Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XX
Written by Veronica DRUMEA, Roxana NITA, Lenuta ZGLIMBEA, Laura OLARIU
There are multiple ways in which pesticide contamination can take place, depending on the method used for obtaining the raw material: by conventional agriculture or harvest from wild flora. Assessing the transfer level of residues in extracts, in controlled conditions of preparation and analysis, contributes to determining the risk level for the consumer, as well as making processing choices that lead to a low concentration of contaminants. We used an adapted QuEChERS extraction method for liquid samples to compare the level of pesticides in plant extracts obtained by ethylic alcohol and acetone extraction. This was done by extraction in the presence of MgSO4 and NaCl and cleanup by dispersion with PSA, active charcoal and Mg SO4. To achieve the appropriate level of sensitivity, the injection module of the equipment was used in Programmed Temperature Vaporization (PTV) mode, injecting 3 μl of sample. Calibration was performed by the standard addition technique, in which case the correlations were linear. Our results show that ethylic alcohol extraction, commonly used for obtaining tinctures, leads to different residue transfer levels, depending on their chemical structure and solubility (between 15 and 76,8 % recovery, for quintozene and terbuthylazine respectively). On the other hand, acetone extraction is selective for pesticides, and the crystallization of the resulting bioactive compounds leads to significantly reduced pesticide levels.
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