Reflectance spectrometry

From the beginning of the 1980s, some effective experimental approaches based on new principles have been invented for the study of interfacial reactions in solvent extraction chemistry. Recently, some methods were developed from our laboratory, the highspeed stirring (HSS) method [4,5], the two-phase stopped flow method [6], the capillary plate method [7], the reflection spectrometry [8], and the centrifugal liquid membrane (CLM) method [9]. 

Mattson and Mark [55,56] reported some criticism of Kawahara s technique. They claim that evaporation of the solvent chloroform by infrared heating removes volatiles and causes large changes in the ratios. An oil sample was shown to suffer such alteration by the infrared during repeated analysis. The absorption of all bands decreased nonuniformly between 20 and 100% over a period of 30 min. They propose the application of internal reflection spectrometry as a rapid, direct qualitative technique requiring no sample pretreatment. 

N. J. Harrick and G. I. Loeb, Multiple internal reflection spectrometry, Anal, Chem, 45, 687-691 (1973). 

M. Blanco, J. Coello, H. Iturriaga, S. Maspoch and C. Pezuela, Strategies for constructing the calibration set in the determination of active principles in pharmaceuticals by near infrared diffuse reflectance spectrometry. Analyst, 122, 761-765 (1997). 

E. Dreassi, G. Ceramelh, P. Corti, PS. Lonardi and P. Permccio, Near-infrared reflectance spectrometry in the determination of the physical state of primary materials in pharmacentical production. Analyst, 120, 1005-1008 (1995). 

U.S.) Defense Advanced Projects Agency Dihydrolipoic acid (U.S.) Department of Defense (U.S.) Department of Energy (U.S.) Department of Transportation Differential reflectrometry = differential reflection spectrometry... 

Differential reflection spectrometry = differential reflectrometry digital signal processor Electrochemistry Electron-capture device... 

For the application of indirect calibration methods, one should have several samples available with known constitution. These samples should be of exactly the same type as the unknown sample. For example for the determination of the fat, water and protein content in wheat by near infrared reflectance spectrometry, one should have available a number of wheat flour samples of which the amount of fat, water and protein is known, or determined by a conventional method. 

Film electrodes can be conveniently prepared from numerous types of materials on a wide variety of substrates in a bewildering variety of configurations, with high purity and chemical and spatial reproducibility. Some applications rely on the convenience of preparing uniform electrochemical films on optical quality substrates for reflection spectrometry [2], or for electrodes in thin-layer cells, where flatness and parallelism of electrodes to tolerances of a few micrometers is necessary [3,4]. Film electrodes are useful for many other applications. In... 

An application of ultrasound that is becoming increasingly popular in the food industry is the determination of creaming and sedimentation profiles in emulsions and suspensions (Basaran et al., 1998). Acoustic techniques can also assess nondestructively the texture of aerated food products such as crackers and wafers. Air cells, which are critical to consumer appreciation of baked product quality, are readily probed due to their inherent compressibility (Elmehdi et al., 2003). Kulmyrzaev et al. (2000) developed an ultrasonic reflectance spectrometer to relate ultrasonic reflectance spectra to bubble characteristics of aerated foods. Experiments were carried out using foams with different bubble concentration and the results showed that ultrasonic reflectance spectrometry is sensitive to changes in bubble size and concentration of aerated foods. 

Adsorption of Proteins and Polysaccharides at Aqueous—Solid Interfaces by Infrared Internal Reflection Spectrometry In Situ Investigation... 

Anderson, M., Josefson, M., Langkilde, F., and Wahlund, K.-G. (1999), Monitoring of a film coating process for tablets using near infrared reflectance spectrometry, /. Pharm. Biomed. Anal., 20, 27-37. 

Hansen WN, Kuwana T et al (1966) Observation of electrode-solution interface by means of internal reflection spectrometry. Anal Chem 38(13) 1810-1821... 

Chaffin, N.C. Griffiths, P.R. Role of scattering coefficients in extended near-infrared diffuse reflection spectrometry. Appl. Spectrosc. 1998, 52, 218-221. 

Tor attenuated total-reflectance spectrometry. Unless otherwise indicated. 

Ni, Co, Cu TLC alumina, silica gel, cellulose Diffuse reflectance spectrometry + rubeanic acid 50 ng 231)... 

Co, Ni, Zn Cellulose Reflectance spectrometry + neocuproin or dimethyl-glyoxime pg-Range 235)... 

Se, Te Paper-chromato- graphy Minerals + SnCl2, reflectance spectrometry 10 % 238)... 

RA Lodder, GM Hieftje. Analysis of intact tablets by near-infrared reflectance spectrometry. Appl Spectrosc 42 556-558, 1988. 

The value of computing derivative spectra to correct for non-linear baseline signals is frequently exploited in reflectance spectrometry. Rapid measurement of the chemical composition of materials and products by diffuse reflectance spectroscopy in the near-infrared (NIR) region (800-2600 nm) is routine in many industries. Because most bulk materials are not transparent the mode of measurement is generally reflectance. For powder samples the intensity of... 

Light Absorption Spectrometry Light absorption spectrometry (molecular absorption) (LAS) has several names, and includes techniques such as UV/VIS (visible) spectrometry, colorimetry, flame molecular absorption, reflectance spectrometry, turbidimetry, nephelometry, ring oven technique, ion test paper and spot tests. Its colorful history and principles may be found in the older, classical books on analytical chemistry. Upor et al. (1985) have an entire volume on photometric methods in inorganic trace analysis in the respected Comprehensive Analytical Chemistry series covering interference separation and analyte concentration, preparation of samples, factors... 

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