Rafael López-Blanco1, David Moreno-González1, Rocío Nortes-Méndez1, Juan F.
García-Reyes1, Antonio Molina-Díaz1,2 and Bienvenida Gilbert-López1*
1Analytical Chemistry Research Group, Department of Physical and Analytical Chemistry, University of Jaén, Campus Las Lagunillas, Edif. B-3, 23071 Jaén, Spain.
E-mail: [email protected]
2Center for Advanced Studies in Olives Grove and Olive Oils (CEAOAO) Science and Technology park GEOLIT, E-23620 Mengíbar, Jaén (Spain)
The establishment of Maximum Residue Levels (MRLs) of pesticides in raw and processed food is a policy necessary to ensure food safety and thus, to protect consumer health. However, although the procedure to set MRLs in raw food is standardized, the definition of MRLs in processed food is often a matter of discussion. In Europe, a decade after EU regulation 396/2005 became into force, annex VI on MRLs in processed food remains unpublished. Considering this scenario, the purpose of the present work was the experimental evaluation of processing factors of a large set of representative pesticides applied in olive orchards worldwide. The ultimate goal is to understand their behavior during olive oil production and predict their processing factors, which could be eventually used for the calculation of MRLs in olive oil from the MRLs set in olives. A laboratory-scale Abencor system was used for the production of olive oil from olives spiked with the 104 pesticides studied, being three different chromatographic methods used for the analysis of raw olives and the obtained olive oil: (i) gas chromatography tandem mass spectrometry (GC- MS/MS) for GC-amenable pesticides; (ii) hydrophilic interaction liquid chromatography tandem mass spectrometry (HILIC-MS/MS) for polar pesticides, and; (iii) reversed phase liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) for low to medium polarity pesticides. The behavior of the pesticides during olive oil extraction was plotted against their polarity using Kow values, finding a linear relation between the processing factors experimentally calculated and their octanol water partitioning coefficient (log Kow). With this relation set, the processing factors of new pesticides could be estimated and, additionally, an accurate estimation of the actual concentration of pesticides transferred from olives to olive oil could be also made, enabling the calculation of the equivalent MRLs in olive oil from the MRLs in olives, considering the percentage of oil extracted (oil yield) and the log Kow of each pesticide.
Acknowledgements
The authors acknowledge funding support from Regional Government of Andalusia (Spain) “Junta de Andalucía” (Research Group FQM-323 and Project Ref. AGR-6182). Technical support provided by Dr. Juan Castro-Marmol from CICT (Centro de Instrumentación Científico-Técnica) of the University of Jaén is gratefully acknowledged. D.M.G. thanks the Spanish Ministerio de Economía y Competitividad (MINECO) for a Juan de la Cierva Formación postdoctoral contract (ref. FJCI-2014–19573).
PO-AL-14
EVALUATION OF A MODIFIED QuEChERS METHOD FOR THE MONITORING OF MYCOTOXIN RESIDUES IN NUTS BY NANO FLOW LC-HRMS
David Moreno-González,MiriamBeneito-Cambra, Bienvenida Gilbert López, Juan F. García-Reyes and Antonio Molina-Díaz
Analytical Chemistry Research Group, Department of Physical and Analytical Chemistry, University of Jaén, 23071, Jaén, Spain. E-mail: [email protected]
Mycotoxins are toxic secondary metabolites produced by a wide range of fungi growing on many agricultural commodities and processed food. Their presence in food could show mutagenic, teratogenic, carcinogenic, and immunosuppressive effects in animals and humans. In fact, several organizations including European Union have regulated the levels of mycotoxins in crops such as nut, cereal, corn, milk, and edible oils. For instance, the maximum residue level for aflatoxin B1 in peanut is 8 µg kg-1. Thus, the development of analytical methods, which can determine mycotoxin residues in these types of matrices at very low concentrations, has acquired significant relevance across the globe. Nano flow liquid chromatography coupled with electrospray tandem MS can be an interesting alternative to conventional LC methodologies, since it provides significant benefits in terms of sensitivity and matrix effect reduction. In this work, a new analytical method based on nanoflow liquid chromatography high resolution mass spectrometry is proposed for the identification and simultaneous quantification of a representative group of mycotoxins in nut samples. Detection was undertaken with a Thermo Q-Exactive Orbitrap mass spectrometer equipped with an Easy-Spray nano-electrospray ion source. For the separation of the studied analytes, a Thermo Scientific EASY-nLC 1000 nano-LC system was used. An EASY-Spray column (PepMap®, C18, 3 µm, 100Å, 75 µm x 150 mm) was employed. Mobile phases A and B were water and acetonitrile, respectively, both with 0.1 % formic acid. The injection volume was 1 µL. Flow rate was set at 300 nL·min-1. Another aspect of paramount interest for the determination of mycotoxin in nut samples is the sample treatment. It is not an easy task due to the high lipid composition of this type of samples, requiring sample treatments with exhaustive clean-up. QuEChERS methodology has been proposed as a straightforward alternative for extraction and clean-up. Moreover, a new sorbent, Enhanced Matrix Removal-Lipid (EMR-Lipid) has been tested for dispersive solid phase extraction (dSPE), after extraction of mycotoxin with acetonitrile. Preliminary studies have yielded promising results in terms of matrix effect, sensitivity and recovery, obtaining negligible matrix effects for all mycotoxins studied in peanut, pistachio and almond. Thus, nano flow LC-HRMS combined with a modified QuEChERS based on the use EMR-Lipid could be used as a, convenient and high throughput method for clean-up and analysis of mycotoxin in nut samples at trace concentrations.
Acknowledgements
The authors acknowledge, funding support from Ministerio de Economía y Competitividad (MINECO) (Ref. CTQ-2015- 71321-P). D.M.G. thanks the Spanish Ministerio de Economía y Competitividad (MINECO) for a Juan de la Cierva Formación postdoctoral contract (ref. FJCI-2014–19573).
PO-AL-15
DETERMINATION OF TROPANE ALKALOIDS IN CEREAL-BASED FOODS