The theory and instrumentation for Fourier transform infrared spectrometry are discussed. These instruments measure infrared spectra of the same quality as spectra measured on grating spectrometers in about one thousandth of the time. Their sensitivity advantage for spectra measured in equal times is between a factor of 10 and 100. Commercial spectrometers are now available from nine vendors in North America. Important areas of chemistry include atmospheric monitoring, surface chemistry, and on-line identification of chromatographically separated materials. Many new biochemical and biomedical applications are also becoming apparent, including investigations of phase transitions in lipids and studies of the biocompatibility of implant polymers.

https://science.sciencemag.org/content/sci/222/4621/297.full.pdf

Fourier Transform Infrared Spectrometry

This paper reviews the theory and applications of photoacoustic (also called optoacoustic) methods belonging to the more general area of photothermal measurement techniques. The theory covers excitation of gaseous or condensed samples with modulated continuous light beams or pulsed light beams. The applications of photoacoustic methods include spectroscopy, monitoring deexcitation processes, probing physical properties of materials, and generating mechanical motions. Several other related photothermal methods, as well as particle-acoustics and wave-acoustics methods are also described. This review complements an earlier and narrower review [Rev. Mod. Phys. 53, 517 (1981)] that is mainly concerned with sensitive detection by pulsed photoacoustic spectroscopy in condensed matter.

Applications of photoacoustic sensing techniques

http://www.css.cornell.edu/faculty/lehmann/publ/OrgGeochem%2037,%201477-1488,%202006%20Cheng%20www.pdf

Oxidation of Black Carbon by Biotic and Abiotic Processes

Pyrogenic or “black” carbon is a soil and sediment component that may control pollutant migration. Biochar, black carbon made intentionally by biomass pyrolysis, is increasingly discussed as a possible soil amendment to increase fertility and sequester carbon. Though thought to be extremely refractory, it must degrade at some rate. Better understanding of the rates and factors controlling its remineralization in the environment is needed. Release of CO2 was measured over 1 year from microbial and sterile incubations of biochars made from a range of biomass types and combustion conditions. Carbon release from abiotic incubations was 50−90% that of microbially inoculated incubations, and both generally decreased with increasing charring temperature. All biochars displayed log−linearly decreasing mineralization rates that, when modeled, were used to calculate 100 year C losses of 3−26% and biochar C half-lives on orders ranging from 102 to 107 years. Because biochar lability was found to be strongly controll...

/pdf/abiotic-and-microbial-oxidation-of-laboratory-produced-black-4tj2tfiycn.pdf

Abiotic and microbial oxidation of laboratory-produced black carbon (biochar).

Chemical modification of silica surface by immobilization of functional groups for extractive concentration of metal ions.

Infrared photoacoustic spectra were recorded over the 3900 to 1400 cm-1 range with a single-beam, computer-controlled spectrometer fitted with a broad-band source and LiF and CaF2 prisms. The exploratory results indicate that structured IR spectra of organic solids can be obtained. Various surface treatments were used to alter the chemical composition of the surfaces of samples composed of thick catalyst pellets and of thick beds of powdered silica and alumina, under controlled conditions in a reactor attached to the acoustic cell. The IR bands of resulting surface species were observable at sub-monolayer coverages. With some improvements, IR-photoacoustic spectroscopy will be a useful ancillary technique especially suited for studying surface species on thick adsorbents, catalysts, and corrosion layers.

Infrared Photoacoustic Spectroscopy of Solids and Surface Species

Since what appears to be the first infrared (IR) observation of a char by Kmetko in 1951,1 IR spectra of coals, chars and various carbon materials have been invariably shown to have a more or less intense band near 1600 cm−1 A variety of suggestions has been made concerning the cause of the band but the assignments have been in dispute and remained controversial for thirty years

M.J.D. Low

Papers

Infrared Photoacoustic Spectroscopy of Solids and Surface Species

The Nature of the 1600 cm−1 Band of Carbons

IR studies of carbons—III: The oxidation of cellulose chars

An infrared photothermal beam deflection fourier transform spectrometer

Infrared photothermal deflection spectroscopy for the study of surfaces