Instrument settings, data acquisition and processing were controlled by the software Analyst (Version 1.5.1, Applied Biosystems). Source parameters were optimized as follows: ion spray voltage 4.5 kV for ESI (+), curtain gas 20 psi, collision gas 8 psi, nebulizer gas and auxiliary gas 30 psi and ion source temperature 500 C. Retention time, precursor ion, transitions, collision energy potentials (CE) and collision exit potentials (CXP) and optimal declustering potential (DP) of all studied analytes are shown in Table 1. Two SRM transitions were used for each analyte, one for quantification and other for qualification to avoid false negatives at trace pesticide levels.