressure-tight by the special connection. Load 10 mL sample (corresponds to 0.28 g matrix) with a maximum flow rate of 1.5 mL/min onto the column. Flush the sample container with 2 mL of deionized water and load the rinsing solution also onto the column.

Elute the AflaCLEAN SMART and OtaCLEAN SMART column with 400 ┬ÁL of methanol. The elution of both columns at the same time is possible, as long as the analysis provides for simultaneous measurement of the two toxin groups. Keep in mind that the eluent is applied to the column bed for at least 5 minutes before collecting the eluate. Dry the column with a short airflow and collect any remaining eluate.

Alfa-OtaCLEAN column:
Load 50 mL of the sample onto the 3 mL Afla-OtaCLEAN column (corresponds to1.4 g matrix). Rinse the sample container with 10 mL of deionized water and load the rinsing solution onto the column. Dry the column bed with a short airflow and elute the toxins with 2 mL methanol. Make sure that the methanol incubates in the column bed for 5 minutes to ensure a fully denaturation of the antibodies and release of the toxin.

Compared to the 3 mL Afla-OtaCLEAN column, the AflaCLEAN SMART and OtaCLEAN SMART column give you a smaller volume. However, the concentration remains the same. This not only saves solvents, but also money and time.

Find more details, recovery rates, HPLC-conditions and chromatograms here.

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