In Situ Studies of Coatings on Metal Wires by FT-IR External Reflectance Spectroscopy

Diffuse reflectance FT-IR spectroscopy was originally developed for particulate samples dispersed in KBr powders. Now, by using ellipsoid mirrors for scattered light collection, we have taken advantage of the collection efficiency of diffuse reflectance optics and have extended their use to an in situ study of coatings on metal wires and of the broken surface of a reinforcement wire as well. The result is that spectra of coatings on wire show good overall agreement with external reflection spectra of thin films. The technique we have developed has an advantage over infrared attenuated total reflection (ATR), in that there is no optical contact problem between the wire sample and ATR crystal.

Download Full-text

Mesoporous Zirconia Coating for Sensing Applications Using Attenuated Total Reflection Fourier Transform Infrared (ATR FT-IR) Spectroscopy

Applied Spectroscopy ◽

10.1177/00037028211057156 ◽

2021 ◽

pp. 000370282110571

Author(s):

Dominik Wacht ◽

Mauro David ◽

Borislav Hinkov ◽

Hermann Detz ◽

Andreas Schwaighofer ◽

...

Keyword(s):

Fourier Transform ◽

Ir Spectroscopy ◽

Total Reflection ◽

Attenuated Total Reflection ◽

In Situ Monitoring ◽

Zirconia Coating ◽

Mesoporous Zirconia ◽

Ft Ir ◽

Ft Ir Spectroscopy

Mid-infrared attenuated total reflection (ATR) spectroscopy is a powerful tool for in situ monitoring of various processes. Mesoporous silica, an extensively studied material, has already been applied in sensing schemes due to its high surface area and tunable surface chemistry. However, its poor chemical stability in aqueous solutions at pH values higher than 8 and strong absorption below 1250 cm−1 limits its range of applications. To circumvent these problems, a mesoporous zirconia coating on ATR crystals was developed. Herein, the synthesis, surface modification, and characterization of ordered mesoporous zirconia films on Si wafers and Si-ATR crystals are presented. The modified coating was applied in sensing schemes using aromatic and aliphatic nitriles in aqueous solution as organic pollutants. The mesoporous zirconia coating shows strong chemical resistance when kept in alkaline solution for 72 h. The success of surface modification is confirmed using Fourier transform infrared (FT-IR) spectroscopy and contact angle measurements. Benzonitrile and valeronitrile in water are used as model analytes to evaluate the enrichment performance of the film. The experimental results are fitted using Freundlich isotherms, and enrichment factors of 162 and 26 are calculated for 10 mg L−1 benzonitrile and 25 mg L−1 valeronitrile in water, respectively. Limits of detection of 1 mg L−1 for benzonitrile and 11 mg L−1 for valeronitrile are obtained. The high chemical stability of this coating allows application in diverse fields such as catalysis with the possibility of in situ monitoring using FT-IR spectroscopy.

Download Full-text

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

Applied Spectroscopy ◽

10.1177/0003702818779799 ◽

2018 ◽

Vol 72 (9) ◽

pp. 1396-1403 ◽

Cited By ~ 1

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.

Download Full-text

Pitfalls and benefits of in situ and operando diffuse reflectance FT-IR spectroscopy (DRIFTS) applied to catalytic reactions

Reaction Chemistry & Engineering ◽

10.1039/c5re00018a ◽

2016 ◽

Vol 1 (2) ◽

pp. 134-141 ◽

Cited By ~ 23

Author(s):

F. C. Meunier

Keyword(s):

Ir Spectroscopy ◽

Diffuse Reflectance ◽

Catalytic Reactions ◽

Ft Ir ◽

Ft Ir Spectroscopy

The procedures and conditions that need to be fulfilled to be able to carry out appropriate in situ and operando diffuse reflectance FT-IR (DRIFTS) analyses are discussed.

Download Full-text

Fatty Acid Prediction in Bovine Milk by Attenuated Total Reflection Infrared Spectroscopy after Solvent-Free Lipid Separation

Foods ◽

10.3390/foods10051054 ◽

2021 ◽

Vol 10 (5) ◽

pp. 1054

Author(s):

Christopher Akhgar ◽

Vanessa Nürnberger ◽

Marlene Nadvornik ◽

Margit Velik ◽

Andreas Schwaighofer ◽

...

Keyword(s):

Fatty Acid ◽

Milk Fat ◽

Regression Models ◽

Bovine Milk ◽

Attenuated Total Reflection ◽

Solvent Free ◽

Novel Approach ◽

Whole Milk ◽

Ft Ir ◽

Ft Ir Spectroscopy

In the present study, a novel approach for mid-infrared (IR)-based prediction of bovine milk fatty acid composition is introduced. A rapid, solvent-free, two-step centrifugation method was applied in order to obtain representative milk fat fractions. IR spectra of pure milk lipids were recorded with attenuated total reflection Fourier-transform infrared (ATR-FT-IR) spectroscopy. Comparison to the IR transmission spectra of whole milk revealed a higher amount of significant spectral information for fatty acid analysis. Partial least squares (PLS) regression models were calculated to relate the IR spectra to gas chromatography/mass spectrometry (GC/MS) reference values, providing particularly good predictions for fatty acid sum parameters as well as for the following individual fatty acids: C10:0 (R2P = 0.99), C12:0 (R2P = 0.97), C14:0 (R2P = 0.88), C16:0 (R2P = 0.81), C18:0 (R2P = 0.93), and C18:1cis (R2P = 0.95). The IR wavenumber ranges for the individual regression models were optimized and validated by calculation of the PLS selectivity ratio. Based on a set of 45 milk samples, the obtained PLS figures of merit are significantly better than those reported in literature using whole milk transmission spectra and larger datasets. In this context, direct IR measurement of the milk fat fraction inherently eliminates covariation structures between fatty acids and total fat content, which poses a common problem in IR-based milk fat profiling. The combination of solvent-free lipid separation and ATR-FT-IR spectroscopy represents a novel approach for fast fatty acid prediction, with the potential for high-throughput application in routine lab operation.

Download Full-text

Diffuse Reflectance FT-IR Characterization of Active Sites under Reaction Conditions: The Production of Oxygenates in the CO/H2 Reaction

Applied Spectroscopy ◽

10.1366/0003702944027345 ◽

1994 ◽

Vol 48 (10) ◽

pp. 1208-1212 ◽

Cited By ~ 7

Author(s):

J. J. Benítez ◽

I. Carrizosa ◽

J. A. Odriozola

Keyword(s):

Infrared Spectra ◽

Active Sites ◽

Diffuse Reflectance ◽

Reaction Conditions ◽

In Situ Drifts ◽

Ft Ir

The reactivity of a Lu2O3-promoted Rh/Al2O3 catalyst in the CO/H2 reaction is reported. Methane, heavier hydrocarbons, methanol, and ethanol are obtained. In situ DRIFTS has been employed to record the infrared spectra under the actual reaction conditions. The structure of the observed COads DRIFTS bands has been resolved into its components. The production of oxygenates (methanol and ethanol) has been correlated with the results of the deconvolution calculation. Specific sites for the production of methanol and ethanol in the CO/H2 reaction over a Rh,Lu2O3/Al2O3 catalyst are proposed.

Download Full-text

Use of Attenuated Total Reflection Fourier Transform Infrared (ATR FT-IR) Spectroscopy in Direct, Nondestructive, and Rapid Assessment of Developmental Cotton Fibers Grown in Planta and in Culture

Applied Spectroscopy ◽

10.1366/15-07876 ◽

2015 ◽

Vol 69 (8) ◽

pp. 1004-1010 ◽

Cited By ~ 14

Author(s):

Yongliang Liu ◽

Hee-Jin Kim

Keyword(s):

Fourier Transform ◽

Ir Spectroscopy ◽

Rapid Assessment ◽

Fourier Transform Infrared ◽

Total Reflection ◽

Attenuated Total Reflection ◽

Cotton Fibers ◽

In Planta ◽

Ft Ir ◽

Ft Ir Spectroscopy

Download Full-text

Applications of Diffuse Reflectance FT-IR to Pigment Photodecomposition in Paint

Applied Spectroscopy ◽

10.1366/0003702824638809 ◽

1982 ◽

Vol 36 (2) ◽

pp. 155-157 ◽

Cited By ~ 19

Author(s):

D. B. Chase ◽

R. L. Amey ◽

W. G. Holtje

Keyword(s):

Ir Spectroscopy ◽

Infrared Spectra ◽

Diffuse Reflectance ◽

Spectral Subtraction ◽

Ft Ir ◽

Ft Ir Spectroscopy

Diffuse reflectance FT-IR spectroscopy is used to obtain infrared spectra of paints directly on paper panels. The binder contribution to the spectrum can be effectively eliminated by spectral subtraction and the spectra of photodecomposition products are obtained. Comparison with reference spectra allows the determination of the photodecomposition mechanism.

Download Full-text

Monitoring the Interfacial Polymerization of Piperazine and Trimesoyl Chloride with Hydrophilic Interlayer or Macromolecular Additive by in-situ FT-IR Spectroscopy

10.20944/preprints201911.0012.v1 ◽

2019 ◽

Author(s):

Xi Yang

Keyword(s):

Ir Spectroscopy ◽

Reaction Rate ◽

Interfacial Polymerization ◽

Reaction System ◽

Reaction Rates ◽

Water Permeation ◽

Ft Ir ◽

Trimesoyl Chloride ◽

Ft Ir Spectroscopy

The interfacial polymerization (IP) of piperazine (PIP) and trimesoyl chloride (TMC) has been extensively utilized to synthesize the nanofiltration (NF) membrane. However, it is still a huge challenge to monitor the IP reaction, because of the fast reaction rate and the formed ultra-thin film. Herein, two effective strategies are applied to reduce the IP reaction rate: (1) the introduction of hydrophilic interlayers between the porous substrate and the formed polyamide layer; (2) the addition of macromolecular additives in the aqueous solution of PIP. As a result, in-situ FT-IR spectroscopy was firstly used to monitor the IP reaction of PIP/TMC reaction system, with hydrophilic interlayers or macromolecular additives. Moreover, we study the formed polyamide layer growth on the substrate, in a real-time manner. The in-situ FT-IR experimental results confirm that the IP reaction rates are effectively suppressed and the formed polyamide thickness reduces from 138±24 nm to 46±2 nm. Furthermore, the optimized NF membrane with excellent performance are consequently obtained, which include the boosted water permeation flux about 141~238 (L·m2·h/MPa) and superior salt rejection of Na2SO4 > 98.4%.

Download Full-text