The use of ethyl acetate associated with acetonitrile provided less colorful (yellow) extracts, making the clean-up step easier. The use of sodium acetate together with acetic acid buffered the extracts (pKa of acetic acid = 4.75) improving pesticides stability and increasing the extraction efficiency. Magnesium sulfate was used in order to ensure dryness of the sample by means of an exothermic reaction, leading to phase separation and extraction of the compounds by the acetonitrile:ethyl acetate solution. To remove the matrix interference, a clean-up step was
also performed. A dispersive solid phase extraction employing PSA together with Florisil was performed. PSA had the ability to retain matrix components, such as polar organic acids, sugars and fatty acids. Florisil improved sample clean-up, due to the sugars interaction with the polar surface of this sorbent (Koesukwiwat, Sanguankaew, & Leepipatpiboon, 2008; Kujawski et al., 2014; Prestes et al., 2009).