New Technique for Determining the Optical Constants of Liquids

2002 ◽  
Vol 56 (7) ◽  
pp. 928-934 ◽  
Author(s):  
C. Dale Keefe ◽  
Jason K. Pearson
Keyword(s):  
Optical Constants ◽  
Reflectance Spectrum ◽  
Strong Absorption ◽  
New Technique ◽  
Attenuated Total Reflectance ◽  
Absorption Bands ◽  
Total Reflectance ◽  
Specular Reflectance ◽  
Volatile Liquids ◽  
Atr Spectroscopy

The traditional techniques of transmission and attenuated total reflectance (ATR) spectroscopy for determining the optical constants of liquids are not practical or reliable for very strong absorption bands. Specular reflectance can be used in these cases, but for volatile liquids it is impossible to separate the reflectance spectrum of the liquid from the absorption spectrum of the vapor above the liquid. Methods using special cells have been described in the literature to prevent the liquid from evaporating. In this paper, a similar technique that makes use of traditional transmission cells is presented. It is shown that this new technique generates k(ν˜) spectra for strong absorption bands that are accurate to approximately 2%.

scholarly journals The Influence of Curing Regimes in Self-Healing of Nano-Modified Cement Pastes

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5301
Author(s):  
Maria Stefanidou ◽  
Eirini-Chrysanthi Tsardaka ◽  
Aspasia Karozou
Keyword(s):  
Sem Analysis ◽  
Attenuated Total Reflectance ◽  
Self Healing ◽  
Nano Silica ◽  
Cement Pastes ◽  
Curing Conditions ◽  
Total Reflectance ◽  
Atr Spectroscopy ◽  
Curing Regimes ◽  
Early Healing

The present study proposes nano-calcium oxide (NC) and nano-silica (NS) particles as healing agents in cement pastes, taking into account the curing conditions. Two series of specimens were treated in water and under wetting-drying cycles. The addition of NC (1.5%wt of binder) triggered early healing since cracks were healed within 14 days in underwater immersion and before 28 days at wetting-drying cycles. Attenuated Total Reflectance (ATR) spectroscopy and SEM analysis revealed that the healing products were mainly aragonite and calcite in water conditions and more amorphous carbonates under wetting-drying cycles. The combination of NS and NC (3.0%wt in total) offered healing under both curing conditions before 28 days. The presence of NS assisted toward porosity refinement and NC increased the carbonates’ content. The newly formed material was dense, and its elemental analysis by SEM revealed the C-S-H compounds that were also verified by ATR.

scholarly journals FTIR-ATR Spectroscopy Combined with Multivariate Regression Modeling as a Preliminary Approach for Carotenoids Determination in Cucurbita spp.

2020 ◽  
Vol 10 (11) ◽  
pp. 3722
Author(s):  
Natalia Quijano-Ortega ◽  
Carlos Alberto Fuenmayor ◽  
Carlos Zuluaga-Dominguez ◽  
Consuelo Diaz-Moreno ◽  
Sanín Ortiz-Grisales ◽  
...  
Keyword(s):  
Organic Solvents ◽  
Carotenoid Content ◽  
Future Application ◽  
Attenuated Total Reflectance ◽  
Total Reflectance ◽  
Total Carotenoid Content ◽  
Three Samples ◽  
Freeze Dried ◽  
Using Data ◽  
Atr Spectroscopy

Quantitative analysis of carotenoids has been extensively reported using UV-Vis spectrophotometry and chromatography, instrumental techniques that require complex extraction protocols with organic solvents. Fourier transform infrared spectroscopy (FTIR) is a potential alternative for simplifying the analysis of food constituents. In this work, the application of FTIR with attenuated total reflectance (ATR) was evaluated for the determination of total carotenoid content (TCC) in Cucurbita spp. samples. Sixty-three samples, belonging to different cultivars of butternut squash (C. moschata) and pumpkin (C. maxima), were selected and analyzed with FTIR- ATR (attenuated total reflectance). Three different preparation protocols for samples were followed: homogenization (A), freeze-drying (B), and solvent extraction (C). The recorded spectra were used to develop regression models by Partial Least Squares (PLS), using data from TCC, determined by UV-Vis spectrophotometry. The PLS regression model obtained with the FTIR data from the freeze-dried samples, using the spectral range 920–3000 cm−1, had the best figures of merit (R2CAL of 0.95, R2PRED of 0.93 and RPD of 3.78), being reliable for future application in agriculture. This approach for carotenoid determination in pumpkin and squash avoids the use of organic solvents. Moreover, these results are a rationale for further exploring this technique for the assessment of specific carotenoids in food matrices.

Milk Inspection by THz Attenuated Total Reflectance (THz-ATR) Spectroscopy

2011 ◽  
Author(s):  
Hirotaka Naito ◽  
Yuichi Ogawa ◽  
Tetsuhito Suzuki ◽  
Naoshi Kondo
Keyword(s):  
Attenuated Total Reflectance ◽  
Total Reflectance ◽  
Atr Spectroscopy

Removal of Organic Dyes by Using Cellulose-Chitosan-Nanowires Hybrid Composition Beads

2020 ◽  
Vol 1002 ◽  
pp. 468-477
Author(s):  
Alarqam Zyaad Tareq
Keyword(s):  
Organic Dyes ◽  
Hybrid Composites ◽  
Attenuated Total Reflectance ◽  
Mechanical And Thermal Properties ◽  
Anionic Dyes ◽  
Chitosan Beads ◽  
Total Reflectance ◽  
Removal Capacity ◽  
Atr Spectroscopy ◽  
Dyes Removal

Organic dyes are mostly used in textile, paper, plastic, and other industries. These industries can be toxic and harmful to environment and human. Adsorption is the most efficient method to control wastewater that contains dyes. Cellulose-Chitosan beads was mainly used in the adsorption. To increase and enhance the organic dyes removal capacity of these beads, titanium dioxide nanowires (TiO2Nw) as used to achieve novel Cs-Cell-nanowires hybrid composites. Ultralong hydroxyapatite nanowires was prepared and used to enhance the mechanical and thermal properties of beads. On the other hand, the beads composition was prepared with spherical white shape. Internal structure of beads and other composition were studied by using Attenuated Total Reflectance (ATR) spectroscopy, scanning electron microscopy (SEM), lazer diffraction (LD), thermal analysis (TG, DSC, DTG, and DTA). The beads are tested with five different organic dyes which include Methyl blue (MB), Acid alizarin Black (AAB) as cationic dyes, and Methyl orang (MO), Methyl red (MR) and Eriochrome black T (EBT) as anionic dyes. The results indicate that the beads have the ability to remove MB, EBT,AAB but do not have the ability to remove MO and MR. So, the Cell-CS- HAPNw- TiO2Nw beads can be considered as the promising adsorption for MB, EBT, and AAB from aqueous solutions.

Multivariate Determination of Sugar Powders by Attenuated Total Reflectance Infrared Spectroscopy

1993 ◽  
Vol 47 (4) ◽  
pp. 452-457 ◽  
Author(s):  
N. Dupuy ◽  
M. Meurens ◽  
B. Sombret ◽  
P. Legrand ◽  
J.P. Huvenne
Keyword(s):  
Quantitative Analysis ◽  
Attenuated Total Reflectance ◽  
Infrared Spectrometry ◽  
Infrared Analysis ◽  
Total Reflectance ◽  
Regression Methods ◽  
Peak Resolution ◽  
Atr Spectroscopy ◽  
Time Required

Thanks to what has been achieved by Fourier transformation, infrared analysis can now become a state-of-the-art device in quality control laboratories if we consider its precision and the gain in time it ensures. Moreover, an increasing number of new mathematical regression methods such as partial least-squares (PLS) regression allow multicomponent quantitative analysis in mixtures. Nevertheless, the efficiency of infrared spectrometry as a quantitative analytical method often depends on the choice of an adequate presentation for the sample. For quantitative analysis of powders, sampling appears difficult in the mid-IR. We have developed a method built on three advantages: the rapidity of Fourier transform spectroscopy, fast solvent elimination, and good peak resolution. For enhancing peak intensity on attenuated total reflectance (ATR) spectroscopy we use nondissolving and evaporating liquids. For instance, the analysis of three components (glucose, fructose, and sucrose) can be done with a precision in the range of 4%, whereas the time required to obtain an analysis report is about 5 min.

Small Molecule Diffusion and Solubility in Adhesives Used for Transdermal Drug Delivery: Infrared-Attenuated Total Reflectance (IR-ATR) Studies.

2000 ◽  
Vol 662 ◽  
Author(s):  
Adam S. Cantor
Keyword(s):  
Drug Delivery ◽  
Small Molecule ◽  
Diffusion Coefficients ◽  
Transdermal Drug Delivery ◽  
Attenuated Total Reflectance ◽  
Transdermal Drug Delivery System ◽  
Total Reflectance ◽  
Adhesive Matrix ◽  
Atr Spectroscopy ◽  
Receptor Layer

AbstractA key factor in designing a drug-in-adhesive transdermal drug delivery system is to understand the rate at which the drug and small-molecule excipients can diffuse in the adhesive matrix. The solubility of these components in the adhesive matrix is also of great importance. Results will be presented discussing the use of infrared-attenuated total reflectance (IR-ATR) spectroscopy as a method to measure both diffusion and solubility of small molecules in adhesives. In this method, the donor layer is either a doped adhesive or a free liquid that is placed in contact with a receptor layer which is an undoped adhesive in contact with an IR-ATR crystal. The IR-ATR crystal detects as a function of time any molecules that diffuse from the donor layer into and through the receptor layer.Examples will be discussed of several different experiments that can be performed with this technique. Diffusion coefficients are presented here for testosterone and terpineol in an isooctyl acrylate based adhesive using a doped adhesive donor layer. Diffusion and solubility of liquids in several adhesives has been determined using the experiment where a free liquid is used as the donor. Solubility and diffusion coefficients determined using an oversaturated doped layer containing dispersed, as well as dissolved solute, are presented here for testosterone and for progesterone. Finally diffusion from a doped layer of one adhesive to an undoped layer of a different adhesive was performed as a partition measurement. The parameters that can be extracted from each of these experiments, as well as the limitations of each type of experiment will be discussed.

In situ determination of Brønsted/Lewis acidity on cation-exchanged clay mineral surfaces by ATR-IR

Clay Minerals ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 513-522 ◽  
Author(s):  
J. Billingham ◽  
C. Breen ◽  
J. Yarwood
Keyword(s):  
Acid Sites ◽  
Lewis Acidity ◽  
Attenuated Total Reflectance ◽  
Mineral Surfaces ◽  
Lewis Acid Sites ◽  
Absorption Bands ◽  
Total Reflectance ◽  
Liquid Benzene

AbstractAttenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy has been used to determine the nature of acid sites present in Na+-, Ni2+- and Al3+-exchanged montmorillonite using the diagnostic base, pyridine. The pyridine additions were performed in situ at 25°C in the presence of liquid benzene or deuterated 1,4-dioxan to ascertain whether the acidity profile was influenced by the presence of either the non-polar or oxygenated solvent. Pyridine treated Ni2+-montmorillonite exhibited absorption bands characteristic of Lewis bound base in both benzene and deuterated 1,4-dioxan indicating that the Lewis acid sites were present at low temperature and were accessible in both solvents. The presence of a strong 1537 cm−1 band in pyridine-saturated Al3+-montmorillonite confirmed that this clay acted as a Brønsted acid in benzene. However, this diagnostic band was significantly reduced in the presence of deuterated 1,4-dioxan.

Sign in / Sign up

Export Citation Format

Share Document