ABSTRACT
The determination of pesticides in food and environmental samples at low concentrations is always a challenge. Ideally, the analyte to be determined would be already in solution and at a concentration level high enough to be detected and quantified by the selected final determination technique (i.e., HPLC or GC). Unfortunately, the reality is far from this ideal situation. Firstly, the restrictive legislations from European Union and World Health Organization devoted to prevent contamination of food and environmental compartments by pesticides make necessary the development of analytical methods suitable for detecting target analytes at very low concentration levels. Besides, from a practical point of view, even when the analyte is already in solution (i.e., water or juice), there are several difficulties related to the required sensitivity and selectivity of the selected determination technique that must be overcome, since the concentration of matrix-interfering compounds is much higher than that of the analyte of interest. Consequently, the development of an appropriate sample preparation procedure involving extraction, enrichment, and cleanup steps becomes mandatory to obtain a final extract concentrated on target analytes and as free as possible of matrix compounds.
