Search results for "Fourier transform spectroscopy"
showing 10 items of 79 documents
Mid-infrared and Raman spectrometry for quality control of pesticide formulations
2005
This article deals with recent developments in the use of vibrational spectrometry for the quantitative analysis of active components in commercial pesticide formulations. We review the techniques, such as Fourier transform infrared (FTIR) and FT-Raman spectrometries, and measurement modes, such as stopped flow or flow injection. FTIR is being used increasingly in the determination of pesticides in agrochemical products because of its relatively short analysis time. However, FT-Raman spectrometry provides direct analysis of solid and aqueous samples. It is therefore clear that these techniques enable fast, non-destructive, precise and accurate measurements, so vibrational spectrometry appea…
Fourier transform infrared spectrometric determination of Malathion in pesticide formulations
2004
Abstract An environmentally friendly methodology has been developed for quality control analysis of emulsifiable concentrate pesticide formulations containing Malathion as active ingredient, using flow injection analysis (FIA)–Fourier transform infrared (FTIR) spectrometry. Five microlitres samples were directly injected into a 3 ml closed FIA manifold, in which 2 ml of CHCl 3 was re-circulated at 1.96 ml min −1 . After homogenisation and sample measurement, 2 μl volumes of a Malathion standard were injected, taking absorbance measurements after each injection. Peak height of the chemigrams, established from peak area values between 1027 and 1017 cm −1 , corrected with a baseline fixed from…
Determination of insolubles in diesel lubricating oil by FIA-visible spectrometry
2003
Insolubles determination is one of the parameters usually recommended to evaluate the residual life of oil because their presence at elevated levels in diesel lubricating oil changes the viscosity, prematurely clogs filters and is one of the major factors in causing abrasive engine wear. The proposed method employs visible spectrophotometric detection in association with flow injection analysis. The results obtained by this method were compared with the ones obtained by Fourier transform infrared spectrometry (FT-IR) since this is the most employed method for insolubles determination. The proposed method presented a linear response from 0 to 3% (w/w) of insolubles in pentane (ASTM D-893). T…
Investigation of the hyperfine structure of weak atomic Vanadium lines by means of Fourier transform spectroscopy
2015
In continuation of our work on the investigation of the hyperfine structure (HFS) of atomic vanadium, we analyzed weak spectral lines in a Fourier transform spectrum that have not been investigated up to now. The main objective of this work was the determination of the magnetic dipole HFS constant A of the energy level at 15 103.784 cm−1, which was the only energy level with unknown A value up to the energy of 28 000 cm−1. Additionally, other gaps in the data of magnetic dipole HFS could be filled in. The spectrum of vanadium–argon plasma in a hollow cathode lamp is recorded in the spectral range from 12 500 to 26 000 cm−1 or 800 to 380 nm, respectively. The HFS of 42 weak atomic vanadium l…
High-Resolution Spectroscopy and Preliminary Global Analysis of C–H Stretching Vibrations of C2H4 in the 3000 and 6000 cm-1 Regions
2010
International audience; Ethylene (ethene, H2C=CH2) is a naturally occurring compound in ambient air that affects atmospheric chemistry and global climate. The C2H4 spectrum is available in databases only for the 1000 and 3000 cm−1 ranges. In this work, the ethylene absorption spectrum was measured in the 6030- 6250 cm−1 range with the use of a high resolution Bruker IFS 125HR Fourierspectrometer and a two-channel opto-acoustic spectrometer with a diode laser. As a secondary standard of wavelengths, the methane absorption spectrum was used in both cases. A preliminary analysis was realized thanks to the tensorial formalism developed by the Dijon group that is implemented in the XTDS software…
Hybrid magnetic materials formed by ferritin intercalated into a layered double hydroxide
2008
A hybrid magnetic material formed by ferritin intercalated into a layered double hydroxide (LDH) of Mg and Al (Mg/Al molar ratio 2) is prepared and characterized through powder X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR) spectroscopy, electron probe microanalysis (EPMA) and high resolution transmission electron microscopy (HRTEM). One observes an enhancement in the thermal stability of the ferritin molecules when they are inserted in the layered material. Magnetic measurements of the hybrid material exhibit the typical superparamagnetic behaviour of the ferritin molecule. On the other hand, the intercalation of ferritin into the LDH guarante…
Infrared absorption study of hexapentyloxytriphenylene A discotic liquid crystal
1993
Abstract Fourier transform infrared absorption (FTIR) spectroscopy has been used to study a discotic liquid crystal. IR spectra are reported as a function of temperature for hexapentyloxytriphenyle...
Study of the v3 = 1 State of 80SeF6 by Fourier Transform Spectroscopy
1997
The Fourier transform infrared spectrum of monoisotopic 80SeF6 has been recorded in the 760-792 cm-1 region with an effective resolution of ca. 2.3 x 10(-3) cm-1. The 80SeF6 sample was prepared by burning monoisotopic 80Se powder (99.2%) in an excess of fluorine. The analysis of infrared transitions of the nu3 band enabled the determination of parameters of the Hamiltonian developed up to the third order and the fourth order. The standard deviation obtained is equal to 4 x 10(-4) cm-1 for the third-order development and 3.2 x 10(-4) cm-1 for the fourth-order development. In the two analyses, 2900 lines were assigned and fitted. Copyright 1997 Academic Press. Copyright 1997Academic Press
Microwave Fourier Transform Spectroscopy of Rovibrational Transitions in the ν 2 /ν 4 Dyads of Methane- 12 C and - 13 C
1987
The ν2/ν4 dyad-dyad spectra of 12CH4 and 13CH4 molecules in the (8÷20) GHz region have been predicted including line strengths. All transitions with γmax > 810-12 cm-1 have been observed directly using a MWFT spectrometer: six F-type transitions for 12CH4 and nine for 13CH4.
Crystal growth of Hg1−xMnxSe for infrared detection
2007
In this work, we report on the successfully growing Hg"1"-"xMn"xSe bulk crystals using a mixed, travelling heater method and Bridgman method, two-step procedure. Firstly, and with the aim of reducing Hg high pressure related to the high temperature synthesis reaction between the components in elemental form, HgSe crystals were synthesized and grown by the cold travelling heater method. Secondly, previously sublimated Mn and Se were incorporated to complete the desired composition. Then, the Bridgman growth was carried out by heating the alloy at a temperature of about 880^oC and lowering it at rate of 1mm/h through a gradient of 25^oC/cm. The Hg"1"-"xMn"xSe crystals were characterized by sc…