A validated dispersive liquid-liquid microextraction method for extraction of ochratoxin A from raisin samples

Area of Science:

• Analytical Chemistry
• Food Safety

Background:

• Ochratoxin A (OTA) is a mycotoxin found in various food products, including raisins.
• Accurate quantification of OTA is crucial for ensuring food safety and compliance with regulatory limits.

Purpose of the Study:

• To develop and validate a dispersive liquid-liquid microextraction (DLLME) method for the quantitative analysis of Ochratoxin A (OTA) in raisin samples.
• To optimize DLLME parameters for efficient OTA extraction and compare the method with a standard immunoaffinity column chromatography (IAC) technique.

Main Methods:

• Dispersive liquid-liquid microextraction (DLLME) was employed for OTA extraction from raisin samples.
• Optimization of DLLME parameters including extractant type/volume, centrifuging/sonication time, and deionized water volume.
• Analysis of OTA using optimized DLLME followed by comparison with immunoaffinity Column Chromatography (IAC) for validation.

Main Results:

• Optimized DLLME achieved recovery rates between 68.6% and 85.2%.
• High precision was observed with relative standard deviation (RSD%) below 15% for inner and intra-day variability.
• The method demonstrated linearity from 0.5 to 30 μg/L, with LOD of 0.7 μg/kg and LOQ of 2.0 μg/kg.
• Real raisin samples showed a mean OTA contamination of 0.88 μg/kg, below the European legal limit.

Conclusions:

• The developed DLLME method is a cost-effective, rapid, and simple technique for OTA quantification in raisins.
• The method offers low organic solvent consumption and high efficiency, making it suitable for routine analysis.
• The DLLME method provides reliable results comparable to IAC, ensuring food safety compliance.