Abstract :
[en] Ever since their discovery in the 1960s, aflatoxins have presented a significant public health concern and posed a difficult challenge for ensuring food quality control. The fact that these carcinogenic substances are found in various food sources like nuts, maize, rice, and dairy products has prompted authorities to establish maximum allowable levels for these contaminants in these specific goods. Given the moderately polar nature of these compounds, official methods rely on employing methanol/water or acetonitrile/water solutions as extraction solvents. Moreover, since the contamination levels can vary within a batch, a considerable amount of both the sample and the extraction solvent is needed for analysis, resulting in a substantial amount of waste generated during the process. Additionally, samples of pistachios, complex and rich in lipids and other interfering compounds, require a crucial sample preparation step before analysis. To address these challenges, a novel technique utilizing deep eutectic solvents (DES) as extraction solvents is proposed. DES belongs to a new category of environmentally friendly solvents that involve combining a hydrogen bonding donor and acceptor in the right molar ratio, resulting in a clear solution with a significantly lower melting point than its individual constituents. Most DESs have demonstrated non-toxic and biodegradable properties, along with excellent extraction capabilities for various target compounds. Given the complex nature of the extract obtained from aflatoxin-contaminated pistachios, an additional purification and concentration step was necessary. The DES extracts were diluted with water and passed through a C18 solid-phase extraction (SPE) cartridge, where the trapped aflatoxins were subsequently eluted using a minimal amount of methanol and injected into an HPLD-FLD instrument equipped with a partially porous C18 column. The mobile phase consisted of a gradient elution system using methanol and water, ranging from 30% to 60% MeOH over a period of 7.5 minutes. The flow rate was set at 0.45 mL/min, the injection volume at 2 µL, and the column temperature maintained at 35°C. This approach demonstrated the viability of using DES as extraction solvents for such a complex sample matrix, thereby reducing the reliance on organic solvents and minimizing process waste.
