Spatial Averaging for Solid Samples by Hadamard Transform Raman Spectroscopy

1992 ◽  
Vol 46 (5) ◽  
pp. 778-781 ◽  
Author(s):  
Jianxiong Zhu ◽  
Charles K. Mann ◽  
Thomas J. Vickers
Keyword(s):  
Raman Spectroscopy ◽  
Fiber Optic ◽  
Slit Width ◽  
Hadamard Transform ◽  
Spatial Averaging ◽  
Solid Samples ◽  
Multichannel System ◽  
Sample Heterogeneity

A method is described to avoid the effects of sample heterogeneity in Raman measurements on solid samples. A Hadamard multiplex multichannel system with a bifurcated fiber-optic bundle for excitation and collection is used. The Hadamard mask employs a 7-element code with a unit slit width of 400 μm. Results are reported for samples prepared by mixing cytosine and 5-methylcytosine powders.

Effect of Sample Heterogeneity on near Infrared Meat Analysis: The Use of the RMS Statistic

1998 ◽  
Vol 6 (A) ◽  
pp. A313-A320 ◽  
Author(s):  
M.L. Martínez ◽  
Ana Garrido-Varo ◽  
E. De Pedro ◽  
L. Sánchez
Keyword(s):  
Near Infrared ◽  
Fiber Optic ◽  
Iberian Pig ◽  
Set Up ◽  
Sample Heterogeneity ◽  
Meat Analysis

Ground and emulsified samples from Iberian pig hams were analysed by reflectance and interactance reflectance mode. Spectral errors due to intra-sample variations were calculated for both analysis modes. The spectral errors were calculated by means of the STD RMS statistic included on the ISI software. The results obtained show that a mean STD RMS value as low as 4200, could be obtained for paired subsamples of the same sample and that an STD limit of 4374 could be fixed at the instrument set-up program in order to ensure that a representative spectrum has been obtained from two subsamples readings of the same sample. That procedure avoids the need to take numerous subsamples, as is traditional in NIR/NIT meat analysis. The results also show that the spectral repeatability using fiber optic is worse than for spinning cups and it has been concluded that effort should be made to avoid moisture variations during scanning in order to improve spectral repeatability.

scholarly journals Real-time In vivo Diagnosis of Nasopharyngeal Carcinoma Using Rapid Fiber-Optic Raman Spectroscopy

Theranostics ◽  
2017 ◽  
Vol 7 (14) ◽  
pp. 3517-3526 ◽  
Author(s):  
Kan Lin ◽  
Wei Zheng ◽  
Chwee Ming Lim ◽  
Zhiwei Huang
Keyword(s):  
Raman Spectroscopy ◽  
Nasopharyngeal Carcinoma ◽  
Real Time ◽  
Fiber Optic ◽  
In Vivo Diagnosis

Applications of the Rotating Solid Sample Technique in Raman Spectroscopy

1972 ◽  
Vol 26 (6) ◽  
pp. 589-593 ◽  
Author(s):  
Howard J. Sloane ◽  
R. B. Cook
Keyword(s):  
Raman Spectroscopy ◽  
General Solution ◽  
Laser Beam ◽  
Resonance Raman ◽  
Solid Sample ◽  
Energy Losses ◽  
Solid Samples ◽  
Pale Yellow ◽  
Sample Technique ◽  
Argon Ion

Use of a rotating solid sample device in the Raman examination of deeply colored highly absorbing samples was investigated. A wide variety of inorganic, organic, and metallorganic compounds ranging in color from pale yellow to orange-red and black were studied using 4880 Å or 5145 Å argon ion excitation. Good quality spectra were obtained from solid samples which previously were either destroyed by conventional static excitation or required defocusing or attenuation of the laser beam with attendant energy losses. The technique appears to offer a general solution to the problem of highly absorbing samples which decompose because of localized overheating by absorption of the source radiation. In some cases, resonance Raman effects may be studied.

scholarly journals Fiber Optic Coupled Raman Based Detection of Hazardous Liquids Concealed in Commercial Products

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Michael L. Ramírez-Cedeño ◽  
Natalie Gaensbauer ◽  
Hilsamar Félix-Rivera ◽  
William Ortiz-Rivera ◽  
Leonardo Pacheco-Londoño ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Raman Spectroscopy ◽  
Fiber Optic ◽  
Hazardous Materials ◽  
Chemical Warfare Agent ◽  
Chemical Warfare ◽  
Consumer Products ◽  
Algorithm Analysis ◽  
Triethyl Phosphate ◽  
Industrial Compounds

Raman spectroscopy has been widely proposed as a technique to nondestructively and noninvasively interrogate the contents of glass and plastic bottles. In this work, Raman spectroscopy is used in a concealed threat scenario where hazardous liquids have been intentionally mixed with common consumer products to mask its appearance or spectra. The hazardous liquids under consideration included the chemical warfare agent (CWA) simulant triethyl phosphate (TEP), hydrogen peroxide, and acetone as representative of toxic industrial compounds (TICs). Fiber optic coupled Raman spectroscopy (FOCRS) and partial least squares (PLS) algorithm analysis were used to quantify hydrogen peroxide in whiskey, acetone in perfume, and TEP in colored beverages. Spectral data was used to evaluate if the hazardous liquids can be successfully concealed in consumer products. Results demonstrated that FOC-RS systems were able to discriminate between nonhazardous consumer products and mixtures with hazardous materials at concentrations lower than 5%.

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