Infrared Microsampling by Diffuse Reflectance Fourier Transform Spectrometry

1980 ◽  
Vol 34 (5) ◽  
pp. 533-539 ◽  
Author(s):  
Michael P. Fuller ◽  
Peter R. Griffiths
Keyword(s):  
Fourier Transform ◽  
Thin Layer ◽  
Diffuse Reflectance ◽  
Absorption Bands ◽  
Fourier Transform Spectrometry ◽  
Increased Sensitivity ◽  
Intense Absorption ◽  
Diffuse Reflectance Infrared ◽  
Layer Chromatography

It is shown that diffuse reflectance techniques enable increased sensitivity to be obtained for infrared microsampling compared with the use of KBr micropellets. When nonabsorbing matrices, such as KCl, are used, detection limits of less than 10 ng of samples are observed. Samples absorbed on graphitized substrates, which have a fairly strong general absorption but few intense absorption bands, may also be studied but at somewhat reduced sensitivity. Diffuse reflectance infrared Fourier transform spectrometry does not appear to be particularly useful for studying adsorbates on silica gel, which is not only a strong infrared absorber but also has a surface which is so active that small changes in the surface structure can change the spectrum significantly. Extraction of sample spots from thin layer chromatography plates followed by deposition onto KCl yields much better results than in situ measurements.

Microchannel Thin Layer Chromatography with in situ Plate Scanning Micro-DRIFTS Detection Using Plain and Polybutadiene Modified Zirconia Stationary Phases

2002 ◽  
Vol 56 (8) ◽  
pp. 1059-1066 ◽  
Author(s):  
Beata A. Musial ◽  
André J. Sommer ◽  
Neil D. Danielson
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Diffuse Reflectance ◽  
Stationary Phases ◽  
Reversed Phase ◽  
Diffuse Reflectance Infrared ◽  
Layer Chromatography ◽  
Tlc Separation ◽  
Zirconia Stationary Phases

Thin layer chromatography (TLC) of various dyes is compared in microchannels packed with either bare zirconia (normal phase) or polybutadiene (PBD) modified zirconia (reversed phase). In situ micro-diffuse reflectance infrared Fourier transform spectroscopy (μDRIFTS) of the analyte spots is possible due to the low absorption background of both plain and PBD zirconia. An instrument coupling μDRIFTS with a motorized stage that could profile the microchannel TLC plate is developed. The retention order of anthracene and pyrene probes as a function of percent acetonitrile are generally as expected on PBD zirconia but opposite for plain zirconia. Impurities in technical grade methylene blue can be determined after TLC separation on plain zirconia. The separation and infrared identification of various dyes such as dichlorofluorescein and rhodamine B on PBD zirconia is improved using a mobile phase with an additive such as phosphate or dihexylamine that prevents band streaking.

scholarly journals Development of a diffuse reflectance infrared fourier transform spectroscopy (DRIFTS) cell for the in situ analysis of co-electrolysis in a solid oxide cell

2015 ◽  
Vol 182 ◽  
pp. 97-111 ◽  
Author(s):  
Denis J. Cumming ◽  
Christopher Tumilson ◽  
S. F. Rebecca Taylor ◽  
Sarayute Chansai ◽  
Ann V. Call ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Diffuse Reflectance ◽  
Fourier Transform Spectroscopy ◽  
Transport Processes ◽  
Solid Oxide ◽  
Electrochemical Measurements ◽  
Ex Situ ◽  
Diffuse Reflectance Infrared ◽  
Solid Oxide Cell

Co-electrolysis of carbon dioxide and steam has been shown to be an efficient way to produce syngas, however further optimisation requires detailed understanding of the complex reactions, transport processes and degradation mechanisms occurring in the solid oxide cell (SOC) during operation. Whilst electrochemical measurements are currently conducted in situ, many analytical techniques can only be used ex situ and may even be destructive to the cell (e.g. SEM imaging of the microstructure). In order to fully understand and characterise co-electrolysis, in situ monitoring of the reactants, products and SOC is necessary. Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) is ideal for in situ monitoring of co-electrolysis as both gaseous and adsorbed CO and CO2 species can be detected, however it has previously not been used for this purpose. The challenges of designing an experimental rig which allows optical access alongside electrochemical measurements at high temperature and operates in a dual atmosphere are discussed. The rig developed has thus far been used for symmetric cell testing at temperatures from 450 °C to 600 °C. Under a CO atmosphere, significant changes in spectra were observed even over a simple Au|10Sc1CeSZ|Au SOC. The changes relate to a combination of CO oxidation, the water gas shift reaction, carbonate formation and decomposition processes, with the dominant process being both potential and temperature dependent.

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