Resumen de Development of analytical methodologies for multiresidue pesticide analysis in agri-food products from colombia
Diana Angélica Varela Martínez
Colombia has experienced in recent years a strong growth in the production and export of agri-food products. The country harvests a wide variety of agricultural products as a result of its privileged geographic location, climatic conditions, thermal floors and hydrographic basins. Colombia is unique for the food that it grows and produces for exportation around the world.
Agriculture has an important role in the Colombian economy. It is indeed the second generator of direct and indirect jobs and, for this reason, an increasing number of farmers know that they need to develop strategies to make their crops more productive and competitive in the global markets to meet the current worldwide demand. In this sense, the use of pesticides in modern agriculture is still high due to the advantages it brings in terms of quality and quantity of products. However, the intensive use of pesticides has awoken a special concern due to the risks and effects that they are causing to human life with its consumption and exposure, especially, when the most vulnerable population of the society is at risk.
The presence of pesticide residues in food matrices is of great interest nowadays, since it is important to ensure their safe consumption. In particular, it is necessary to identify and quantify pesticide residues, being a challenge for researchers to find and to suitably validate analytical methods that encompass different classes of analytes and agri-food matrices in a single analysis. At the same time, the extraction capacity of such methods should be efficient enough to comply with quantification at trace levels as indicated by current legislation, which is increasing its restrictions. In this sense, the QuEChERS method is one of the procedures most widely applied nowadays as a pesticide multiresidue method in food products. QuEChERS offers clear advantages for the obtaining of precise results, high recoveries, a simple and rapid treatment, reduced use of solvents and reagents, and requires the use of few laboratory materials and space to carry out sample preparation. It is also possible to treat several samples at a time, which increases its throughput. The method uses different reagents that have several purposes: reducing the water content of the extracts, facilitating the analysis of analytes sensitive to alkaline pH, promoting the effective extraction of the analytes to the organic phase, eliminating matrix components (pigments, lipids, sugars, etc.) that interfere/difficult the analysis and preserving the correct performance chromatographic and mass spectrometry systems.
With all the above considerations, the main objective of this PhD Thesis is to develop, validate, and apply “classical” and new versions of the QuEChERS method using GC-MS/MS for the determination of a wide range of pesticides residues in agri-food products of Colombia, especially, in minor tropical fruits, since they have hardly been applied to many of them.
The AOAC 2007.01 and QuEChERS versions of ammonium formate provided better performance in terms of lower coextraction materials, matrix effects, extraction efficiency and precision than the original and CEN 15662 methods. In particular, the application of the CEN 15662 version. Ammonium formate is clearly advantageous from different points of view (it does not contaminate the detection system and increases the ionization of analytes) and should be studied and applied properly, whenever possible.
The application of the developed methodologies were applied to the analysis of 77 real samples. These data indicate that, regarding the selected pesticides, their consumption is safe, although there are still other pesticides that could be analyzed, in particular the non-volatile ones, for which LC-MS / MS is required.
