Spectrometers infrared

Figure 4.5 Schematic diagram of a Fourier transform infrared (FTIR) spectrometer. Infrared radiation enters from the left and strikes a beam-splitting mirror (BS) angled such that half of the beam is directed towards a fixed mirror (Mi) and half towards a moveable mirror (M2). On reflection the beam is recombined and directed through the sample towards the detector. M2 is moved in and out by fractions of a wavelength creating a phase difference between the two beam paths. This type of device is called a Michelson interferometer.

To record the infrared spectra, samples of the parent kaolinite and the three hydrates were dispersed in a fluorinated hydrocarbon. The mulls were squeezed between calcium fluoride plates and the sample was placed directly in the beam of a Perkin-Elmer 683 spectrometer. This mounting technique results in a tendency for the clay layers to align themselves perpendicular to the beam of the spectrometer. Infrared spectra of these materials have been pub-... 

Airborne tunable laser absorption spectrometer infrared absorption by tunable diode laser spectroscopy 41... 

The composites as well as the nanowires were characterized by several techniques. Scanning electron microscopy (SEM) images and energy dispersive analysis of x-rays (EDAX) were obtained with a Leica S-440I microscope fitted with a Link ISIS spectrometer. Infrared (IR) spectra were recorded on small pieces of the samples embedded in KBr pellets using a Broker FT-IR spectrometer. DSC was carried out on the samples ( 7 mg) with a scanning rate of 20 K min-1 between 120 and 260 °C using a Mettler-Toledo DSC. 

Infrared Spectrometers. Infrared spectroscopy is one of the most powerful tools for quantitative and qualitative identification of molecules, and this led to the early development of prism and grating spectrophotometers. Typically, these instruments cover the region from 400 to 4000 cm, give a resolution of 1 to 4 cm, and require calibration with polystyrene films or with standard gases such as H2O, CO2, CH4, or This al-... 

Conceive syntheses of the chosen, final, and intermediate compounds Select appropriate starting materials, reagents, reactions, and conditions Monitor the progress of reactions, employing suitable analytical methods Isolate, purify, characterize, and identify organic compounds Operate standard Items of laboratory equipment Spectrometers Infrared... 

In a typical set-up (constructed as an accessory to be mounted in the sample compartment of a commercial FT spectrometer), infrared radiation is focused on the sample surface at a defined angle. The reflected beam is focused onto a detector. Irradiation with a polarized IR beam is often used. 

Solid samples of illicit drugs can be mixed with potassium bromide and pressed into a pellet, which is then placed in the spectrometer. Infrared radiation is passed through the sample, which will absorb at characteristic energies depending on its chemical structure. The transmitted radiation is collected and the infrared spectrum is generated. Because potassium bromide does not absorb infrared radiation, the subsequent infrared spectrum shows only contributions from any drug present in the sample. 

The composition of resulting copolymers was determined by H NMR spectroscopy in CDCI3. NMR spectra were recorded on a Bruker Model MSL-300 spectrometer. Infrared (IR) spectra of the yUdes and copolymers synthesized were recorded on a Specord M-82 spectrophotometer. Differential scanning... 

Characterization. Nuclear magnetic resonance (NMR) spectra were obtained using a GE QE 300 MHz spectrometer. Infrared (IR) spectra were recorded on a Nicolet 20 SXB FTIR spectrometer. A Shimadzu UV-2401PC UV-Vis recording spectrophotometer was used to record the absorption spectra. 

The H and Si NMR data presented here were obtained in (De)DMSO (1) or CeDe (2) on a Bruker AM 250 spectrometer. Infrared spectra were recorded on a Bio-Rad FTS-7 spectrometer (Nujol mulls between KBr plates), mass spectra on Finnigan MAT 8230, and Varian MAT CHS instruments (El, 70 eV). Melting points were obtained using a Bilchi 510 or HWS-SG 300 apparams. Elemental analyses were performed by the Analytical Laboratory of the Inorganic Institute at the University of Gottingen. 

Principles and Characteristics There are many types of samples for which the transmission approach is not optimum, desirable or even practicable, e.g. urethane foams, polymer laminates, and surface coatings. To obtain spectra from these types of sample it is more usual to employ a reflection technique. Reflection measurements are often also needed when materials are to be measured in their original form, except for thin films. This essentially turns IR spectroscopy into a surface analysis technique, but of low sensitivity compared to high vacuum spectroscopic techniques such as XPS, LEFT), EELS and SIMS. Since the advent of FTIR spectrometers, infrared sensitivity has so much improved that nowadays a measurable spectrum can be produced from even a single monolayer on a flat surface interfaces are also commonly examined. 

The biggest changes that have occurred in recent years have been in instrumentation, and the chapter on IR experimental techniques has been revised extensively. We have avoided detailed descriptions of instruments rather we have described in broad terms the basic features of instrumentation. These include discussions of interferometers that are used in Fourier transform IR spectrometers, and discussions of grating monochromators that are used in dispersive IR spectrometers. Infrared spectra can be run on gases, liquids, or solids most of the techniques used in running these samples are discussed. Solid sampling techniques are the most diversified. Sections are included on quantitative analysis, internal reflection spectroscopy, and the use of polarized IR radiation. 

Freezeout with mass spectrometer, infrared and chromatograph... 

The sampling technique chosen is dependent not only on the availability of a spectrometer (infrared or Raman) and the facilities available on it, but also on the nature of the sample and the type of information required. In some instances, all that is required is confirmation that the sample is the same as that previously examined or is of a specific class of polymer, in which case a simple fingerprint may be sufficient to achieve this. 

Measurements. High performance liquid chromatography (HPLC) measurements were performed by using C18 column with a Shimadzu LC-9A and SPD-6A (UV spectrophotometric detector). Gas chromatography (GC) measurements were performed by using a OV 101 colunm with Simadzu GC-7A with a flame ionization detector. Inductively coupled plasma (ICP) spectrometric measurements were carried out by using a SII SPS1500VR plasma Spectrometer. Infrared (IR) spectra were recorded on a JASCO FTIR-8100 Fourier transform infrared spectrophotometer. NMR spectra were recorded on a JEOL FX-90Q NMR spectrometer and homo J-resolved NMR spectra and homonuclear... 

Spectrometer Device for resolving, measuring, and characterizing electromagnetic energy produced when matter changes between allowed energy levels. Examples include X-ray spectrometers, optical spectrometers, infrared spectrometers, and NMR spectrometers. 

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