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Title:   Author  item
                                            Schmidt, Walteritem
                                            Hapeman, Cathleenitem
                                            Rice, Clifforditem
                                            McConnell, Laura
  Submitted to: Meeting Abstract
                                    Publication Type: Abstract Only
                                    Publication Acceptance Date: 7/1/2014
                                    Publication  Date: 8/10/2014
                                    Citation: Schmidt, W.F., Hapeman, C.J., Rice, C., Mcconnell, L.L. 2014. Discerning the flexibility and rigidity of beta-endosulfan isomerization to alpha-endosulfan using temperature-dependent Raman (TDR) spectroscopy: Influences on environmental fate [abstract]. American Chemical Society. AGRO 479.Interpretive Summary:
                                Technical Abstract: Endosulfan has been identified as a persistent organic pollutant (POP) due to its persistence, bioaccumulation, long-range transport, and adverse effects to human health and aquatic ecosystems. Phased-out in the United States will occur in 2016. Endosulfan consists of two diastereomers, alpha and beta. Alpha-Endosulfan exists as two asymmetrical, twist-chair enantiomers which interchange, while beta-endosulfan has a symmetrical-chair conformation. Beta-Endosulfan has been shown to isomerize to alpha-endosulfan. Previously-proposed isomerization mechanism was re-examined using temperature-dependent Raman (TDR) spectroscopy. The bending frequencies in the fingerprint region were assigned to specific bonds. Changes in the signal intensity as a function of temperature were used to identify detailed ring movements, and thus conversion of beta to alpha. These movements cannot occur simultaneously nor symmetrically, precluding conversion of alpha-endosulfan to beta-endosulfan. Furthermore, this mechanism explains the overwhelming presence of alpha-endosulfan in air samples.


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