Multivariate Analysis of Attenuated Total Reflection Fourier Transform Infrared (ATR FT-IR) Spectroscopic Data to Confirm Phase Partitioning in Methacrylate-Based Dentin Adhesive

Heroin is one of the most frequently seized drugs in Southeastern Europe. Due to the position in the Balkan route, the Republic of Serbia keeps important role in suppression of the trafficking of heroin for domestic and foreign illegal market. This research is aimed to provide a good scientific approach in the field of seized heroin analysis. Two different forms of heroin are present in the illegal market, mostly in mixtures with typical “cutting” agents: caffeine, paracetamol, and sugars. It was observed that the quantity of pure heroin in seized samples slightly increases from year to year. The aim of this study was to produce a reliable and fast procedure for classification of illicit heroin samples and determination of the concentration range of heroin in the samples. For that purpose, the attenuated total reflection Fourier transform infrared spectroscopy (ATR FT-IR) technique was used and combined with such chemometric methods as principal component analysis, cluster analysis, and partial least squares. Principal component analysis (PCA) as an unsupervised model was used for exploratory purposes to identify trends, similarities, and differences between samples by reducing the dimensionality of the data. The cluster classification of examined samples turned out to be extremely useful to evaluate the possibilities of the ATR FT-IR technique to classify the samples appropriately into the patterns, the constituted clusters. Additionally, partial least square was the suitable method for the purpose of determination of the heroin hydrochloride concentration range in examined samples. It is proved that the joined application of spectroscopy and chemometrics can be extremely convenient and useful for forensic and drugs control laboratories.

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Discerning Some Tylenol Brands Using Attenuated Total Reflection Fourier Transform Infrared Data and Multivariate Analysis Techniques

Applied Spectroscopy ◽

10.1366/000370210791414425 ◽

2010 ◽

Vol 64 (6) ◽

pp. 657-668 ◽

Cited By ~ 4

Author(s):

Huggins Z. Msimanga ◽

Robert J. Ollis

Keyword(s):

Multivariate Analysis ◽

Fourier Transform ◽

Fourier Transform Infrared ◽

Total Reflection ◽

Attenuated Total Reflection ◽

Analysis Techniques ◽

Infrared Data

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Novel Attenuated Total Reflection Fourier Transform Infrared Microscopy Using a Gem Quality Diamond as an Internal Reflection Element

Applied Spectroscopy ◽

10.1366/000370205774430972 ◽

2005 ◽

Vol 59 (10) ◽

pp. 1236-1241 ◽

Cited By ~ 1

Author(s):

Sanong Ekgasit ◽

Pimthong Thongnopkun

Keyword(s):

Fourier Transform ◽

Total Internal Reflection ◽

Fourier Transform Infrared ◽

Normal Incidence ◽

Total Reflection ◽

Attenuated Total Reflection ◽

Internal Reflection ◽

The Novel ◽

Infrared Microscope ◽

Ft Ir

A novel technique for attenuated total reflection Fourier transform infrared (ATR FT-IR) spectral acquisition by an infrared microscope with a gem-quality faceted diamond as an internal reflection element (IRE) is introduced. Unlike conventional IREs, the novel diamond IRE has a sharp tip configuration instead of a flat tip configuration. Light at normal incidence was coupled into the diamond while the transflected radiation from the diamond was collected through the table facet by the built-in 15× Cassegrainian objective. The number of reflections in the novel diamond IRE equals two. The evanescent field generated under total internal reflection at the pavilion facet was exploited for ATR spectral acquisition of materials attached to the IRE. The observed ATR spectra were compared to those obtained via a traditional zinc selenide IRE.

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Multivariate Analysis of Attenuated Total Reflection—Fourier Transform Infrared Spectroscopic Data to Confirm the Origin of Honeys

Applied Spectroscopy ◽

10.1366/000370208786049033 ◽

2008 ◽

Vol 62 (10) ◽

pp. 1115-1123 ◽

Cited By ~ 26

Author(s):

Siobhán Hennessy ◽

Gerard Downey ◽

Colm O'Donnell

Keyword(s):

Fourier Transform ◽

Discriminant Analysis ◽

Fourier Transform Infrared ◽

Total Reflection ◽

Attenuated Total Reflection ◽

Correct Classification ◽

Standard Normal Variate ◽

Standard Normal ◽

Ft Ir ◽

Solids Content

Fourier transform infrared (FT-IR) spectroscopy and chemometrics were used to verify the origin of honey samples ( n = 150) from Europe and South America. Authentic honey samples were collected from five sources, namely unfiltered samples from Mexico in 2004, commercially filtered samples from Ireland and Argentina in 2004, commercially filtered samples from the Czech Republic in 2005 and 2006, and commercially filtered samples from Hungary in 2006. Samples were diluted with distilled water to a standard solids content (70° Brix) and their spectra (2500–12 500 nm) recorded at room temperature using an FT-IR spectrometer equipped with a germanium attenuated total reflection (ATR) accessory. First- and second-derivative and standard normal variate (SNV) data pretreatments were applied to the recorded spectra, which were analyzed using partial least squares (PLS) regression analysis, factorial discriminant analysis (FDA), and soft independent modeling of class analogy (SIMCA). In general, when an attenuated wavelength range (6800–11 500 nm) rather than the whole spectrum (2500–12 500 nm) was studied, higher correct classification rates were achieved. An overall correct classification of 93.3% was obtained for honeys by PLS discriminant analysis, while FDA techniques correctly classified 94.7% of honey samples. Correct classifications of up to 100% were achieved using SIMCA, but models describing some classes had very high false positive rates.

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