The Malaysian Journal of Analytical Sciences, Vol 14 No 1 (2010): 50 – 55
HYDROLYSIS OF CHLORPYRIFOS IN AQUEOUS SOLUTIONS AT
DIFFERENT TEMPERATURES AND pH
Tay Joo Hui1,2, Marinah Mohd Ariffin1,
Norhayati Mohd Tahir1*
1Environmental
Research Group (ERG),
Department of Chemical Sciences, Faculty
of Science and Technology,
Universiti
2Faculty of
Industrial Sciences and Technology (FIST),
Universiti Malaysia Pahang (UMP),
Lebuhraya Tun Razak,
26300 Gambang, Kuantan, Pahang Darul
Makmur, Malaysia.
*Corresponding author: hayati@umt.edu.my
Abstract
The
hydrolysis of chlorpyrifos (O,O-diethyl-O-3,5,6-trichloro-2-pyridyl
phosphorothionate) was investigated in buffered aqueous media at different
temperature and pH conditions. Rate
constants and half-life studies revealed that chlorpyrifos was relatively
stable in acidic medium. The rate of
degradation increased as the pH increased.
Temperature showed a significant effect on the rate of hydrolysis. The hydrolysis of chlorpyrifos in water
follows first-order kinetics. The
half-life of chlorpyrifos in aqueous solutions was short (half-lives ranged
from
Keywords: Chlorpyrifos, hydrolysis,
organophosphorus pesticide.
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