Quantitative Analysis of Aflatoxin in Edible Nuts by Using High-Performance Liquid Chromatography Coupled with Florescence Detector

Introduction

Aflatoxins are toxic metabolites produced by molds such as Aspergillus flavus and Aspergillus parasiticus. These fungi can contaminate nuts when conditions like high humidity and warm temperatures occur during cultivation, drying, storage, or transport. Nuts including peanuts, almonds, pistachios, cashews, walnuts, and Brazil nuts are particularly susceptible. Even low levels of contamination can pose serious health risks. Early detection and control of aflatoxin contamination help prevent economic losses and safeguard consumers from long-term toxic effects. Reliable and sensitive detection of B₁, B₂, G₁, and G₂ aflatoxins in nut products is therefore critical, particularly in view of the strict limits set by the European Union (e.g., a maximum of 2 µg/kg for aflatoxin B_₁ and 4 µg/kg for total aflatoxins in nuts intended for direct human consumption). The analysis commonly begins with immunoaffinity cartridges, which selectively capture aflatoxins while removing other matrix components. This step not only concentrates the toxins but also reduces interference, enhancing the accuracy and reproducibility of subsequent measurements. For detection, post-column photochemical derivatisation is employed to increase the natural fluorescence of aflatoxin B₁ and G₁, improving sensitivity and lowering detection limits. This derivatisation method is rapid, reagent-free, and well-suited for routine monitoring of aflatoxins in complex food samples.

January 21, 2026 GMT