Diffusion Measurements Using FT-IR ATR Spectroscopy: Lubricant Diffusion in Polypropylene

2002 ◽  
Vol 56 (4) ◽  
pp. 509-514 ◽  
Author(s):  
Xiaohua Yi ◽  
Karen Nerbonne ◽  
John Pellegrino
Keyword(s):  
Current Model ◽  
Mineral Oil ◽  
Attenuated Total Reflection ◽  
Lubricant Layer ◽  
Polymer Interfaces ◽  
Time Resolved ◽  
Polymer Sample ◽  
Ft Ir ◽  
Atr Spectroscopy ◽  
Poly Propylene

We present an experimental method for measuring diffusion of lubricants (or any highly viscous fluid) in polymers using Fourier transform infrared (FT-IR) attenuated total reflection (ATR) spectroscopy. Unlike the conventional FT-IR ATR diffusion measurement, in which a polymer sample is sandwiched between the penetrant and an internal reflection element (IRE), in this method, a thin layer of penetrant (for example, a lubricant) is sandwiched between the IRE and the polymer sample. This allows accurate control and measurement of the thickness of the lubricant layer, which, in turn, facilitates subsequent data analysis. The diffusion is studied by monitoring the time-resolved change in absorbance of either a unique polymer or penetrant band. A feature of this new method is that it can provide an estimate of solubility, as well as an estimate of the diffusivity of the penetrant in the polymer. Using this method, we studied the diffusion of mineral oil and a commercial fluorocarbon ether lubricant (Krytox® 143AC‡) in poly(propylene) (PP) film at room temperature. The experimental data was modeled using a Fickian model with impermeable and saturated boundary conditions applied at the IRE/lubricant and lubricant/polymer interfaces, respectively. The diffusivity and solubility of mineral oil in PP were found to be 1.34 ± 0.35 (×10−10) cm2/s and 0.77 ± 0.13 (×10−2) g/g of PP, respectively. The current model was unable to quantitatively describe the diffusion of the Krytox® 143AC in the PP, possibly due to excessive swelling.

Atr/Ft-Ir Difference Spectroscopy of Biological Matter with Microsecond Time Resolution

1996 ◽  
Vol 50 (5) ◽  
pp. 588-596 ◽  
Author(s):  
Joachim Heberle ◽  
Christian Zscherp
Keyword(s):  
Attenuated Total Reflection ◽  
High Temporal Resolution ◽  
Difference Spectroscopy ◽  
Difference Spectra ◽  
Time Resolved ◽  
Precise Control ◽  
Biological Matter ◽  
Vis Spectroscopy ◽  
Ft Ir ◽  
Atr Spectroscopy

Attenuated total reflection (ATR) spectroscopy allows precise control of external parameters vital for proper functioning of biological matter. For the first time in biospectroscopy, ATR difference spectroscopy has been combined with the step-scan technique. The current setup integrates a broad frequency range (800–25,000 cm−1) with high temporal resolution (5 μs). Vibrations are detected that arise from single amino acids (<10−3 absorbance units) of the chromoprotein bacteriorhodopsin. Time-resolved ATR/FT-IR difference spectra are compared with conventional transmission spectra. The high mirror stability enables time-resolved FT-vis spectroscopy of the same sample with the same instrument. Potential applications even to non-light-absorbing biomaterial are discussed.

Chemical Stability of SC1-Cleaned Hydrogen Terminated Si(100) Surfaces

1995 ◽  
Vol 386 ◽  
Author(s):  
C. H. Bjorkman ◽  
H. Nishimura ◽  
T. Yamazaki ◽  
J. L. Alay ◽  
M. Fukuda ◽  
...  
Keyword(s):  
Chemical Stability ◽  
Photoelectron Spectroscopy ◽  
Surface Concentration ◽  
Attenuated Total Reflection ◽  
Surface Contamination ◽  
Loading Conditions ◽  
Ft Ir ◽  
Atr Spectroscopy ◽  
Water Rinsing ◽  
Water Rinse

ABSTRACTSurface contamination and chemical stability of hydrogen terminated Si(100) surfaces have been studied using Fourier Transform Infrared Attenuated Total Reflection (FT-IR-ATR) spectroscopy and X-ray Photoelectron Spectroscopy (XPS). Hydrogen terminated Si(100) is obtained by removing the chemical oxide, formed in a low-concentration-NH4OH SC1 clean, in various HF based solutions. Using standard cleaning and loading conditions, we find a direct correlation between surface roughness and the amount of adsorbed C contamination. Oxidation during water rinsing and wafer loading observed by both FT-IR-ATR and XPS indicates that dihydride terminated silicon atoms are preferentially oxidized. Optimizing the water rinse and wafer loading conditions reduces total atomic concentration of C, O, and F surface contamination from 20–30 at.% to less than 6 at.%. These clean surfaces enable XPS-identification of the Si-Hx components of the Si 2p core-level spectra as well as estimation of the relative surface concentration of Si-Hx and contamination species.

scholarly journals Designing Zirconium Coated Polystyrene Colloids and Application

2009 ◽  
Vol 2009 ◽  
pp. 1-6 ◽  
Author(s):  
Diana Chira ◽  
Seong S. Seo
Keyword(s):  
Zirconium Oxychloride ◽  
Nerve Agent ◽  
Attenuated Total Reflection ◽  
Practical Application ◽  
Sem Images ◽  
X Ray ◽  
Ir Studies ◽  
Ft Ir ◽  
Amine Groups ◽  
Atr Spectroscopy

A simple technique has been developed to prepare core colloids that are modified using zirconium oxychloride, based on heating a solution of core colloid composites, consisting of poly (ethylenimine) (PEI) and zirconium oxychloride. The interaction of zirconium oxychloride with the polystyrene (PS) core colloids has been investigated using Fourier transform-infrared spectroscopy (FT-IR), energy dispersive X-ray spectroscopy (EDX), and scanning electron microscopy (SEM) data. FT-IR studies confirm the occurrence of amine groups present in PEI which are oxidized to carboxyl groups after the reaction. The EDX data and the SEM images confirm the presence of zirconium particles immobilized on the polystyrene surfaces. Demeton, a highly toxic nerve agent, was used due to its ability to easily bind through its organophosphate group illustrating a practical application of the PS-PEI-Zr particles. Attenuated Total Reflection (ATR) Spectroscopy was used to assess the interactions between the toxic nerve agent demeton-S and the PS-PEI-Zr particles. The results show that the presented technique for coating polystyrene core colloids with zirconium was successfully accomplished, and the newly formed particles easily bond with demeton agents through the P=O functional group.

Discrimination of Soil-Borne Fungi Using Fourier Transform Infrared Attenuated Total Reflection Spectroscopy

2008 ◽  
Vol 62 (3) ◽  
pp. 302-305 ◽  
Author(s):  
Raphael Linker ◽  
Leah Tsror(LAHKIM)
Keyword(s):  
Fourier Transform ◽  
Success Rate ◽  
Fourier Transform Infrared ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Economic Damage ◽  
Genus Level ◽  
Ft Ir ◽  
Atr Spectroscopy ◽  
Soil Borne Fungi

Fourier transform infrared (FT-IR) attenuated total reflection (ATR) spectroscopy was used to discriminate five commonly encountered soil-borne fungi that cause severe economic damage to agriculture: Colletotrichum, Fusarium, Pythium, Rhizoctonia, and Verticillium. Contrary to previous studies related to microorganism discrimination using FT-IR-ATR spectroscopy, the pathogen samples were not dried on the ATR crystal, which is a time-consuming operation. Rather, after removing some pathogen filaments from the solution using tweezers, these were placed directly on a flat ATR crystal and pressure was applied using a pressure clamp. Following water subtraction, baseline correction, and normalization of the spectra, principal component analysis was used as a data-reduction step and canonical variate analysis was used for discrimination. Discrimination was performed at the genus level and at the strain level for Colletotrichum. For discrimination between the five fungi at the genus level, the success rate for the validation samples ranged from 75% to 89%. For discrimination between the two Colletotrichum strains, the success rate was 78%. Comparison with spectra of similar fungi dried on the ATR crystal showed that both types of spectra were very similar, indicating that drying the samples on the ATR crystal is not required and can be replaced by mathematical post-processing of the spectra. For routine analyses that involve rapid screening of very large amounts of samples, this approach allows for increasing significantly the number of samples that can be analyzed daily.

Quantitative Analysis of Adsorbed Serum Albumin on Segmented Polyurethane Using FT-IR/ATR Spectroscopy

1992 ◽  
Vol 46 (11) ◽  
pp. 1644-1648 ◽  
Author(s):  
J. S. Jeon ◽  
R. P. Sperline ◽  
S. Raghavan
Keyword(s):  
Serum Albumin ◽  
Solution Concentration ◽  
Attenuated Total Reflection ◽  
Stratified Medium ◽  
Bulk Solution ◽  
Total Peak Area ◽  
Ft Ir ◽  
Adsorption Density ◽  
Flowing System ◽  
Atr Spectroscopy

FT-IR attenuated total reflection (ATR) spectroscopy was applied to quantitatively determine the extent of bovine serum albumin adsorbed onto a biomedical-grade poly(ether)urethane film deposited on a ZnSe internal reflection element (IRE). The method of adsorption density determination was based on the optical principles for a stratified medium consisting of three layers. The spectral peak area due to bulk solution was less than 1% of total peak area. The measured adsorption density of albumin in a flowing system was 3.9 μg/cm2 at a solution concentration of 4.5 g/100 mL.

Depth Profiling of the Degree of Cure during the Photopolymerization of Acrylates Studied by Real-Time FT-IR Attenuated Total Reflection Spectroscopy

2002 ◽  
Vol 56 (11) ◽  
pp. 1403-1412 ◽  
Author(s):  
Tom Scherzer
Keyword(s):  
Real Time ◽  
Depth Profiling ◽  
Finite Depth ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Depth Of Penetration ◽  
Degree Of Cure ◽  
Uv Absorbers ◽  
Ft Ir ◽  
Atr Spectroscopy

Real-time Fourier transform infrared attenuated total reflection (FT-IR/ATR) spectroscopy was used to study the depth profile of the conversion during photopolymerization reactions. The method is based on the UV irradiation of coatings of different thicknesses on the ATR crystal. Due to the finite depth of penetration of the infrared probe signal into the sample, conversion is analyzed only in a narrow layer at the bottom of the coating. The method was used to characterize the effect of photo-initiators on the depth of cure in acrylate coatings. The self-screening of a strongly absorbing morpholino ketone photo-initiator and the photobleaching of a bisacylphosphine oxide initiator are demonstrated. Moreover, depth profiling studies on the filter effect of UV absorbers and on the influence of pigmentation in white-pigmented systems will be reported.

scholarly journals Evaluation of Silicon Wafer-Based Internal Reflection Elements for Use with in Situ Fourier Transform Infrared (FT-IR) Spectroscopy

2018 ◽  
Vol 72 (9) ◽  
pp. 1396-1403 ◽  
Author(s):  
Brent A. Sperling ◽  
Berc Kalanyan
Keyword(s):  
Silicon Wafer ◽  
Polarization State ◽  
Cell Polarization ◽  
Attenuated Total Reflection ◽  
Internal Reflection ◽  
Ft Ir ◽  
Atr Spectroscopy ◽  
Lower Noise ◽  
Ft Ir Spectroscopy

Silicon wafer-based internal reflection elements (IREs) present many practical advantages over the prisms conventionally used for attenuated total reflection (ATR) spectroscopy in the infrared. We examine two methods of using minimally prepared IREs that have appeared in the literature, edge-coupled (EC) and prism-coupled (PC), in conjunction with a liquid flow cell. Polarization measurements show that radiation entering the PC-IRE becomes depolarized due to stress-induced birefringence, and transmission through the edge of the EC-IRE also affects the polarization state. Quantification of the noise and a calibration using a series of sodium acetate solutions show the sensitivity of the PC-IRE outweighs the lower noise obtainable with the EC-IRE.

Attenuated (but Not Total) Internal Reflection FT-IR Spectroscopy of Thin Films

2002 ◽  
Vol 56 (5) ◽  
pp. 665-669 ◽  
Author(s):  
Will Cantrell ◽  
George E. Ewing
Keyword(s):  
Theoretical Basis ◽  
Total Internal Reflection ◽  
Spectroscopic Technique ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Internal Reflection ◽  
Geometric Constraints ◽  
Ft Ir ◽  
Atr Spectroscopy ◽  
Ft Ir Spectroscopy

We present a spectroscopic technique that is a hybrid between reflection-absorption and attenuated total reflection (ATR) spectroscopy. The method, which we call attenuated internal reflection (AIR), is suitable for the investigation of thin film liquids on non-or weakly absorbing substrates. In AIR the interrogating infrared beam is not exposed to vapor that may be associated with the film, but unlike ATR there are few geometric constraints on the substrate. We show the theoretical basis for the method and results from experiments demonstrating its use.

scholarly journals Spectroscopy as a useful tool for the identification of changes with time in post-mortem vitreous humor for forensic toxicology purposes

2021 ◽  
Author(s):  
Anna Wójtowicz ◽  
Agata Mitura ◽  
Renata Wietecha-Posłuszny ◽  
Rafał Kurczab ◽  
Marcin Zawadzki
Keyword(s):  
Ir Spectra ◽  
Forensic Toxicology ◽  
Principal Component ◽  
Hierarchical Cluster ◽  
Vitreous Humor ◽  
Attenuated Total Reflection ◽  
Glass Slides ◽  
Added Benefit ◽  
Ft Ir ◽  
Non Destructive

AbstractVitreous humor (VH) is an alternative biological matrix with a great advantage of longer availability for analysis due to the lack of many enzymes. The use of VH in forensic toxicology may have an added benefit, however, this application requires rapid, simple, non-destructive, and relatively portable analytical analysis methods. These requirements may be met by Fourier transform infrared spectroscopy technique (FT-IR) equipped with attenuated total reflection accessory (ATR). FT-IR spectra of vitreous humor samples, deposited on glass slides, were collected and subsequent chemometric data analysis by means of Hierarchical Cluster Analysis and Principal Component Analysis was conducted. Differences between animal and human VH samples and human VH samples stored for diverse periods of time were detected. A kinetic study of changes in the VH composition up to 2 weeks showed the distinction of FT-IR spectra collected on the 1st and 14th day of storage. In addition, data obtained for the most recent human vitreous humor samples—collected 3 and 2 years before the study, presented successful discrimination of all time points studied. The method introduced was unable to detect mephedrone addition to VH in the concentration of 10 µg/cm3. Graphic abstract

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