The MS system was set in selective ion monitoring (SIM) mode
and each compound was quantified based on the peak area using
three qualifier ions (Table 1). Identification and confirmation of
pesticides were performed as recommended by the European
SANCO Guidelines [24].
The optimized injector temperature was 250 1C. The GC oven
temperature program was 80 1C, followed by a 50 1C min−1 ramp
to 160 1C (held for 1 min), then by a 2 1C min−1 ramp to 180 1C and
a final ramp of 160 1C min−1 to 360 1C (held for 4 min). A solvent
delay time of 7.0 min was set to prevent instrument damage. The
MS was calibrated with perfluorotributylamine (PFTBA). The MS
system temperature of the detector interface was set at 280 1C and
the source of ionization at 250 1C.