EXPRESS: Detection and Identification of Wolbachia pipientis Strains in Mosquito Eggs Using Attenuated Total Reflection Fourier Transform Infrared (ATR FT-IR) Spectroscopy

2021 ◽  
pp. 000370282110271
Author(s):  
Dale Christensen ◽  
Aazam Khoshmanesh ◽  
David Perez-Guaita ◽  
Inaki Iturbe-Ormaetxe ◽  
Scott O'Neill ◽  
...  
Keyword(s):  
Wolbachia Infection ◽  
Target Population ◽  
Attenuated Total Reflection ◽  
Classification Error ◽  
Wolbachia Pipientis ◽  
Detection And Identification ◽  
Sensitivity And Selectivity ◽  
Ft Ir ◽  
Key Driver ◽  
Ft Ir Spectroscopy

The global fight against mosquito-borne viral diseases has in recent years been bolstered by the introduction of the endosymbiotic bacteria Wolbachia to vector populations, which in host mosquitoes supresses the transmissibility of several viruses. Researchers engaged on this front of the battle often need to know the Wolbachia infection status of individual mosquitoes as the intervention progresses and the mosquitoes become established in the target population. Previously we have successfully applied ATR-FTIR spectroscopy to the detection of Wolbachia in adult <i>Aedes aegypti</i> mosquitoes; here we apply the same principles to Aedes eggs, with sensitivity and selectivity > 0.95. Further, we successfully distinguish between infections in eggs of the wMel and wMelPop strains of <i>Wolbachia pipientis</i>, with a classification error of 3%. The disruption of host lipid profile by Wolbachia is found to be a key driver in spectral differences between these sample classes.

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

Foods ◽  
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.

Spectroscopic Investigations on the Depth-Dependent Degradation Gradients of Aged Triterpenoid Varnishes

2007 ◽  
Vol 61 (10) ◽  
pp. 1045-1051 ◽  
Author(s):  
Charis Theodorakopoulos ◽  
Vassilis Zafiropulos ◽  
Jaap J. Boon ◽  
Stamatis C. Boyatzis
Keyword(s):  
Structural Modification ◽  
Attenuated Total Reflection ◽  
Vibration Modes ◽  
Bending Vibration ◽  
Depth Profiles ◽  
Excimer Laser Ablation ◽  
Natural Resin ◽  
Ft Ir ◽  
Krf Excimer Laser ◽  
Ft Ir Spectroscopy

The depth-profiles of accelerated aged triterpenoid dammar and mastic varnishes, which had been uncovered by optimized KrF excimer laser ablation (248 nm, 25 ns), were examined by ultraviolet–visible (UV/VIS) spectrophotometry and attenuated total reflection (ATR) Fourier transform infrared (FT-IR) spectroscopy. The results reflect both the optical properties at the bulk (UV/VIS) and the surface (ATR/FT-IR) and establish the presence of degradation gradients across the depth of the degraded natural resin films. It is demonstrated that the UV part of the ambient radiation is absorbed by the deteriorated surface and that the optical densities of the aged varnish decrease as a function of depth. The absorbed UV wavelengths at the surface and the depth-wise reduction of light intensity result in a depth-dependent decrease in carbonyl absorbance and an increase in C–H bending vibration modes of methylene species pointing to structural modification in the triterpenoid mixture across depth.

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

1987 ◽  
Vol 41 (7) ◽  
pp. 1172-1175 ◽  
Author(s):  
Gi Xue ◽  
Shi-Ying Liu ◽  
Yi Jin ◽  
Shan-Geng Jiang
Keyword(s):  
Diffuse Reflectance ◽  
Collection Efficiency ◽  
Scattered Light ◽  
Attenuated Total Reflection ◽  
Light Collection ◽  
Wire Sample ◽  
Ft Ir ◽  
Metal Wires ◽  
Ft Ir 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.

Quantitative ATR FT-IR Analysis of Surface Segregation of Polymer Blends of Polystyrene/Poly(Dimethylsiloxane)-co-polystyrene

1998 ◽  
Vol 52 (3) ◽  
pp. 361-366 ◽  
Author(s):  
Jiaxing Chen ◽  
Joseph A. Gardella
Keyword(s):  
Polymer Blends ◽  
Penetration Depth ◽  
Surface Segregation ◽  
Calibration Procedure ◽  
Attenuated Total Reflection ◽  
Depth Dependence ◽  
Quantitative Surface Analysis ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

The surface segregation of a series of two-component polymer blends of polystyrene/poly(dimethylsiloxane)-co-polystyrene has been studied by attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy. We examined the details of calibration for quantitative ATR FT-IR. The quantitation is based on calibration of Beer's law by transmission FT-IR measurements. The effect of spectral distortion and penetration depth dependence of radiation wavelength due to ATR sampling is evaluated. ATR spectra are corrected for penetration depth dependence before being used for quantitation. The corrected ATR spectra were compared with the transmission spectra of the same samples. Peak area ratios using one peak from each component were measured for the determination of the concentration of surface poly(dimethylsiloxane). The correction and calibration procedure improves the accuracy of quantitative surface analysis in the range of micrometer sampling depth. Unlike other approaches for quantification of ATR data on polymers, this method can be used for systems with a complex, unknown concentration gradient near the surface such as the blend system reported here.

scholarly journals Electrospray Film Deposition for Solvent-Elimination Infrared Spectroscopy

2019 ◽  
Vol 73 (6) ◽  
pp. 638-652
Author(s):  
Andrea Arangio ◽  
Christophe Delval ◽  
Giulia Ruggeri ◽  
Nikunj Dudani ◽  
Amir Yazdani ◽  
...  
Keyword(s):  
Inorganic Compounds ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Film Deposition ◽  
Multiple Reflections ◽  
Solution Composition ◽  
Upper Limit ◽  
Volatile Organic ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

The application of electrospray (ES) for quantitative transfer of analytes from solution to an internal reflection element for analysis by attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy has been developed in this work. The ES ATR FT-IR method is evaluated with non-volatile and semi-volatile organic and inorganic compounds dissolved in pure organic solvents or organics in a mixture with water. The technique demonstrates the capability for rapid solvent evaporation from dilute solutions, facilitating the creation of thin films that allow ATR FT-IR to generate transmission-mode-like spectra. Electrospray ATR FT-IR with multiple reflections displays a linear response ( R2 = 0.95–0.99) in absorbance with the deposited mass and instrumental detection limit < 100 ng, which demonstrates potential for quantitative applications. The method is applicable when crystalline substances are present, even though the formation of particles restricts the upper limit of mass loadings relative to substances forming homogeneous films. In addition to the solvent, semi-volatile compounds can evaporate during the ES process; the magnitude of losses will depend on solution composition and temperature.

Attenuated Total Reflection (ATR) Micro-Fourier Transform Infrared (Micro-FT-IR) Spectroscopy to Enhance Repeatability and Reproducibility of Spectra Derived from Single Specimen Organic-Walled Dinoflagellate Cysts

2021 ◽  
pp. 000370282110411
Author(s):  
Pjotr Meyvisch ◽  
Pieter R. Gurdebeke ◽  
Henk Vrielinck ◽  
Kenneth Neil Mertens ◽  
Gerard Versteegh ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Fourier Transform Infrared ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Data Sets ◽  
Systematic Exploration ◽  
Ft Ir ◽  
Repeatability And Reproducibility ◽  
Processing Steps ◽  
Ft Ir Spectroscopy

The chemical composition of recent and fossil organic-walled dinoflagellate cyst walls and its diversity is poorly understood and analyses on single microscopic specimens are rare. A series of infrared spectroscopic experiments resulted in the proposition of a standardized attenuated total reflection micro-Fourier transform infrared-based method that allows the collection of robust data sets consisting of spectra from individual dinocysts. These data sets are largely devoid of nonchemical artifacts inherent to other infrared spectrochemical methods, which have typically been used to study similar specimens in the past. The influence of sample preparation, specimen morphology and size and spectral data processing steps is also assessed within this methodological framework. As a result, several guidelines are proposed which facilitate the collection and qualitative interpretation of highly reproducible and repeatable spectrochemical data. These, in turn, pave the way for a systematic exploration of dinocyst chemistry and its assessment as a chemotaxonomical tool or proxy.

Shape-controlled synthesis of CO-free Pd nanocrystals with the use of formic acid as a reducing agent

2016 ◽  
Vol 52 (85) ◽  
pp. 12594-12597 ◽  
Author(s):  
Shixiong Bao ◽  
Xuan Yang ◽  
Ming Luo ◽  
Shan Zhou ◽  
Xue Wang ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Formic Acid ◽  
Reducing Agent ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Controlled Synthesis ◽  
Ft Ir ◽  
Shape Controlled ◽  
No Chemisorption ◽  
Ft Ir Spectroscopy

This paper reports the use of formic acid as a reducing agent for the shape-controlled synthesis of Pd nanocrystals with no chemisorption of CO on the surface, as confirmed by attenuated total reflection Fourier transform infrared (ATR-FT-IR) spectroscopy.

Sign in / Sign up

Export Citation Format

Share Document