Reference Materials in Extended near Infrared Diffuse Reflection Spectrometry—The Misuse of Polytetrafluoroethylene

1996 ◽  
Vol 4 (1) ◽  
pp. 107-110
Author(s):  
Nathan C. Chaffin ◽  
Peter R. Griffiths
Keyword(s):  
Reference Material ◽  
Reference Materials ◽  
Near Infrared ◽  
Diffuse Reflection ◽  
Infrared Reflection ◽  
Diffuse Reflection Spectrometry

This work reports that inherent absorption by polytetrafluoroethlyene precludes its use as a near infrared or extended near infrared reflection reference material. The effect of this inherent absorption on certain analyte bands is shown. The effectiveness of a previously published method for removing moisture and hydrocarbons from the surface of polytetrafluoroethylene is shown. It is suggested that diffuse gold should be used as the reflection reference material for all measurements made below 5000 cm−1.

Accurate Wavelength Measurements of a Putative Standard for Near-Infrared Diffuse Reflection Spectrometry

2003 ◽  
Vol 57 (2) ◽  
pp. 176-185 ◽  
Author(s):  
Tomas Isaksson ◽  
Husheng Yang ◽  
Gabor J. Kemeny ◽  
Richard S. Jackson ◽  
Qian Wang ◽  
...  
Keyword(s):  
Near Infrared ◽  
Diffuse Reflection ◽  
Center Of Mass ◽  
Baseline Correction ◽  
Peak Picking ◽  
Beam Path ◽  
Polynomial Fit ◽  
Vibration Rotation ◽  
Rotation Spectrum ◽  
Diffuse Reflection Spectrometry

The diffuse reflection (DR) spectrum of a sample consisting of a mixture of rare earth oxides and talc was measured at 2 cm−1 resolution, using five different accessories installed on five different Fourier transform near-infrared (FT-NIR) spectrometers from four manufacturers. Peak positions for 37 peaks were determined using two peak-picking algorithms: center-of-mass and polynomial fitting. The wavenumber of the band center reported by either of these techniques was sensitive to the slope of the baseline, and so the baseline of the spectra was corrected using either a polynomial fit or conversion to the second derivative. Significantly different results were obtained with one combination of spectrometer and accessory than the others. Apparently, the beam path through the interferometer and DR accessory was different for this accessory than for any of the other measurements, causing a severe degradation of the resolution. Spectra measured on this instrument were removed as outliers. For measurements made on FT-NIR spectrometers, it is shown that it is important to check the resolution at which the spectrum has been measured using lines in the vibration-rotation spectrum of atmospheric water vapor and to specify the peak-picking and baseline-correction algorithms that are used to process the measured spectra. The variance between the results given by the four different methods of peak-picking and baseline correction was substantially larger than the variance between the remaining five measurements. Certain bands were found to be more suitable than others for use as wavelength standards. A band at 5943.13 cm−1 (1682.62 nm) was found to be the most stable band between the four methods and the six measurements. A band at 5177.04 cm−1 (1931.61 nm) has the highest precision between different measurements when polynomial baseline correction and polynomial peak-picking algorithms are used.

Role of Scattering Coefficients in Extended Near-Infrared Diffuse Reflection Spectrometry

1998 ◽  
Vol 52 (2) ◽  
pp. 218-221 ◽  
Author(s):  
Nathan C. Chaffin ◽  
Peter R. Griffiths
Keyword(s):  
Near Infrared ◽  
Diffuse Reflection ◽  
Index Of Refraction ◽  
Scattering Coefficient ◽  
Fresnel Reflection ◽  
Scattering Coefficients ◽  
The Matrix ◽  
Bulk Scattering ◽  
Diffuse Reflection Spectrometry

The role of the bulk scattering coefficient in extended near-infrared diffuse reflection (DR) spectrometry of materials with similar or identical absorption coefficients is demonstrated. Spectral differences that arise from intraclass variation in scattering coefficient strongly affect the ability to interpret certain spectral regions. Profound intraclass differences in both band intensities and band shapes in the DR spectra of both polyethylene and polystyrene samples are shown. The effects of saturation and Fresnel reflection are discussed. The enhancement of absorption by the matrix and other analytes in DR spectrometry through the addition of a liquid with an index of refraction which matches that of the matrix is also demonstrated.

ICP-MS AND ICP-AES ANALYSIS OF PLANT REFERENCE MATERIALS

2019 ◽  
Vol 85 (6) ◽  
pp. 11-24
Author(s):  
I. V. Nikolaeva ◽  
A. A. Kravchenko ◽  
S. V. Palessky ◽  
S. V. Nechepurenko ◽  
D. V. Semenova
Keyword(s):  
Reference Material ◽  
Mass Spectrometer ◽  
Reference Materials ◽  
Atomic Emission ◽  
Icp Ms ◽  
Lithium Metaborate ◽  
Relative Standard ◽  
Microwave System ◽  
Total Analysis ◽  
Siberian Pine

Two methods — ICP-MS and ICP-AES are used for certification of the new reference material — needles of Siberian pine (NSP-1). Techniques of the analysis include decomposition of plant samples in two different ways: acid digestion in a microwave system MARS-5 and lithium metaborate fusion followed by ICP-MS and ICP-AES analysis of the solutions. Simultaneous determinations of all the elements were carried out in low, medium and high resolution using SF-mass-spectrometer ELEMENT and atomic-emission spectrometer IRIS Advantage with external calibrations and internal standards (In — ICP-MS, Sc —ICP-AES). Middle and high resolutions of ICP mass spectrometer were used for interference corrections. Data obtained by ICP-MS and ICP-AES with different decomposition techniques are in good agreement. The ICP-MS and ICP-AES techniques have been validated by the analysis of three plant reference materials: LB-1 (leaf of a birch), Tr-1 (grass mixture) and EK-1 (Canadian pondweed). These techniques were used for the determination of 38 elements in the new reference material NSP-1. Relative standard deviations for most of the determined elements were below 10%. Combination of ICP-MS and ICP-AES techniques for certification of the new reference material makes it possible to expand the set of elements to be determined and to reduce the total analysis time.

scholarly journals Development and certification of a reference material for zearalenone in maize germ oil

2021 ◽  
Author(s):  
Juliane Riedel ◽  
Sebastian Recknagel ◽  
Diana Sassenroth ◽  
Tatjana Mauch ◽  
Sabine Buttler ◽  
...  
Keyword(s):  
Reference Material ◽  
Reference Materials ◽  
Mass Fraction ◽  
High Performance ◽  
Certified Reference Materials ◽  
Maximum Level ◽  
Whole Process ◽  
Commission Regulation ◽  
Maize Oil ◽  
Maize Germ

AbstractZearalenone (ZEN), an estrogenic mycotoxin produced by several species of Fusarium fungi, is a common contaminant of cereal-based food worldwide. Due to frequent occurrences associated with high levels of ZEN, maize oil is a particular source of exposure. Although a European maximum level for ZEN in maize oil exists according to Commission Regulation (EC) No. 1126/2007 along with a newly developed international standard method for analysis, certified reference materials (CRM) are still not available. To overcome this lack, the first CRM for the determination of ZEN in contaminated maize germ oil (ERM®-BC715) was developed in the frame of a European Reference Materials (ERM®) project according to the requirements of ISO Guide 35. The whole process of CRM development including preparation, homogeneity and stability studies, and value assignment is presented. The assignment of the certified mass fraction was based upon an in-house study using high-performance liquid chromatography isotope dilution tandem mass spectrometry. Simultaneously, to support the in-house certification study, an interlaboratory comparison study was conducted with 13 expert laboratories using different analytical methods. The certified mass fraction and expanded uncertainty (k = 2) of ERM®-BC715 (362 ± 22) μg kg−1 ZEN are traceable to the SI. This reference material is intended for analytical quality control and contributes to the improvement of consumer protection and food safety. Graphical abstract

Tungsten Suboxide Nanoneedles as an Effective Thermal Shield through Near-Infrared Reflection and Absorption

2021 ◽  
Author(s):  
Jiaxin Yan ◽  
Ashutosh Rath ◽  
Hongyu Wang ◽  
Zhen Quan Cavin Ng ◽  
Stephen J. Pennycook ◽  
...  
Keyword(s):  
Near Infrared ◽  
Thermal Shield ◽  
Infrared Reflection

TC1725 - A Proposed Chalcopyrite Reference Material for LA-MC-ICP-MS Sulfur Isotope Determination

2021 ◽  
Author(s):  
Zhian Bao ◽  
Kaiyun Chen ◽  
Chunlei Zong ◽  
Honglin Yuan
Keyword(s):  
Reference Material ◽  
Reference Materials ◽  
Sulfur Isotope ◽  
Accuracy And Precision ◽  
Icp Ms ◽  
Geochemical Tracer ◽  
Isotope Determination

Sulfur isotope is an important geochemical tracer in diverse fields of geosciences. Controlling the accuracy and precision of microanalysis of sulfur isotope requires well-characterized reference materials with matrices similar to...

Characterization of solid inorganic and coordination compounds by their near infrared reflection spectra

1966 ◽  
Vol 19 (10) ◽  
pp. 1785 ◽  
Author(s):  
AF Reid
Keyword(s):  
Coordination Compounds ◽  
Near Infrared ◽  
Organometallic Compounds ◽  
Reflection Spectra ◽  
Convenient Means ◽  
Infrared Reflection ◽  
Number Of Classes

The near infrared combination spectra of a number of classes of solid inorganic and coordination compounds have been recorded and assigned. The spectra are shown to be typical of particular ligands regardless of the compounds in which they are contained, and to serve as an experimentally convenient means of characterization of solid coordination or organometallic compounds.

New reference materials for trace-levels of actinide elements in plutonium

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Richard M. Essex ◽  
Lav Tandon ◽  
Amy Gaffney ◽  
Cole R. Hexel ◽  
Debbie A. Bostick ◽  
...  
Keyword(s):  
Reference Material ◽  
Reference Materials ◽  
Quartz Glass ◽  
Uranium Isotope ◽  
Glass Bottle ◽  
Plutonium Isotopes ◽  
Mass Fractions ◽  
Trace Constituents ◽  
Actinide Elements

Abstract Two plutonium oxides were prepared as unique reference materials for measurement of actinide elements present as trace constituents. Each reference material unit is approximately 200 mg of PuO2 powder in a quartz glass bottle. Characterized attributes of the oxides included mass fractions of plutonium, americium, neptunium, and uranium. Isotope-amount ratios were also determined for plutonium and uranium, but neptunium and americium were observed to be monoisotopic 237Np and 241Am. Measurements for characterization and verification of the attributes show that plutonium and trace actinides are homogeneous with the exception of limited heterogeneity for uranium, primarily observed for the 238U isotope. Model purification ages calculated from measured americium and uranium attribute values are consistent with material histories and indicate that these impurities are predominantly due to the decay of plutonium isotopes.

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