Near infrared spectroscopy reproducibility

BOD was determined in wastewater using a microbial sensor based on an organic-inorganic hybrid material for immobilization of the biofilm. The biosensor response to the sample exhibited good reproducibility, long-term stability, and required only 10 min for each measurement.130 Near-infrared spectroscopy was used for the rapid determination of COD and BOD in wastewater.131... 

R. Kragelj, T. Jarm, and D. Miklavcic, Reproducibility of Parameters of Postocclusive Reactive Hyperemia Measured by Near-Infrared Spectroscopy and Transcutaneous Oximetry, Ann. Biomed. Eng., 28(2), 168-173 (2000). 

Figure 8.12 Near-infrared spectrum of dehydrated tomato soup. From Davies, A. M. C. and Grant, A., Near Infrared Spectroscopy for the Analysis of Specific Molecules in Food , in Analytical Applications of Spectroscopy, Greaser, C. M. and Davies, A. M. C. (Eds), pp. 46-51 (1998). Reproduced by permission of The Royal Society of Chemistry.

Figure 8.14 Near-infrared spectra of four commercial spirits (a) Scotch whiskey (40% ethanol) (b) gin (47% ethanol) (c) vodka (50% ethanol) (d) Bourbon (55% ethanol) [12], From McClure, W. F. and Stanfield, D. L., Near-Infrared Spectroscopy of Biomaterials , in Handbook of Vibrational Spectroscopy, Vol. 1, Chalmers, J. M. and Griffiths, P. R. (Eds), pp. 212-225. Copyright 2002. John Wiley Sons Limited. Reproduced with permission.

Near-infrared spectroscopy provides the client with ability to test things that could not be economically or practically tested before NIRS, because of the time and cost of testing. The technology provides the same accuracy (attainable by bias adjustment, where needed) and at least the same and usually superior reproducibility of reference methods, at a fraction of the cost, and in a fraction of the time. 

Figure 8 An online spectrum of anhydrous HCl at 30 psig. (Reproduced with permission from Tate JD, Chauvel P, Guenard RD, and Harner R (2002) Process monitoring by mid- and near-infrared Fourier transform spectroscopy. In Chalmers JM and Griffiths PR (eds.) Handbook of Vibrational Spectroscopy, vol. 4, pp. 2737-2769. Chichester Wiley John Wiley Sons Ltd.)...

Optical emission spectroscopy includes the observation of flame-, arc-, and spark-induced emission phenomena in the ultraviolet, visible, and near infrared regions of the electromagnetic spectrum [38]. Qualitative and quantitative information can be gained from the intensity of the characteristic emission wavelengths. Analysis of lead in environmental samples (e.g., soils, rocks, and minerals) may be performed reproducibly down to the 5 ppm level. Emission spectroscopy is best used for the multi-elemental analysis of samples, because of the high cost of equipment. Usually, single element analyses are not performed on a emission spectrograph. 

Infrared Photothermal Beam Deflection Spectroscopy Infrared photothermal beam deflection spectroscopy (IR-PDS) is better than PAS because it does not have a microphone near the sample. It involves two light sources. One is an interferometer that produces modulated radiations to illuminate the sample, and the other is a laser source that is placed so that its beam grazes the surface of the carbon sample. The absorption of the incident-modulated radiation beam by the sample produces heat, causing thermal gradients that deflect the laser beam. The deflected laser beam is detected by the detector, and the signal reproduced is a measure of the photothermal effect induced on the sample surface. The resulting... 

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