We noted an irreversible adsorption of these compounds to the sample container surface; for this reason,all glassware used in this study was extensively cleaned using solvents in sequence, such as water, methanol, dichloromethane and then again methanol. Also frits and SPE cartridges were precleanedby sonication with methanol into an ultrasonic bath twice for 10 min each. Moreover, all solvents utilized were carefully checked to be analyte-free, performing blank procedure analysis. We noted solvent contaminations so that all organic solvents were redistilledin glass apparatus before use (see Section 3).