EFFECT OF BOILING AND SOME ENVIRONMENTAL

FACTORS ON RESIDUES BEHAVIOUR OF PENCONAZOLE FUNGICIDE ON VINE LEAVES

[27]

Nasr¹, I.N.; Nevein S. Ahmed¹ and M.M. Al-Maz¹

ABSTRACT

A sensitive and reliable GLC method has been adapted for the determination of penconazole residues in vine leaves, grapes and under certain environmental conditions using electron capture detector (ECD). The recoveries of penconazole were 70 – 96 % .The limits of determination of the method were 0.005 and 0 .01 mg /kg for leaves and grapes respectively. The method was applied to determine residues and rate of disappearance of penconazole from leaves and under effect of  temperatures, UV-rays and directs sunlight. The fungicide incorporated into vine leaves decreased rapidly with a half –life of less than 3 days. According to the codex maximum residue limits of 0.02 ppm, vine leaves could be used safely for human consumption after 5 days from field treatment. No penconazole residues detected in grapes picked up at marketing time after 120 days from field application. The percentage loss of penconazole residues from treated vine leaves boiled in water from three minutes were 53.55, 55.12 and 52.81% after 0, one and 3 days after field treatment. The exposure of direct sunlight on penconazole residues suffered greatly deterioration within 12 hours compared to those exposed to UV – rays. Hence, the calculated half- lives values were 2.7 and 18 hours for penconazole when exposed to direct sunlight and UV-rays respectively. While the half-lives values were 140, 38, 31 and 13 hours when exposed to different temperatures of 25, 35, 40 and 45ºC respectively.