In Situ Measurement of the FT-IR Spectra of Phospholipid Monolayers at the Air/Water Interface

1988 ◽  
Vol 42 (1) ◽  
pp. 138-141 ◽  
Author(s):  
Richard A. Dluhy ◽  
Norman A. Wright ◽  
Peter R. Griffiths
Keyword(s):  
Detailed Examination ◽  
In Situ Measurement ◽  
Surface Films ◽  
Water Interface ◽  
Monolayer Films ◽  
Air Water Interface ◽  
Monomolecular Films ◽  
Acyl Chains ◽  
Ft Ir

External reflection Fourier transform infrared spectroscopy has been applied to the in situ measurement of the infrared spectra of insoluble phospholipid monolayer films that were spread at the air/water interface. The spreading conditions for the phospholipids [1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC)] were chosen to mimic those of liquid-condensed and liquid-expanded surface films, respectively. It is shown that the infrared reflection spectra can identify vibrations due to the hydrocarbon acyl chains, carbonyl ester, and phosphate groups for these monolayer films on water. Detailed examination of the frequencies and polarization properties of the C-H stretching region shows that the liquid-condensed DSPC acyl chains are in a rigid, mostly all-trans configuration, while the liquid-expanded DMPC acyl chains are highly fluid. The spectra demonstrate that the external reflection FT-IR experiment can differentiate between the physical conformation of monomolecular films when water is used as a reflective substrate.

In Situ Measurement of the Displacement of Protein Films from the Air/Water Interface by Surfactant

2001 ◽  
Vol 2 (3) ◽  
pp. 1001-1006 ◽  
Author(s):  
Alan R. Mackie ◽  
A. Patrick Gunning ◽  
Mike J. Ridout ◽  
Peter J. Wilde ◽  
J. Rodriguez Patino
Keyword(s):  
In Situ Measurement ◽  
Water Interface ◽  
Protein Films ◽  
Air Water Interface

Design and Interfacing of an Automated Langmuir-Type Film Balance to an FT-IR Spectrometer

1988 ◽  
Vol 42 (7) ◽  
pp. 1289-1293 ◽  
Author(s):  
Richard A. Dluhy ◽  
Melody L. Mitchell ◽  
Thomas Pettenski ◽  
Jeffery Beers
Keyword(s):  
Focal Point ◽  
High Surface ◽  
Monolayer Film ◽  
Monolayer Films ◽  
Langmuir Film Balance ◽  
Air Water Interface ◽  
Ft Ir ◽  
Film Balance ◽  
Ft Ir Spectroscopy

We report the design of a surface analysis accessory that allows for the use of external reflection FT-IR spectroscopy to investigate the structure of insoluble monolayer films in situ at the air/water interface. The Langmuir film balance constructed for this purpose is optimized to contain the monolayer film at the focal point of the infrared beam, as well as to generate high surface pressures within the film. The optical interfacing of the film balance to an FT-IR spectrometer is also described. Results are presented for a representative surface pressure/molecular area isotherm and infrared spectrum for a phospholipid monolayer film.

Sampling and analysis of the air-water interface with SEM and EDS of microlayers

1989 ◽  
Vol 47 ◽  
pp. 1004-1005
Author(s):  
Randall W. Smith ◽  
John Dash
Keyword(s):  
Heavy Metals ◽  
Surface Microlayer ◽  
Surface Films ◽  
Water Interface ◽  
Physical Processes ◽  
Infrared Spectroscopic Analysis ◽  
Eds Analysis ◽  
Air Water Interface ◽  
Significant Area ◽  
Bulk Chemical

The structure of the air-water interface forms a boundary layer that involves biological ,chemical geological and physical processes in its formation. Freshwater and sea surface microlayers form at the air-water interface and include a diverse assemblage of organic matter, detritus, microorganisms, plankton and heavy metals. The sampling of microlayers and the examination of components is presently a significant area of study because of the input of anthropogenic materials and their accumulation at the air-water interface. The neustonic organisms present in this environment may be sensitive to the toxic components of these inputs. Hardy reports that over 20 different methods have been developed for sampling of microlayers, primarily for bulk chemical analysis. We report here the examination of microlayer films for the documentation of structure and composition.Baier and Gucinski reported the use of Langmuir-Blogett films obtained on germanium prisms for infrared spectroscopic analysis (IR-ATR) of components. The sampling of microlayers has been done by collecting fi1ms on glass plates and teflon drums, We found that microlayers could be collected on 11 mm glass cover slips by pulling a Langmuir-Blogett film from a surface microlayer. Comparative collections were made on methylcel1ulose filter pads. The films could be air-dried or preserved in Lugol's Iodine Several slicks or surface films were sampled in September, 1987 in Chesapeake Bay, Maryland and in August, 1988 in Sequim Bay, Washington, For glass coverslips the films were air-dried, mounted on SEM pegs, ringed with colloidal silver, and sputter coated with Au-Pd, The Langmuir-Blogett film technique maintained the structure of the microlayer intact for examination, SEM observation and EDS analysis were then used to determine organisms and relative concentrations of heavy metals, using a Link AN 10000 EDS system with an ISI SS40 SEM unit. Typical heavy microlayer films are shown in Figure 3.

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