2.5.1. GC-NPD and GC-ECD systems Fungicides were separated and determined in a Hewlett Packard model 6890 Gas Chromatography system fitted with NP and EC-detector and with a DB-608 (30 m x 0.53 mm i d.) col- uman for EC-detector and a BPX-5 (30 m x 0.32 mm i d.) column for NP-detector and equipped with a Chemstation chromatog raphy manager data acquisition and processing system. The gas chromatograph oven temperature program started from 60 oC for 1.5 min, increased to 220 C with a rate of 14 oC/min, held for 4 min and then increased to 280 C (with 20 C/min) and held for 20 min. The carrier gas (helium) flow rate was 5 mL/min for DB-608 and 1.5 mL/min for BPX-5 columns; injector tem perature was at 230 oC and the splitless injection was carried out with purge valve on at 1 min. Hydrogen (3 mL/min) and air (60 mL/min) were used as fuel gases for the NPD, while nitro- gen (60 ml/min) and helium (6 mL/min) were used as auxiliary gases for the ECD. Both detectors temperature was at 310 C.