Photodegradation of the herbicide imazethapyr in aqueous solution: Effects of wavelength, pH, and natural organic matter (NOM) and analysis of photoproducts

Ryan Espy; Emily Pelton; Annie Opseth; Jonathan Kasprisin; Amanda M. Nienow

doi:10.1021/jf200573g

Photodegradation of the herbicide imazethapyr in aqueous solution: Effects of wavelength, pH, and natural organic matter (NOM) and analysis of photoproducts

Ryan Espy, Emily Pelton, Annie Opseth, Jonathan Kasprisin, Amanda M. Nienow

Chemistry (Twin Cities)

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35 Scopus citations

Abstract

The photodegradation of imazethapyr, 5-ethyl-2-(4-isopropyl-4-methyl-5-oxo- 4,5-dihydroimidazol-1H-3-yl)nicotinic acid, has been investigated in phosphate buffers and in buffered solutions containing natural organic matter (NOM). Imazethapyr degrades most quickly under 253.7 nm light and at pH values >4. The presence of NOM in solution caused the reaction rate constants for the photodegradation to decrease, with higher concentrations of NOM having a larger effect. Calculations suggest light screening is the major effect of the NOM. Seven photoproducts have been identified, and a photodegradation mechanism is proposed.

Original language	English (US)
Pages (from-to)	7277-7285
Number of pages	9
Journal	Journal of agricultural and food chemistry
Volume	59
Issue number	13
DOIs	https://doi.org/10.1021/jf200573g
State	Published - Jul 13 2011

Keywords

imazethapyr
imidazolinone
natural organic matter
photodegradation
photolysis
photoproducts

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title = "Photodegradation of the herbicide imazethapyr in aqueous solution: Effects of wavelength, pH, and natural organic matter (NOM) and analysis of photoproducts",

abstract = "The photodegradation of imazethapyr, 5-ethyl-2-(4-isopropyl-4-methyl-5-oxo- 4,5-dihydroimidazol-1H-3-yl)nicotinic acid, has been investigated in phosphate buffers and in buffered solutions containing natural organic matter (NOM). Imazethapyr degrades most quickly under 253.7 nm light and at pH values >4. The presence of NOM in solution caused the reaction rate constants for the photodegradation to decrease, with higher concentrations of NOM having a larger effect. Calculations suggest light screening is the major effect of the NOM. Seven photoproducts have been identified, and a photodegradation mechanism is proposed.",

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author = "Ryan Espy and Emily Pelton and Annie Opseth and Jonathan Kasprisin and Nienow, {Amanda M.}",

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T2 - Effects of wavelength, pH, and natural organic matter (NOM) and analysis of photoproducts

AU - Espy, Ryan

AU - Pelton, Emily

AU - Opseth, Annie

AU - Kasprisin, Jonathan

AU - Nienow, Amanda M.

PY - 2011/7/13

Y1 - 2011/7/13

N2 - The photodegradation of imazethapyr, 5-ethyl-2-(4-isopropyl-4-methyl-5-oxo- 4,5-dihydroimidazol-1H-3-yl)nicotinic acid, has been investigated in phosphate buffers and in buffered solutions containing natural organic matter (NOM). Imazethapyr degrades most quickly under 253.7 nm light and at pH values >4. The presence of NOM in solution caused the reaction rate constants for the photodegradation to decrease, with higher concentrations of NOM having a larger effect. Calculations suggest light screening is the major effect of the NOM. Seven photoproducts have been identified, and a photodegradation mechanism is proposed.

AB - The photodegradation of imazethapyr, 5-ethyl-2-(4-isopropyl-4-methyl-5-oxo- 4,5-dihydroimidazol-1H-3-yl)nicotinic acid, has been investigated in phosphate buffers and in buffered solutions containing natural organic matter (NOM). Imazethapyr degrades most quickly under 253.7 nm light and at pH values >4. The presence of NOM in solution caused the reaction rate constants for the photodegradation to decrease, with higher concentrations of NOM having a larger effect. Calculations suggest light screening is the major effect of the NOM. Seven photoproducts have been identified, and a photodegradation mechanism is proposed.

KW - imazethapyr

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KW - photolysis

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Photodegradation of the herbicide imazethapyr in aqueous solution: Effects of wavelength, pH, and natural organic matter (NOM) and analysis of photoproducts

Abstract

Keywords

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