Extraction and detection of mycotoxins in medicinal and aromatic plants: a case study with Aloysia citrodora P.
Conference Paper
Overview
Overview
abstract
Plants frequently suffer contaminations by toxigenic fungi, and their mycotoxins can be produced
throughout growth, harvest, drying and storage periods. The objective of this work
was to validate a method for detection of toxins in medicinal and aromatic plants, through a
fast and highly sensitive method, optimizing the joint co-extraction of aflatoxins (AF: AFB1,
AFB2, AFG1 and AFG2) and ochratoxin A (OTA) by using Aloysia citrodora P. (lemon verbena)
as a case study. For optimization purposes, samples were spiked (n=3) with standard
solutions of a mix of the four AFs and OTA at 10 ng/g for AFB1, AFG1 and OTA, and at 6
ng/g of AFB2 and AFG2. Several extraction procedures were tested: i) ultrasound-assisted
extraction in sodium chloride and methanol/water (80:20, v/v) [(OTA+AFs)1]; ii) maceration
in methanol/1% NaHCO3 (70:30, v/v) [(OTA+AFs)2]; iii) maceration in methanol/1% NaHCO3
(70:30, v/v) (OTA1); and iv) maceration in sodium chloride and methanol/water (80:20, v/v) (AF1). AF and OTA were purified using the mycotoxin-specific immunoaffinity columns
AflaTest WB and OchraTest WB (VICAM), respectively. Separation was performed with a
Merck Chromolith Performance C18 column (100 x 4.6 mm) by reverse-phase HPLC coupled
to a fluorescence detector (FLD) and a photochemical derivatization system (for AF). The
recoveries obtained from the spiked samples showed that the single-extraction methods
(OTA1 and AF1) performed better than co-extraction methods. For in-house validation of
the selected methods OTA1 and AF1, recovery and precision were determined (n=6). The
recovery of OTA for method OTA1 was 81%, and intermediate precision (RSDint) was 1.1%.
The recoveries of AFB1, AFB2, AFG1 and AFG2 ranged from 64% to 110% for method AF1,
with RSDint lower than 5%. Methods OTA1 and AF1 showed precision and recoveries within
the legislated values and were found to be suitable for the extraction of OTA and AF for the
matrix under study.
