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.

Method for the Classification of Biological FT-IR Spectra Prior to Quantitative Analysis

1996 ◽  
Vol 50 (12) ◽  
pp. 1590-1596 ◽  
Author(s):  
Frédéric Cadet
Keyword(s):  
Ir Spectra ◽  
Principal Component Regression ◽  
Principal Component ◽  
Quantitative Measurements ◽  
Raw Sugar ◽  
Qualitative Classification ◽  
Ft Ir ◽  
The Mean ◽  
Euclidian Distances

Several methods have been proposed with the aim of improving the precision of quantitative measurements of biological components (baseline correction, classification, elimination of unwanted components, etc.). In this context, we propose a classification method of biological samples (raw sugar cane juices) before sucrose content prediction is performed. The method consisted of isolating the two most dissimilar individuals from a large calibration family of mid-FT-IR spectra, and, by successive principal component analysis (PCA) and principal component regression (PCR), a family composed of a few individuals was constituted. Each individual from this family represented the first spectrum of the corresponding classes that were ultimately formed. The classification of the remaining samples from the calibration family was carried out by the mobile centers method, that is, by the measurements of the Euclidian distances. This procedure improved the precision of the predictions. The mean and standard deviation (SD) of the differences between predicted and reference values were, respectively, −1.62 × 10−3 and 0.308 before classification and 2.38 × 10−3 and 0.254 after classification. The procedure developed in this paper first allowed a qualitative classification of spectra without knowledge of their chemical composition, and second, improved the precision of the quantitative predictions.

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

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.

Vibrational spectra of solid cis- and trans-2-thioxohexahydroquinazolin-4(1H)-one and theoretical calculations towards the interpretation of its thermal reactivity

RSC Advances ◽  
2015 ◽  
Vol 5 (54) ◽  
pp. 43345-43352 ◽  
Author(s):  
A. G. Iriarte ◽  
W. J. Peláez ◽  
F. Fülöp ◽  
G. A. Argüello
Keyword(s):  
Ir Spectra ◽  
Vibrational Spectra ◽  
Solid Phase ◽  
Theoretical Calculations ◽  
Thermal Reactivity ◽  
Ft Ir ◽  
Cis And Trans ◽  
Ft Raman

FT-Raman and FT-IR spectra ofcisandtrans2-thioxohexahydroquinazolin-4(1H)-one are reported. Both compounds are dimers in the solid phase, withC2symmetry. This work contributes to the knowledge of data which are rather scarce for quinazolinones.

Platinum(II) and magnesium(II) nucleotide complexes. Synthesis, FT-ir spectra, and structural properties

1983 ◽  
Vol 61 (8) ◽  
pp. 1813-1822 ◽  
Author(s):  
H. A. Tajmir-Riahi ◽  
T. Theophanides
Keyword(s):  
Water Molecule ◽  
Ir Spectra ◽  
Metal Ions ◽  
Structural Properties ◽  
Acidic Solution ◽  
Neutral Solution ◽  
Metal Bonding ◽  
Ft Ir ◽  
Cis And Trans ◽  
Chemical Evidence

Guanosine-5′-monophosphate (5′-GMP) reacts with Pt(II) and Mg(II) metal ions to give complexes of the type Pt(5′-GMP)nCl2•xH2O, cis- and trans-[Pt(NH3)2(5′-GMP)2]Cl2•xH2O and Mg(5'-GMP2)•xH2O, where n = 1, 2, 3, 4 and x = 4–10.Spectroscopic and chemical evidence showed marked similarities with those of the structurally known N7-bonded 5′-GMP complexes of Mn(II), Co(II), Ni(II), Cu(II), and Cd(II) metal ions. Therefore, Pt(II) and Mg(II) are also found to be N7-bonded in these series of nucleotide complexes.The direct phosphate coordination was observed in Mg(II) nucleotide complexes obtained from acidic solution, whereas Mg(II) complexes prepared from neutral solution showed no direct phosphate–Mg(II) interaction. Pt(II) complexes exhibited no direct phosphate metal bonding, while the possibility of an indirect Pt(II)–phosphate interaction through a hydrogen-bonded water molecule can be proposed here.

Cluster Analysis of Gallstone FT-IR Spectra: Tests on Simulated Mixture Spectra and Comparison between Spectral and Morphological Classification of Human Gallstones

1998 ◽  
Vol 52 (9) ◽  
pp. 1210-1221 ◽  
Author(s):  
Eric Laloum ◽  
Nguyen Quy Dao ◽  
Michel Daudon
Keyword(s):  
Cluster Analysis ◽  
Ir Spectra ◽  
Black Pigment ◽  
Brown Pigment ◽  
Morphological Classification ◽  
Single Linkage ◽  
Homogeneous Groups ◽  
Ft Ir ◽  
Pure Cholesterol

Sixty-four combination spectra of three major gallstone components [i.e., cholesterol, calcium bilirubinate, and calcium carbonate (aragonite)] were simulated in accordance with a “fractal” ternary diagram. Comparison between the original pattern of composition and factorial maps of pretreated spectra makes it possible to show the effects of different normalization procedures (Euclidean norm, spectrum maximum, and area under spectrum set to 1). Cluster analysis of these spectra, depending on different agglomerative links (single linkage, complete linkage, average linkage, and Ward's criterion), was carried out. All the resultant trees yield the same groups, but Ward's criterion best preserves the pattern of the data. More than 100 gallstones from France and Vietnam were classified by using cluster analysis of their FT-IR spectra with Ward's criterion. Seven homogeneous groups of spectra were extracted, which have been significantly correlated to the four morphological types of gallstones: pure cholesterol, mixed cholesterol, brown pigment, and black pigment stones. This analysis also reveals that the morphological groups are not homogeneous in composition, in particular for black pigment stones.

scholarly journals Application of Spectroscopic UV-Vis and FT-IR Screening Techniques Coupled with Multivariate Statistical Analysis for Red Wine Authentication: Varietal and Vintage Year Discrimination

Molecules ◽  
2019 ◽  
Vol 24 (22) ◽  
pp. 4166 ◽  
Author(s):  
Elisabeta-Irina Geană ◽  
Corina Teodora Ciucure ◽  
Constantin Apetrei ◽  
Victoria Artem
Keyword(s):  
Discriminant Analysis ◽  
Principal Component ◽  
Total Variance ◽  
Red Wines ◽  
Linear Discriminant ◽  
Vis Spectroscopy ◽  
Ft Ir ◽  
Wine Authentication ◽  
Analytical Approaches

One of the most important issues in the wine sector and prevention of adulterations of wines are discrimination of grape varieties, geographical origin of wine, and year of vintage. In this experimental research study, UV-Vis and FT-IR spectroscopic screening analytical approaches together with chemometric pattern recognition techniques were applied and compared in addressing two wine authentication problems: discrimination of (i) varietal and (ii) year of vintage of red wines produced in the same oenological region. UV-Vis and FT-IR spectra of red wines were registered for all the samples and the principal features related to chemical composition of the samples were identified. Furthermore, for the discrimination and classification of red wines a multivariate data analysis was developed. Spectral UV-Vis and FT-IR data were reduced to a small number of principal components (PCs) using principal component analysis (PCA) and then partial least squares discriminant analysis (PLS-DA) and linear discriminant analysis (LDA) were performed in order to develop qualitative classification and regression models. The first three PCs used to build the models explained 89% of the total variance in the case of UV-Vis data and 98% of the total variance for FR-IR data. PLS-DA results show that acceptable linear regression fits were observed for the varietal classification of wines based on FT-IR data. According to the obtained LDA classification rates, it can be affirmed that UV-Vis spectroscopy works better than FT-IR spectroscopy for the discrimination of red wines according to the grape variety, while classification of wines according to year of vintage was better for the LDA based FT-IR data model. A clear discrimination of aged wines (over six years) was observed. The proposed methodologies can be used as accessible tools for the wine identity assurance without the need for costly and laborious chemical analysis, which makes them more accessible to many laboratories.

Forensic Classification of Paper with Infrared Spectroscopy and Principal Components Analysis

2005 ◽  
Vol 13 (4) ◽  
pp. 225-229 ◽  
Author(s):  
Ashwini Kher ◽  
Samantha Stewart ◽  
Mary Mulholland
Keyword(s):  
Near Infrared ◽  
Principal Component ◽  
Infrared Region ◽  
Discriminating Power ◽  
Chemometric Technique ◽  
Ft Ir ◽  
Components Analysis ◽  
Processing Techniques ◽  
The Impact

Fourier transform infrared (FT-IR) spectra of six document papers were classified by the chemometric technique of soft independent modelling of class analogy (SIMCA) using principal component analysis (PCA). The data were split into two regions, mid infrared (MIR, 2500–4000 cm−1) and the near infrared region (NIR, 4000–9000 cm−1). The raw data failed to produce an appreciable separation; hence it was pre-processed using derivatives and the multiple wavenumber ratios technique. The aim of this research was to determine the spectral region with the best discriminating power and evaluate the impact of data pre-processing techniques on the classification of paper. It was found that MIR (both raw and ratios) had higher discriminating ability than the NIR. The first derivatives and two ratios produced the best classifications. These results indicate that IR spectroscopy coupled with chemometric analyses can be effectively employed for the forensic classification of paper.

scholarly journals Bentonite as a Refining Agent in Waste Cooking Oils Recycling: Flash Point, Density and Color Evaluation

2018 ◽  
Vol 13 (5) ◽  
pp. 1934578X1801300 ◽  
Author(s):  
Alberto Mannu ◽  
Gina Vlahopoulou ◽  
Veronica Sireus ◽  
Giacomo Luigi Petretto ◽  
Gabriele Mulas ◽  
...  
Keyword(s):  
Flash Point ◽  
Oil Refining ◽  
Filling Material ◽  
Early Results ◽  
Early Classification ◽  
Waste Cooking Oils ◽  
Point Density ◽  
Ft Ir ◽  
Cooking Oils

Clarification of waste recycled cooking oil (WCO) is very important in order to refine the intermediate regenerated base resulting from the previous steps. Bentonite has been historically employed as a filling material for oil refining filters due to its easy availability and its cheap price. In the present communication our early results from the filtration of degummed WCO through a pad of bentonite are presented. In particular, the variation of density, flash point and color have been monitored prior and after the filtration process and compared with samples of non-filtered WCO. An early classification of the bentonite employed has been conducted on the basis of FT-IR and XRD measurements.

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