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231225s2021 xx |||||o 00| ||eng c |
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|a 10.1002/mrc.4935
|2 doi
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|a pubmed25n1001.xml
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|a eng
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|a Whitty, Stephanie D
|e verfasserin
|4 aut
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|a Direct noninvasive 1 H NMR analysis of stream water DOM
|b Insights into the effects of lyophilization compared with whole water
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|c 2021
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|a Text
|b txt
|2 rdacontent
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|a ƒaComputermedien
|b c
|2 rdamedia
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|a ƒa Online-Ressource
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|2 rdacarrier
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|a Date Completed 24.05.2021
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|a Date Revised 24.05.2021
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|a published: Print-Electronic
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|a Citation Status PubMed-not-MEDLINE
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|a © 2019 John Wiley & Sons, Ltd.
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|a NMR spectroscopy is widely used in the field of aquatic biogeochemistry to examine the chemical structure of dissolved organic matter (DOM). Most aquatic DOM analyzed by proton NMR (1 H NMR) is concentrated mainly by freeze-drying prior to analysis to combat low concentrations, frequently <100 μM C, and eliminate interference from water. This study examines stream water with low dissolved organic carbon content by 1 H NMR with a direct noninvasive analysis of whole water using a water-suppression technique. Surface waters, collected from the headwaters of the Rio Tempisquito, Costa Rica, were examined directly, and the spectral characteristics were compared with those of the traditional preanalysis freeze-drying approach revealing significant differences in the relative intensity of peaks between the whole water and freeze-dried DOM. The freeze-dried DOM required less time to obtain quality spectra, but several peaks were missing compared with the spectra of whole water DOM; notably the most dominant peak in the spectrum constituting roughly 10% of the DOM. The stream water DOM showed an increase in the relative intensity of aliphatic methyl and methylene groups and a decrease in carbonyl, carboxyl, and carbohydrate functionalities after freeze-drying. The results of this study show that freeze-drying alters the original composition of DOM and thus freeze-dried DOM may not represent the original DOM. The information gained from whole water analysis of stream water DOM in a noninvasive fashion outweighs the attraction of reduced analysis times for preconcentrated samples, particularly for studies interested in investigating the low molecular weight fraction of DOM
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|a Journal Article
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|a Research Support, U.S. Gov't, Non-P.H.S.
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|a dissolved organic matter
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|a freeze-dried DOM
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|a headwater streams
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|a lyophilization
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|a proton NMR
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|a stream water DOM
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| 650 |
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4 |
|a whole water analysis
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| 700 |
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|a Waggoner, Derek C
|e verfasserin
|4 aut
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| 700 |
1 |
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|a Cory, Rose M
|e verfasserin
|4 aut
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| 700 |
1 |
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|a Kaplan, Louis A
|e verfasserin
|4 aut
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| 700 |
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|a Hatcher, Patrick G
|e verfasserin
|4 aut
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| 773 |
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|i Enthalten in
|t Magnetic resonance in chemistry : MRC
|d 1985
|g 59(2021), 5 vom: 05. Mai, Seite 540-553
|w (DE-627)NLM098179667
|x 1097-458X
|7 nnns
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| 773 |
1 |
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|g volume:59
|g year:2021
|g number:5
|g day:05
|g month:05
|g pages:540-553
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|u http://dx.doi.org/10.1002/mrc.4935
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