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Title: Organic Enrichment at Aqueous Interfaces: Cooperative Adsorption of Glucuronic Acid to DPPC Monolayers Studied with Vibrational Sum Frequency Generation

Abstract

Surface tension, surface-specific vibrational spectroscopy and differential scanning calorimetry measurements were all used to test cooperative adsorption of glucuronic acid (GU) to DPPC monolayers adsorbed to the aqueous/vapor interface. Experiments were performed using GU solutions prepared in Millipore water and in carbonate/bicarbonate solutions buffered to a pH of 9.0. The effects of GU on DPPC monolayer structure and organization were carried out with tightly packed monolayers (40 Å2/DPPC) and monolayers in their liquid condensed phase (55 Å2/molecule). Surface tension data show that GU concentrations of 50 mM lead to expanded DPPC monolayers with diminished surface tensions (or higher surface pressures) at a given DPPC coverage relative to monolayers on pure water. With unbuffered solutions, GU induces significant ordering within liquid condensed monolayers although the effects of GU on tightly packed DPPC monolayers are less pronounced. GU also induces a second, higher melting temperature in DPPC vesicles implying that GU (at sufficiently high concentrations) strengthens lipid-lipid cohesion, possibly by replacing water solvating the DPPC headgroups. Together, these observations all support a cooperative adsorption mechanism. In buffer solutions, the effects of dissolved GU on DPPC structure and organization are muted. Only at sufficiently high GU concentrations (when the solution’s buffering capacity hasmore » been exceeded) do the data again show evidence of cooperative adsorption. These findings place limits on cooperative adsorption’s ability to enrich interfacial organic content in alkaline environmental systems such as oceans.« less

Authors:
 [1];  [2]; ORCiD logo [3];  [3]; ORCiD logo [3]; ORCiD logo [4];  [2]
  1. MONTANA STATE UNIVERSITY
  2. Montana State University
  3. BATTELLE (PACIFIC NW LAB)
  4. VISITORS
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1571276
Report Number(s):
PNNL-SA-144535
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry A
Additional Journal Information:
Journal Volume: 123; Journal Issue: 26
Country of Publication:
United States
Language:
English

Citation Formats

Link, Katie A., Spurzem, Gabrielle, Tuladhar, Aashish, Jessamy-Chase, Zizwe A., Wang, Zheming, Wang, Hongfei, and Walker, Robert A. Organic Enrichment at Aqueous Interfaces: Cooperative Adsorption of Glucuronic Acid to DPPC Monolayers Studied with Vibrational Sum Frequency Generation. United States: N. p., 2019. Web. doi:10.1021/acs.jpca.9b02255.
Link, Katie A., Spurzem, Gabrielle, Tuladhar, Aashish, Jessamy-Chase, Zizwe A., Wang, Zheming, Wang, Hongfei, & Walker, Robert A. Organic Enrichment at Aqueous Interfaces: Cooperative Adsorption of Glucuronic Acid to DPPC Monolayers Studied with Vibrational Sum Frequency Generation. United States. doi:10.1021/acs.jpca.9b02255.
Link, Katie A., Spurzem, Gabrielle, Tuladhar, Aashish, Jessamy-Chase, Zizwe A., Wang, Zheming, Wang, Hongfei, and Walker, Robert A. Fri . "Organic Enrichment at Aqueous Interfaces: Cooperative Adsorption of Glucuronic Acid to DPPC Monolayers Studied with Vibrational Sum Frequency Generation". United States. doi:10.1021/acs.jpca.9b02255.
@article{osti_1571276,
title = {Organic Enrichment at Aqueous Interfaces: Cooperative Adsorption of Glucuronic Acid to DPPC Monolayers Studied with Vibrational Sum Frequency Generation},
author = {Link, Katie A. and Spurzem, Gabrielle and Tuladhar, Aashish and Jessamy-Chase, Zizwe A. and Wang, Zheming and Wang, Hongfei and Walker, Robert A.},
abstractNote = {Surface tension, surface-specific vibrational spectroscopy and differential scanning calorimetry measurements were all used to test cooperative adsorption of glucuronic acid (GU) to DPPC monolayers adsorbed to the aqueous/vapor interface. Experiments were performed using GU solutions prepared in Millipore water and in carbonate/bicarbonate solutions buffered to a pH of 9.0. The effects of GU on DPPC monolayer structure and organization were carried out with tightly packed monolayers (40 Å2/DPPC) and monolayers in their liquid condensed phase (55 Å2/molecule). Surface tension data show that GU concentrations of 50 mM lead to expanded DPPC monolayers with diminished surface tensions (or higher surface pressures) at a given DPPC coverage relative to monolayers on pure water. With unbuffered solutions, GU induces significant ordering within liquid condensed monolayers although the effects of GU on tightly packed DPPC monolayers are less pronounced. GU also induces a second, higher melting temperature in DPPC vesicles implying that GU (at sufficiently high concentrations) strengthens lipid-lipid cohesion, possibly by replacing water solvating the DPPC headgroups. Together, these observations all support a cooperative adsorption mechanism. In buffer solutions, the effects of dissolved GU on DPPC structure and organization are muted. Only at sufficiently high GU concentrations (when the solution’s buffering capacity has been exceeded) do the data again show evidence of cooperative adsorption. These findings place limits on cooperative adsorption’s ability to enrich interfacial organic content in alkaline environmental systems such as oceans.},
doi = {10.1021/acs.jpca.9b02255},
journal = {Journal of Physical Chemistry A},
number = 26,
volume = 123,
place = {United States},
year = {2019},
month = {7}
}