Mixed-mode sorption of hydroxylated atrazine degradation products to sell: A mechanism for bound residue
Environmental Science & Technology
By: R.N. Lerch, E.M. Thurman, and E.L. Kruger
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Abstract
This study tested the hypothesis that sorption of hydroxylated atrazine degradation products (HADPs: hydroxyatrazine, HA; deethylhydroxyatrazine, DEHA; and deisopropylhydroxyatrazine, DIHA) to soils occurs by mixed-mode binding resulting from two simultaneous mechanisms: (1) cation exchange and (2) hydrophobic interaction. The objective was to use liquid chromatography and soil extraction experiments to show that mixed-mode binding is the mechanism controlling HADP sorption to soils and is also a mechanism for bound residue. Overall, HADP binding to solid-phase extraction (SPE) sorbents occurred in the order: cation exchange >> octadecyl (C18) >> cyanopropyl. Binding to cation exchange SPE and to a high-performance liquid chromatograph octyl (C8) column showed evidence for mixed-mode binding. Comparison of soil extracted by 0.5 M KH2P04, pH 7.5, or 25% aqueous CH3CN showed that, for HA and DIHA, cation exchange was a more important binding mechanism to soils than hydrophobic interaction. Based on differences between several extractants, the extent of HADP mixed-mode binding to soil occurred in the following order: HA > DIHA > DEHA. Mixed-mode extraction recovered 42.8% of bound atrazine residues from aged soil, and 88% of this fraction was identified as HADPs. Thus, a significant portion of bound atrazine residues in soils is sorbed by the mixed-mode binding mechanisms.
Suggested Citation
Lerch, R., Thurman, E., Kruger, E., 1997, Mixed-mode sorption of hydroxylated atrazine degradation products to sell: A mechanism for bound residue: Environmental Science & Technology, v. 31, no. 5, p. 1539-1546, https://doi.org/10.1021/es960811w.
ISSN: 1520-5851 (online)
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | Mixed-mode sorption of hydroxylated atrazine degradation products to sell: A mechanism for bound residue |
| Series title | Environmental Science & Technology |
| DOI | 10.1021/es960811w |
| Volume | 31 |
| Issue | 5 |
| Publication Date | April 29, 1997 |
| Year Published | 1997 |
| Language | English |
| Publisher | ACS |
| Contributing office(s) | Toxic Substances Hydrology Program |
| Description | 8 p. |
| First page | 1539 |
| Last page | 1546 |