scholarly journals Spectroscopy as a useful tool for the identification of changes with time in post-mortem vitreous humor for forensic toxicology purposes

2021 ◽  
Author(s):  
Anna Wójtowicz ◽  
Agata Mitura ◽  
Renata Wietecha-Posłuszny ◽  
Rafał Kurczab ◽  
Marcin Zawadzki
Keyword(s):  
Ir Spectra ◽  
Forensic Toxicology ◽  
Principal Component ◽  
Hierarchical Cluster ◽  
Vitreous Humor ◽  
Attenuated Total Reflection ◽  
Glass Slides ◽  
Added Benefit ◽  
Ft Ir ◽  
Non Destructive

AbstractVitreous humor (VH) is an alternative biological matrix with a great advantage of longer availability for analysis due to the lack of many enzymes. The use of VH in forensic toxicology may have an added benefit, however, this application requires rapid, simple, non-destructive, and relatively portable analytical analysis methods. These requirements may be met by Fourier transform infrared spectroscopy technique (FT-IR) equipped with attenuated total reflection accessory (ATR). FT-IR spectra of vitreous humor samples, deposited on glass slides, were collected and subsequent chemometric data analysis by means of Hierarchical Cluster Analysis and Principal Component Analysis was conducted. Differences between animal and human VH samples and human VH samples stored for diverse periods of time were detected. A kinetic study of changes in the VH composition up to 2 weeks showed the distinction of FT-IR spectra collected on the 1st and 14th day of storage. In addition, data obtained for the most recent human vitreous humor samples—collected 3 and 2 years before the study, presented successful discrimination of all time points studied. The method introduced was unable to detect mephedrone addition to VH in the concentration of 10 µg/cm3. Graphic abstract

scholarly journals A Methodology Based on FT-IR Data Combined with Random Forest Model to Generate Spectralprints for the Characterization of High-Quality Vinegars

Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1411
Author(s):  
José Luis P. Calle ◽  
Marta Ferreiro-González ◽  
Ana Ruiz-Rodríguez ◽  
Gerardo F. Barbero ◽  
José Á. Álvarez ◽  
...  
Keyword(s):  
Random Forest ◽  
Raw Materials ◽  
Principal Component ◽  
Hierarchical Cluster ◽  
Raw Material ◽  
Support Vector ◽  
Protected Designation Of Origin ◽  
Ft Ir

Sherry wine vinegar is a Spanish gourmet product under Protected Designation of Origin (PDO). Before a vinegar can be labeled as Sherry vinegar, the product must meet certain requirements as established by its PDO, which, in this case, means that it has been produced following the traditional solera and criadera ageing system. The quality of the vinegar is determined by many factors such as the raw material, the acetification process or the aging system. For this reason, mainly producers, but also consumers, would benefit from the employment of effective analytical tools that allow precisely determining the origin and quality of vinegar. In the present study, a total of 48 Sherry vinegar samples manufactured from three different starting wines (Palomino Fino, Moscatel, and Pedro Ximénez wine) were analyzed by Fourier-transform infrared (FT-IR) spectroscopy. The spectroscopic data were combined with unsupervised exploratory techniques such as hierarchical cluster analysis (HCA) and principal component analysis (PCA), as well as other nonparametric supervised techniques, namely, support vector machine (SVM) and random forest (RF), for the characterization of the samples. The HCA and PCA results present a clear grouping trend of the vinegar samples according to their raw materials. SVM in combination with leave-one-out cross-validation (LOOCV) successfully classified 100% of the samples, according to the type of wine used for their production. The RF method allowed selecting the most important variables to develop the characteristic fingerprint (“spectralprint”) of the vinegar samples according to their starting wine. Furthermore, the RF model reached 100% accuracy for both LOOCV and out-of-bag (OOB) sets.

scholarly journals Evaluation of Volatile Metabolites Emitted In-Vivo from Cold-Hardy Grapes during Ripening Using SPME and GC-MS: A Proof-of-Concept

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 536 ◽  
Author(s):  
Somchai Rice ◽  
Devin Maurer ◽  
Anne Fennell ◽  
Murlidhar Dharmadhikari ◽  
Jacek Koziel
Keyword(s):  
Solid Phase ◽  
Principal Component ◽  
Hierarchical Cluster ◽  
Temporal Variations ◽  
Grape Berry ◽  
Wine Industry ◽  
Gas Chromatography Mass Spectrometry ◽  
Cold Hardy ◽  
Non Destructive

In this research, we propose a novel concept for a non-destructive evaluation of volatiles emitted from ripening grapes using solid-phase microextraction (SPME). This concept is novel to both the traditional vinifera grapes and the cold-hardy cultivars. Our sample models are cold-hardy varieties in the upper Midwest for which many of the basic multiyear grape flavor and wine style data is needed. Non-destructive sampling included a use of polyvinyl fluoride (PVF) chambers temporarily enclosing and concentrating volatiles emitted by a whole cluster of grapes on a vine and a modified 2 mL glass vial for a vacuum-assisted sampling of volatiles from a single grape berry. We used SPME for either sampling in the field or headspace of crushed grapes in the lab and followed with analyses on gas chromatography-mass spectrometry (GC-MS). We have shown that it is feasible to detect volatile organic compounds (VOCs) emitted in-vivo from single grape berries (39 compounds) and whole clusters (44 compounds). Over 110 VOCs were released to headspace from crushed berries. Spatial (vineyard location) and temporal variations in VOC profiles were observed for all four cultivars. However, these changes were not consistent by growing season, by location, within cultivars, or by ripening stage when analyzed by multivariate analyses such as principal component analysis (PCA) and hierarchical cluster analyses (HCA). Research into aroma compounds present in cold-hardy cultivars is essential to the continued growth of the wine industry in cold climates and diversification of agriculture in the upper Midwestern area of the U.S.

Chemometric Approach to a Rapid Attenuated Total Reflection Fourier Transform Infrared Analysis of Complex Heroin-Based Mixtures

2020 ◽  
pp. 000370282096971
Author(s):  
Nataša Radosavljević Stevanović ◽  
Milena Jovanović ◽  
Federico Marini ◽  
Slavica Ražić
Keyword(s):  
Principal Component Analysis ◽  
Fourier Transform ◽  
Principal Component ◽  
Fourier Transform Infrared ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Illegal Market ◽  
Ft Ir

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.

Classification of Vegetable Oils by FT-IR

1997 ◽  
Vol 51 (8) ◽  
pp. 1118-1124 ◽  
Author(s):  
Donald B. Dahlberg ◽  
Shawn M. Lee ◽  
Seth J. Wenger ◽  
Julie A. Vargo
Keyword(s):  
Ir Spectra ◽  
Principal Component ◽  
Fast Detection ◽  
Signal Correction ◽  
Ft Ir ◽  
Ir Detection ◽  
The Fourier Transform ◽  
Cooking Oils ◽  
Cis And Trans

The Fourier transform infrared (FT-IR) spectra of 27 brands of 10 types of cooking oils and margarines were measured without temperature control. Attempts to predict the vegetable source and physical properties of these oils failed until wavelength selection and multiplicative signal correction (MSC) were applied to the FT-IR spectra. After pretreatment of the data, principal component analysis (PCA) was totally successful at oil identification, and partial least-squares (PLS) models were able to predict both the refractive indices [standard error of estimation (SEE) 0.0002] and the viscosities (SEE 0.52 cP) of the oils. These models were based predominately on the FT-IR detection of the cis and trans double-bond content of the oils, as well as small amounts of defining impurities in sesame oils. Efforts to use selected wavelengths to discriminate oil sources were only partially successful. These results show the potential utility of FT-IR in the fast detection of substitution or adulteration of products like cooking oils.

Temperature Dependence of the Mid-Infrared OH Spectral Band in Liquid Water

1997 ◽  
Vol 51 (9) ◽  
pp. 1269-1275 ◽  
Author(s):  
Tetsuo Iwata ◽  
Jun Koshoubu ◽  
Chihiro Jin ◽  
Yusei Okubo
Keyword(s):  
Temperature Dependence ◽  
Liquid Water ◽  
Spectral Band ◽  
Principal Component ◽  
Attenuated Total Reflection ◽  
Vibration Band ◽  
Mid Infrared ◽  
Spectral Components ◽  
Stretching Vibration ◽  
Ft Ir

We have studied the temperature dependence (14–57 °C) of the OH-stretching vibration band in liquid water by the use of a microscope Fourier transform infrared (FT-IR) instrument with an attenuated total reflection (ATR) cell. In order to eliminate spectral distortions, we performed Kramers–Kronig transform of the ATR spectra and derived absorption- and refractive-index spectra. The numerical values are shown in detail. Application of principal component analysis (PCA) and partial least-squares 1 (PLS 1) modeling methods to the absorption-index spectra shows that the OH band consists of two abstract spectral components. The intensity of the first component changes linearly with temperature, whereas the second component changes nonlinearly, with a turning temperature around 30 °C. Each abstract spectrum has a pair of peaks, the intensities of which vary in an inverse manner with respect to each other for the temperature change.

Validated Approaches for Quantification of Bone Mineral Crystallinity Using Transmission Fourier Transform Infrared (FT-IR), Attenuated Total Reflection (ATR) FT-IR, and Raman Spectroscopy

2018 ◽  
Vol 72 (11) ◽  
pp. 1581-1593 ◽  
Author(s):  
William Querido ◽  
Ramyasri Ailavajhala ◽  
Mugdha Padalkar ◽  
Nancy Pleshko
Keyword(s):  
Raman Spectroscopy ◽  
Fourier Transform ◽  
Ir Spectra ◽  
Vibrational Spectroscopy ◽  
Bone Mineral ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Ft Ir ◽  
Mineral Crystallinity ◽  
Ir And Raman

Bone mineral crystallinity is an important factor determining bone quality and strength. The gold standard method to quantify crystallinity is X-ray diffraction (XRD), but vibrational spectroscopic methods present powerful alternatives to evaluate a greater variety of sample types. We describe original approaches by which transmission Fourier transform infrared (FT-IR), attenuated total reflection (ATR) FT-IR, and Raman spectroscopy can be confidently used to quantify bone mineral crystallinity. We analyzed a range of biological and synthetic apatite nanocrystals (10–25 nm) and found strong correlations between different spectral factors and the XRD determination of crystallinity. We highlight striking differences between FT-IR spectra obtained by transmission and ATR. In particular, we show for the first time the absence of the 1030 cm−1 crystalline apatite peak in ATR FT-IR spectra, which excludes its use for analyzing crystallinity using the traditional 1030/1020 cm−1 ratio. The ν4PO4 splitting ratio was also not adequate to evaluate crystallinity using ATR FT-IR. However, we established original approaches by which ATR FT-IR can be used to determine apatite crystallinity, such as the 1095/1115 and 960/1115 cm−1 peak ratios in the second derivative spectra. Moreover, we found a simple unified approach that can be applied for all three vibrational spectroscopy modalities: evaluation of the ν1PO4 peak position. Our results allow the recommendation of the most reliable analytical methods to estimate bone mineral crystallinity by vibrational spectroscopy, which can be readily implemented in many biomineralization, archeological and orthopedic studies. In particular, we present a step forward in advancing the use of the increasingly utilized ATR FT-IR modality for mineral research.

scholarly journals Application of Fourier Transform Infrared Spectroscopy and Multivariate Analysis Methods for the Non-Destructive Evaluation of Phenolics Compounds in Moringa Powder

Agriculture ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 10
Author(s):  
Rahul Joshi ◽  
Ramaraj Sathasivam ◽  
Sang Un Park ◽  
Hongseok Lee ◽  
Moon S. Kim ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Phenolic Compounds ◽  
Ir Spectroscopy ◽  
High Performance ◽  
Principal Component ◽  
Fourier Transform Infrared ◽  
Least Squares Regression ◽  
Ft Ir ◽  
Non Destructive ◽  
Ft Ir Spectroscopy

This study performed non-destructive measurements of phenolic compounds in moringa powder using Fourier Transform Infrared (FT-IR) spectroscopy within a spectral range of 3500–700 cm−1. Three major phenolic compounds, namely, kaempferol, benzoic acid, and rutin, were measured in five different varieties of moringa powder, which was approved with respect to the high-performance liquid chromatography (HPLC) method. The prediction performance of three different regression methods, i.e., partial least squares regression (PLSR), principal component regression (PCR), and net analyte signal (NAS)-based methodology, called hybrid linear analysis (HLA/GO), were compared to achieve the best prediction model. The obtained results for the PLS regression method resulted in better performance for the prediction analysis of phenolic compounds in moringa powder. The PLSR model attained a correlation coefficient () value of 0.997 and root mean square error of prediction (RMSEP) of 0.035 mg/g, respectively, which is comparatively higher than the other two regression models. Based on the results, it can be concluded that FT-IR spectroscopy in conjugation with a suitable regression analysis method could be an effective analytical tool for the non-destructive prediction of phenolic compounds in moringa powder.

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