Carlos H.V. Fidelis

Classification of Amazonian rosewood essential oil by Raman spectroscopy and PLS-DA with reliability estimation

The Amazon tree Aniba rosaeodora Ducke (rosewood) provides an essential oil valuable for the perfume industry, but after decades of predatory extraction it is at risk of extinction. The extraction of the essential oil from wood implies the cutting of the tree, and then the study of oil extracted from the leaves is important as a sustainable alternative. The goal of this study was to test the applicability of Raman spectroscopy and Partial Least Square Discriminant Analysis (PLS-DA) as means to classify the essential oil extracted from different parties (wood, leaves and branches) of the Brazilian tree A. rosaeodora. For the development of classification models, the Raman spectra were split into two sets: training and test. The value of the limit that separates the classes was calculated based on the distribution of samples of training. This value was calculated in a manner that the classes are divided with a lower probability of incorrect classification for future estimates. The best model presented sensitivity and specificity of 100%, predictive accuracy and efficiency of 100%. These results give an overall vision of the behavior of the model, but do not give information about individual samples; in this case, the confidence interval for each sample of classification was also calculated using the resampling bootstrap technique. The methodology developed have the potential to be an alternative for standard procedures used for oil analysis and it can be employed as screening method, since it is fast, non-destructive and robust.

Quantification of Kerosene in Gasoline by Comprehensive Two-Dimensional Gas Chromatography and N-Way Multivariate Analysis

Abstract In brazil, gasoline is usually adulterated by diesel oil, ethanol (in addition to the amount legally specified), petrochemical raffinates, and kerosene. This is an illegal action performed mainly in an attempt to raise profits. Therefore, methods for reliable identification of adulterated gasoline are very attractive. The aim of this work was to propose a method to quantify kerosene in gasoline through N-way multivariate analysis and a homemade Comprehensive Two-Dimensional Gas Chromatography with Flame Ionization Detection (GC × GC-FID). Models generated by Parallel Factor Analysis (PARAFAC), PARAFAC2, and Multi-way Partial Least Squares (N-PLS) allowed the quantification of kerosene in gasoline with Root Mean Square Error of Cross-Validation (RMSECV) values of 2.98%, 2.65%, and 2.08%, respectively.

Chemical characterization of rosewood (Aniba rosaeodora Ducke) leaf essential oil by comprehensive two-dimensional gas chromatography coupled with quadrupole mass spectrometry

The Amazonian tree Aniba rosaeodora Ducke, whose wood provides commercial essential oil for perfumery houses, is at risk of extinction and listed by CITES. An alternative source of this oil would be to trim leaves of young plants and steam distill them to obtain the essential oil. Four-year-old plant material could provide an oil that can both be an economical source and eventually a replacement for wood oil in perfumery. A characterization of the essential oil from these leaves has been obtained by comprehensive two-dimensional gas chromatography. The two-dimensional analytical technique was able to separate and identify about three times more compounds than is the case with conventional gas chromatography, leading to a more complete essential oil chemical characterization.

Differentiation of two morphologically similar Amazonian Aniba species by mass spectrometry leaf fingerprinting

The wood of the Amazonian tree Aniba rosaeodora Ducke has been intensively exploited since the 1920s and remains a much valued material in the perfume industry, leading to its classification as a plant at risk of extinction. Another Amazonian tree, Aniba parviflora, is morphologically highly similar to the much more valuable A. rosaeodora and is illegally commercialized in the seedling stage as counterfeit samples of the much more valuable A. rosaeodora. A technique that would be able to perform rapid, versatile and reliable differentiation of the two species would therefore be valuable to detect such illegal practice. Herein we describe unequivocal differentiation between the two morphologically similar Amazonian Aniba species by leaf mass spectrometry fingerprinting using a small fragment of the leaf. Two ionization techniques were tested (ESI and VL-EASI), and mass spectra obtained from many leaves and at different points on the leaf surface belonging to the same species were very similar and reproducible, whereas spectra between the two species were markedly different. Marker ions detected in each spectrum were structurally characterized based on the accurate mass measurements, MS/MS fragmentation patterns and comparison of the results with reported data. Principal component analysis (PCA) was used to validate the differentiation of the spectra. MS leaf fingerprinting using both ESI and VL-EASI offers therefore a rapid, versatile and reliable method to differentiate morphologically similar plant species, as demonstrated herein for the two Amazonian Aniba species at the seedling stage.

Linalool enantiomeric distribution in rosewood-reminiscent populations in Central Amazon

ABSTRACT The enantiomeric distribution of linalool can strongly impact the fragrance of essential oils, thereby affecting the usage criteria of linalool for the perfumery industry. The enantiomers 3R-(−)-linalool and 3S-(+)-linalool present distinctive aromas; the former is woody, floral and lavender-like, while the latter is sweet, herb-like and citric. The aim of this research was to investigate variations in the enantiomeric distribution of linalool in oils extracted from the leaves and branches of 54 samples from rosewood (Aniba rosaeodora Ducke) trees in natural populations in the Brazilian Amazon. The essential oil was obtained by hydrodistillation, and the analysis of enantiomer composition was performed using chiral gas chromatography. The ratio 3R-(−)-linalool:3S-(+)-linalool varied between 5:95 and 44:56 in the samples. The enantiomeric distribution was not significantly different between oils from leaves across different collection sites but was significantly different between leaves and branches, indicating that these plant organs have distinct olfactory properties.

Analysis of electrocautery generated smoke by chromatographic-mass spectrometry

OBJECTIVE to analyze the chemical components of the smoke from electrocautery from coagulating muscle and liver tissues of pigs. METHODS we collected smoke produced by electrocautery applied to porcine tissue in previously evacuated bottles, with qualitative and quantitative analysis of the compounds present through the hyphenated technique gas chromatography / mass spectrometry. RESULTS there was a majority of decanal aldehyde in the fumes from the subcutaneous, muscle and liver tissues. Fumes of subcutaneous and muscular tissues also showed the presence of hexanal and phenol. In the fumes of subcutaneous and liver tissues we also found toluene and limonene and, finally, nonanal smoke was present in the muscle and liver tissues. CONCLUSION there is increasing evidence showing that smoke from electrocautery used in subcutaneous, muscle and liver tissue is harmful to human health. Thus, there is need to reduce exposure to it or wear masks with filters capable of retaining these particles. OBJETIVO analisar quimicamente os componentes da fumaça do eletrocautério, provenientes da coagulação de tecidos, muscular e hepático de suino. MÉTODOS coleta de fumaça produzida por eletrocauterização de tecido porcino em frascos previamente evacuados com análise qualitativa e quantitativa dos compostos presentes, através de técnica hifenada, cromatografia a gás/espectrometria de massas. RESULTADOS houve presença majoritária do aldeído decanal nas fumaças provenientes dos tecidos subcutâneo, muscular e hepático. Fumaças dos tecidos subcutâneo e muscular mostraram também a presença de hexanal e fenol. Nas fumaças dos tecidos subcutâneo e hepático foram encontrados ainda tolueno e limoneno e, por fim, nonanal estava presente nas fumaças dos tecidos muscular e hepático. CONCLUSÃO há número crescente de evidências mostrando que fumaça proveniente de eletrocauterização de tecidos subcutâneo, muscular e hepático é nociva à saúde de seres humanos. Portanto, há necessidade de reduzir a exposição a ela ou usar máscara com filtro capaz de reter essas partículas.