Effects of Relative Humidity on
Chloroacetanilide and Dinitroaniline
Herbicide Desorption from
Agricultural PM<sub>2.5</sub> on Quartz Fiber
Filters
Wenli Yang
Britt A. Holmén
10.1021/es062692i.s002
https://acs.figshare.com/articles/journal_contribution/Effects_of_Relative_Humidity_on_Chloroacetanilide_and_Dinitroaniline_Herbicide_Desorption_from_Agricultural_PM_sub_2_5_sub_on_Quartz_Fiber_Filters/3004030
This study quantified the release of seven relatively polar
preemergence herbicides to the gas phase from soil-generated PM<sub>2.5</sub>-loaded quartz fiber filters (QFFs) and bare
QFF as a function of relative humidity (RH). A 48-hour
desorption fraction, <i>F</i><sub>48</sub>, was defined to evaluate the relative
desorption behavior of herbicides from two families,
chloroacetanilide (alachlor, butachlor, metolachlor, and
propachlor) and dinitroaniline (pendimethalin, prodiamine,
and trifluralin) using temperature- (8 °C) and humidity- (10−64% RH) controlled air at a flow rate of 4 L/min. With increasing
RH, an increase in <i>F</i><sub>48</sub> by a factor of 2−8 was observed
for all herbicides, except metolachlor and butachlor, which
showed significantly strong sorption to both sorbents.
The conjugate carbonyl oxygen and amide nitrogen in the
chloroacetanilide structure enables stronger specific
interactions with the sorbents, leading to lower desorption
compared to the dinitroaniline herbicides. Desorption of
chloroacetanilides decreased in the order propachlor >
alachlor > metolachlor ∼ butachlor, and desorption of
dinitroanilines decreased in the order trifluralin >
pendimethalin > prodiamine. These orders are consistent
with the different substituents in the herbicide molecules
for each family and their relative tendencies to coordinate
with surface moieties as indicated by electron-donating
capacity. Henry's law constant and Abraham's H-acceptor
parameter were found to be useful empirical parameters
for describing the <i>F</i><sub>48</sub> desorption behavior for all seven
herbicides.
2007-06-01 00:00:00
Relative Humidity
RH
desorption behavior
dinitroaniline herbicides
Quartz Fiber FiltersThis study
F 48
amide nitrogen
metolachlor
gas phase
butachlor
conjugate carbonyl oxygen
flow rate
order trifluralin
F 48 desorption behavior
QFF
order propachlor
Agricultural PM 2.5
herbicide molecules
Dinitroaniline Herbicide Desorption
surface moieties
chloroacetanilide structure
preemergence herbicides