Near-Infrared Spectroscopy: Principles, Instruments, Applications

About Near-Infrared Spectroscopy: Principles, Instruments, Applications detail
Amazon Sales Rank: #1579667 in Books
Published on: 2002-03-19
Original language: English
Number of items: 1
Binding: Hardcover
361 pages

Product Description
Over the last few years, near-infrared (NIR) spectroscopy has rapidly developed into an important and extremely useful method of analysis. In fact, for certain research areas and applications, ranging from material science via chemistry to life sciences, it has become an indispensable tool because this fast and cost-effective type of spectroscopy provides qualitative and quantitative information not available from any other technique.This book offers a balanced overview of the fundamental theory and instrumentation of NIR spectroscopy, introducing the material in a readily comprehensible manner. A considerable part of the text is dedicated to practical applications, including sample preparation and investigations of polymers, textiles, drugs, food and animal feed. However, special topics, such as two-dimensional correlation analysis, are also covered in separate chapters. Written by eight experts in different fields, this book presents an introduction to the current state of developments and is valuable to spectroscopists and to practitioners applying NIR spectroscopy as a daily analytical tool.

Reconstruction of constitutent spectra from near infrared sample spectra using principal components

Principal component weights are combined with regression coefficients to produce a form of spectral reconstruction which exhibits characteristics similar to the spectrum of a specific constituent. The technique is illustrated by two sets of near infrared spectra, the first consisting of wheat flour samples for which moisture and protein values were available and the second consisting of ground rapeseed meal for which oil and protein values were present. The reconstructed spectrum for water was based mainly on the second wheat flour component, which itself closely resembled the spectrum of water. The reconstructed oil spectrum matched closely the spectrum of a sample of oil extracted from the rape meal. It was not possible to extract protein from either set of samples in order to obtain a spectrum with which to compare the reconstructed spectra. However, most of the absorbance bands known to relate to proteins were present in both reconstructions, although the relative sizes of these bands differed.

A chemometrics approach for distinguishing between beers using near infrared spectroscopy

Thirty-eight beers from different producing areas and/or makers were distinguished by principal component analysis (PCA) of the near infrared (NIR) spectra acquired by a portable NIR spectrometer. Classsification of Akita beers: beers locally produced in Akita prefecture, Japan, from other famous brand beers could be successfully performed, especially when the PCA was calculated on the standard normal variate (SNV) spectra. The classification equations use information related to water and CH₂ absorption that reflected the differences in chemical composition of beers due to different production processes. In addition, the compositions of total polyphenol and total nitrogen were estimated from NIR spectra by multiple linear regression (MLR). This study showed that NIR spectroscopy is promising for beer quality evaluation, both for identifying multifarious beers including Akita beers using PCA and for rapid in-line quality control and inspection for beer production using the quantitative MLR analysis.

Infrared Thermometer

Shop infrared thermometer

Pearl Holding Tweezers

Fisherbrand Magnetic Micro Stirring Bars; Diameter Fisherbrand Magnetic Micro Stirring Bars

Stainless Steel 316L Welded Annealed Tubing

Polycarbonate Tubing

Zeus PTFE (Teflon) Regular Wall Tubing

Application of two-dimensional near-infrared (2D-NIR) correlation spectroscopy to the discrimination of three species of Dendrobium

The objective of this paper was to apply two-dimensional (2D) near-infrared (NIR) correlation spectroscopy to the discrimination of three species of Dendrobium. Generalized 2D-NIR correlation spectroscopy was able to enhance spectral resolution, simplify the spectrum with overlapped bands and provide information about temperature-induced spectral intensity variations that was hard to obtain from one-dimensional NIR spectroscopy. The FT-NIR spectra were measured over a temperature range of 30-140°C. The 2D synchronous and asynchronous spectra showed remarkable differences within the range of 5600-4750 cm^-1 between different species of Dendrobium. Copyright © 2009 John Wiley & Sons, Ltd.

Comparing the limiting resolution of the Cary 5000 and Cary 6000i UV-Vis-NIR spectrophotometers using the transmission spectrum of water vapor

Introduction

The NIR spectra of many gases and solids exhibit narrow bands containing vibrational fine structure. Resolving these peaks, which are on the order of <>

Theory

The resolving power of an absorption spectrophotometer depends on a number of different mechanical instrument parameters. These include the grating resolution (lines per mm), focal length of the monochromator, the minimum slit width and the minimum stepping interval. These parameters, along with the detector sensitivity across the wavelength range of interest, dictate the minimum resolution. A common, but incorrect, assumption often made is that the minimum resolution is only dependent on the spectral band width. If there are not enough data points collected, or the signal-to-noise (S/N) is extremely low, then the fine spectral characteristics of the sample will not be resolved.

To resolve a peak, it is a general requirement to set the SBW to 1/3rd the natural peak width, and the data interval to 1/10th the natural peak width. However, the narrower the SBW setting, the lower the amount of light hitting the detector, hence, the sensitivity of the detector becomes a very important factor if good S/N spectra are to be collected. Varian’s high performance spectrophotometers can measure the most demanding samples and the release of the new generation Cary 5000 and Cary 6000i UV-Vis-NIR absorption spectrophotometers has raised the bar to a new level. In theory, the Cary 6000i can resolve a peak of between 0.06 – 0.1 nm natural bandwidth in a relatively short time. Without a doubt, the new generation Cary range are the best UV-Vis-NIR instruments available on the market today.

Discussion

The difference between the Cary 5000 and 6000i is the minimum resolution and sensitivity. As mentioned earlier, the narrower the SBW setting, the less light hits the detector, which results in poorer S/N or requires a much longer averaging time. The Cary 6000i has a minimum SBW of 0.02 nm and uses an InGaAs detector, which has approximately 100 times greater sensitivity than the traditional PbS detectors used in most NIR measurements. This is evident in Figure 2, where signal averaging of only two seconds was required to achieve excellent S/N compared to the Cary 5000 instrument using ten seconds signal averaging time, as shown in Figure 1. Also, the SBW setting on the Cary 5000 was 0.05 nm compared to 0.02 nm on the Cary 6000i. This difference in resolution results in the peak at 1380 nm being better resolved into a doublet on the 6000i compared to the 5000, as shown in Figure 3. For comparison, this 1380 nm peak cannot be resolved into a doublet on other UV-Vis-NIR absorption spectrophotometers.

Conclusion

The Cary 5000 and 6000i instruments are by far the best spectrophotometers on the market today if high sensitivity and fine spectral resolution are required. Both instruments can resolve a peak of <0.5 nm bandwidth, with the additional sensitivity of the Cary 6000i InGaAs detector providing an order of magnitude increase in speed and throughput. Both instruments have provided new technology that will benefit customers in all areas of research.

Moisture Determination

Optical Process Probe integrates sapphire window.

Transmission probe SWOPP03C has polished sapphire lens sealed into 316 stainless steel body, offering chemically inert, abrasion-resistant interface to material under test. Along with 2,040°C melting point and 0.17-5.5 micron optical transmission range, sapphire is trigonal crystal of aluminum oxide that has Young's Modulus of 330 GPa and shear modulus of circa 150 GPa. Probe comes with 600 micron internal glass fiber and permits measurements at pressures to 10,000 psi and 400°C.

Spectroscopy

When a sample is illuminated with broad-band white light some of this energy may absorbed at discrete wavelengths by constituent molecules. The measured deficiencies in exiting energies can provide the identifying 'finger print' of the constituent molecule. In the NIR region the observed absorption bands are either overtones or combinations of overtones of fundamental bands originating in the mid infrared region (2500 to 25000 nm).

These overtones and combination bands are much weaker (typically by a factor 1000) than their counterparts in the IR region and characteristically have broad bandwidths ">(typically 30-40 nm FWHM). Low absorptivity in the NIR allows the use of long path lengths and making for minimal or no sample preparation; a significant advantage for in-line analyses.

Some typical spectra show the need to use chemometrics.

Figure 2: Typical IR Spectrum

Figure 3: Typical NIR Fruit Spectrum

source: http://pelm.cqu.edu.au/FCWViewer/view.do;jsessionid=8a4d179b30da84c6ab46b542410c940ff362ffd0c654.e34MaxeRbhuObi0LahqPa3qQc3z0n6jAmljGr5XDqQLvpAe?page=6109

The potential role of near infra red reflectance (NIR) monitoring in precision agriculture (PAG).

The adoption of precision agriculture technologies is probably one of the greatest challenges and opportunities of the 21st century to expand the horizons of soil and plant analysis by matching the spatial variability of soil properties and crop demand with a variable input of agro-resources in the field. The high cost of soil sampling and chemical and physical analysis by conventional laboratories has restricted the full implementation of this technique at field level. Near Infra Red (NIR) analysis could be a cost-effective solution, but a whole paradigm shift in philosophy is needed to move away from the traditional approach in soil testing of taking a 'perceived' representative sample in which all the spatial variation is lost, to using a combination of grid soil sampling at a sample intensity of 4 to 10 cores per ha, in which the sub samples are analysed separately using rapid but less accurate methods such as NIR. Agricultural industries worldwide are showing increasing interest in the potential applications of near infrared (NIR) analysis in the fields of soil fertility, cane nutrition, cane quality testing and screening for resistance to certain pests and diseases. Recent investigations in the sugar and wheat industries have demonstrated the feasibility of using NIR scanning techniques for mapping spatial variability of important soil properties on a field scale. Soil properties that have been calibrated include gravimetric soil water, clay, buffer capacity, pH, electrical conductivity, titratable acidity, organic matter, mineralizable nitrogen, potential ammonia volatilization from urea, potential nitrification rate, and urease activity. Mapping spatial variability in this way will enable better utilization of resources such as the application of fertilizers.

source: http://www.cababstractsplus.org/google/abstract.asp?AcNo=20053159362

ATR Accessory enables polarized measurements in FT-IR.

Combining infrared spectroscopy with polarizer, Universal Attenuated Total Reflection (ATR) Polarization Accessory provides polarized measurements, which offer additional information on molecular structure of sample and help characterize materials. Accessory is particularly suited for crystal structure analysis, polymer and fiber orientation studies, and structural analysis studies of biomolecules. Variable angle polarizer can be removed for non-polarized measurements.

source: http://news.thomasnet.com/fullstory/549568

Portable NIR Food Analyzer Kit

Analyze protein, oil, and moisture content on site!
◗ Displays results in less than one minute
Enhance the profitability of your grains and dairy products by ensuring their optimum protein, oil, and
moisture contents. Analyzer is designed for rugged use—take with you on the plant floor or in the field.
Meter analyzes protein and oil both on an “as-is” basis and a constant moisture (CM) basis. Simply pour
sample into sample holder and place holder into the meter. Results are displayed in less than one minute.
Download data to your 486 computer or better with the included calibration software and RS-232 cable.
Factory-set calibrations for HRS, HRW, protein and moisture in SWW, durum wheat, SRW,
2 row barley, 6 row barley, oats, corn, soybean, canola, mustard, flax, milo, or long-and medium-grain
rough rice. Oil calibration is included with corn, soybean, canola, mustard, and flax calibrations.

NIR Spectrometer covers 190-1,100 nm spectral range

Back thinned CCD UV-to-Near-IR spectrometer offers 2 nm (FWHM) spectral resolution, ±0.5 nm wavelength accuracy, and slit width of 25 µm. It minimizes stray light with holographic aberration-corrected flat field concave grating and optimized optical bench, which reduces noise and helps improve throughput. Optical input can be supplied through SMA905 connector. Instrument is supplied with software that allows users to configure it for large dynamic range or high sensitivity operation. source: http://news.thomasnet.com/fullstory/820046

FOSS NIRSystems Launches New Web Site

FOSS NIRSystems, Inc. is proud to announce its new website for all your Near-Infrared (NIR) analyzer needs. Please visit us at www.foss-nirsystems.com for information about FOSS NIRSystems products, education services, product support, distributors and applications in the pharmaceutical, chemical and other areas.

FOSS NIRSystems, Inc. is a unit of FOSS A/S and the world's leading supplier of laboratory, at-line and process NIR solutions. FOSS NIRSystems has more than 40 years of industry experience and over 18,000 successful installations worldwide. XDS NIR analyzers can be used throughout the manufacturing processes – from raw material inspection and in-process testing to final product release.

Rudolph launches DigiPol DS saccharimeters

Rudolph Instruments has introduced the DigiPol DS series of saccharimeters, designed to meet the range of requirements for the sugar industry.

The DS Series features three models.

The DigiPol - DS 11 is suited for refined sugar testing using lead at 589nm.

The DigiPol - DS 21 is for raw sugar testing without lead using the NIR package at 880nm.

The DigiPol - DS 41 has two wavelength 589nm visible and 880nm NIR for both with and without sugar testing with automatic wavelength changeover.

DigiPol saccharimeters can be easily configured for measuring any sugar in any length cell.

The saccharimeters are supported by Rudolph Instruments with a range of accessories, and services including sample cells, calibration standards, and calibration services.