Extraction and detection of mycotoxins in medicinal and aromatic plants: a case studywith Melissa officinalis L.
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 eo-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% NaHC03 (70:30, v/v)
[(OTA+AFs)2]; iii) maceration in methanol/1% NaHC03 (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 eoextraction
methods. For in-house validation of the selected methods OTA1
and AF1, recovery and precision were determined (n=6). The recovery of
OTA for metl:lod 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.
