Multivariate optimization of a HS-SPME/GC-MS technique for the characterization of volatile compounds present in Hedeoma multiflorum Benth / Optimización Multivariada de una técnica HS-SPME/GC para la caracterización de los compuestos volátiles presentes en Hedeoma multiflorum Benth

The aim of the present work was to optimize the main experimental variables of a procedure using HS-SPME/GC-MS as the analytical methodology to establish the profile of the volatile compounds present in aerial parts of Hedeoma multiflorum Benth. The influence of the type of fiber, equilibrium time, extraction time and extraction temperature on the composition of the volatile compounds was determined using response surface methodology (RSM), and the parameters of the models were corroborated by multiple linear regressions. The results showed that the regression models generated adequately explained the data variation and represented the relationships between the parameters and their responses. The optimal analysis conditions from the contour plots were established (DVB/CAR/PDMS fiber, with a 10 min equilibrium time, 10 min extraction time, and 40°C). Under these conditions, 41 volatile components in the whole plant were determined, which represents more than those reported using hydrodistillation.

El objetivo del presente trabajo fue optimizar las principales variables experimentales de un procedimiento HS-SPME/GC para establecer el perfil de compuestos volátiles presentes en la parte aérea de Hedeoma multiflorum Benth. Se determinó la influencia de las variables tipo de fibra, tiempo de equilibrio, tiempo de extracción y temperatura de extracción sobre la composición de los volátiles, utilizando una met odología de superficie de respuesta (RSM) y los parámetros del modelo se corroboraron por regresión lineal múltiple. Los resultados demostraron que los modelos de regresión generados explican adecuadamente la variación de los datos y representaron significativamente las relaciones reales entre los parámetros y sus respuestas. Las condiciones óptimas de análisis fueron establecidas (DVB/CAR/PDMS, con un tiempo de equilibrio de 10 minutos, un tiempo de extracción de 10 minutos y trabajando a 40°C). Utilizando esta metodología, se determinaron 41 componentes volátiles en planta entera, más que los reportados mediante hidrodestilación.

Relationship between the Change Rules of Volatile Organic Compounds in Rat Muscle and Postmortem Interval / 法医学杂志

OBJECTIVES@#To explore the relationship between the change rules of volatile organic compounds （VOCs） in rat muscle and postmortem interval （PMI）.@*METHODS@#A total of 120 healthy rats were divided randomly into 12 groups （10 for each group）. After the rats were sacrificed by cervical dislocation, the bodies were kept at （25±1） ℃. Rat muscle samples were separately obtained at 12 PMI points, including 0, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 d. The VOCs in rat muscles were collected, detected and analyzed by headspace solid-phase microextraction （HS-SPME） coupled to gas chromatography-mass spectrometer （GC-MS）.@*RESULTS@#In total, 15 species of VOCs were identified, including 9 aromatic compounds, 3 sulfur compounds, 2 aliphatic acids and 1 heterocyclic compound. The species of VOCs increased with PMI： no species were detected within 1 day, 3 species were detected on day 2, 9 on day 3, 11 on day 4, 14 from day 5 to 7, and 15 from day 8 to 10. Total peak area of 15 species of VOCs was significantly correlated to PMI （adjusted R²=0.15-0.96）： the regression function was y=-17.05 x²+ 164.36 x-246.36 （adjusted R²=0.96） from day 2 to 5, and y=2.24 x+101.13 （adjusted R²=0.97） from day 6 to 10.@*CONCLUSIONS@#The change rules of VOCs in rat muscle are helpful for PMI estimation.

Comparison of volatile compounds in Retanilla trinervia [Gillies & Hook] Hook & Arn honeys from central Chile / Comparación de compuestos volátiles en mieles de Retanilla trinervia[Gillies & Hook] Hook & Arn de Chile Central

The search for chemical markers for determining honey authenticity as a complementary tool for melissopalynological method is an important issue in the study of honeys from different botanical origins. The objective of this study was to determine the volatile compounds in tevo (Retanilla trinervia [Gillies & Hook] Hook & Arn [Fam. Rhamnaceae]) honey as one of the most relevant honeys from central Chile. For the identification and quantification of volatile compounds, Solid-Phase Microextraction and Gas Chromatography with Mass Spectrometry (SPME-GC-MS) was performed. A total of 28 out of 103 volatile compounds were found common to the five tevo honeys analyzed. Nevertheless, these compounds are common in unifloral honey of different floral sources from other countries. These results represent the first record in the identification of volatile compounds in tevo honey and would indicate that tevo honey does not present specific volatile compounds that allow its clear differentiation from other unifloral honey.

La búsqueda de marcadores químicos para determinar la autenticidad de la miel como una herramienta complementaria al análisis melisopalinológico es un tema importante en el estudio de las mieles de diferentes orígenes botánicos. El objetivo de este estudio fue determinar los compuestos volátiles en miel de tevo (Retanilla trinervia [Gillies & Hook] Hook & Arn [Fam. Rhamnaceae]), una de las mieles más relevantes de Chile Central. La identificación y cuantificación de compuestos volátiles se llevó a cabo mediante Microextracción en Fase Sólida y Cromatografía de Gases con Espectrometría de Masas (SPME-CG-MS). Un total de 28 de los 103 compuestos volátiles identificados en las cinco mieles de tevo analizadas se encontraron en común para ellas. Sin embargo, estos compuestos son comunes en la miel monofloral de diferentes fuentes florales de otros países. Estos resultados representan los primeros avances en la identificación de compuestos volátiles en la miel de tevo e indicarían que la miel de tevo no presenta compuestos volátiles específicos que permitan su clara diferenciación respecto a otras mieles monoflorales.

Floral scents of four Heliotropium (Boraginaceae) species endemic to Chile: a comparative analysis / Aromas florales de cuatro especies de Heliotropium (Boraginaceae) endémicas de Chile: un análisis comparativo

The floral volatile chemicals of four Heliotropium (Boraginaceae) species endemic to Chile are described and their relationship with an Heliotropium phylogeny assessed. Twenty-two compounds were identified; the most prominent family of compounds in H. floridum, H. myosotifolium and H. stenophyllum were benzenoids, and in H. pycnophyllum prominence of benzenoids was shared with two monoterpenes, (E)-Ocymene and 1,8-cineol. The similarity between chemical mixtures of the species significantly decreased with increasing phylogenetic distance between them. Neighbor-joining analysis produced a tree topology with one clade comprised by H. myosotifolium and H. stenophyllum and an unresolved relationship between this clade and H. floridum and H. pycnophyllum; this topology bears a close relationship with molecular phylogeny proposed for the group. These preliminary results presented suggest that the genus Heliotropium complies with the condition of phylogenetically-related floral scent interspecific variation, a key condition in studies of plant-pollinator coevolution mediated by them.

Se describieron los volátiles florales de cuatro especies de Heliotropium (Boraginaceae) y se evaluó su relación con una filogenia del género. Se identificaron 22 compuestos; los bencenoides fueron los más abundantes en H. floridum, H. myosotifolium and H. stenophyllum, acompañados de dos monoterpenos, el (E)-Ocimeno y el 1,8-cineol, en H. pycnophyllum. La similitud entre los componentes de cada especie aumentó con la distancia filogenética entre ellas. El análisis “neighbor-joining” produjo un árbol con un clado que contenía a H. myosotifolium y H. stenophyllum y una relación no resuelta entre ese clado y H. floridum y H. pycnophyllum; esta topología guarda similitud con la hipótesis filogenética molecular propuesta para el grupo. Estos resultados preliminares sugieren que el género Heliotropium cumple con la condición de mostrar variación interespecífica en sus volátiles florales, condición básica para estudios de coevolución planta-polinizador mediada por ellos.

Performance catalytic ozonation over the carbosieve in the removal of toluene from waste air stream

Toluene is a volatile organic compound, one of 189 hazardous air pollutants [HAP[s]] and the most important pollutant found in most industries and indoor environments; owing to its adverse health, toluene must be treated before being released into the environment. In this research study, a continuous-flow system [including an air compressor, silica gel filters and activated charcoal, impinger, an ozone generation and a fixed bed reactor packed with the carbosieve in size 1.8-2.3 mm, specific surface: 972 m[2]/g,] was used. This glass reactor was 0.7 m in height; at a distance of 0.2 m from its bottom, a mesh plane was installed so as to hold the adsorbent. Moreover, 3 l/min oxygen passed through this system, 0.43 g/h ozone was prepared. The flow rate of waste airstream was 300 ml/min. The efficiency of this system for removal of toluene was compared under the same experimental conditions. Under similar conditions, performance of catalytic ozonation was better in toluene removal than that of ozonation and carbosieve alone. On average, increasing the removal efficiency was 45% at all concentrations. When carbosieve and ozone come together, their synergistic effects increased on toluene degradation. Catalytic ozonation is a suitable, high-efficient and available method for removing toluene from various concentrations of waste air stream. This process due to the short contact time, low energy consuming and making use of cheap catalysts can be used as a novel process for removing various concentrations of volatile organic compounds

Volatile organic compounds [VOCs] pollutants in two contrastive industrial areas in Lagos - state, southwestern - Nigeria

VOCs are important class of air pollutants because they are ubiquitous and associated with increased short- and long-term health risks in the industrial areas and environs. The air samples were collected by passive sampler [ORSA 5] from two con-trastive industrial areas such as Ikeja and Isolo industrial areas. The air samplers were exposed to a height of 1.5-2.0 m and sampling was carried out four times a month for a period of 12 months. The adsorbed VOCs were desorbed with carbondi sulphide [CS2] and the solution analysed using Gas Chromatography [GC] fitted with Flame lonization Detector [FID]. Twenty-Six [26] VOCs were captured in the Atmosphere of each of the studied areas. The VOCs were classified thus: aromatics 37-42%, halogenated 37-38%, esters 2-3%, ketones 7-11%, alcohols 5-11%, ethers 4%, dienes 0-2%, nitrites 0-2%. Seven [7] VOCs each were the major contributors to ambient air pollution in Ikeja and Isolo industrial areas. VOCs pollutants in Ikeja industrial areas are xylenes 61.90%, Isopropy I benzene 20.90%, Isopropyl Acetate 8.47%, n-Butylhenzene 5.53%, Tuolene 1.34%, n-propyl-benzene 0.58% and methy-lene chloride 0.56% [eigen value > I] while in Isolo they are Ethylbenzene 66.36%, Ethanol 13.39%, chloroform 6.60%, 2,2 Dichloropropane 5.15%, xylene 3.89%, Isopropyl Acetate 1.77% and Tetra-chlo methane 1.66%. There is a significant difference [Pvalue < 0.05] between the levels of VOCs in the studied areas. The meteorological significant correlations with the ambient concentrations of VOCs. The monthly mean concentrations of the atmosphere total volatile organic compounds [TVOCs] in the studied areas show significant difference. The Principal Component Analysis [PCA] showed that the major sources of VOCs are mainly anthropogenic and four factors each were identified as sources of VOCs in each of the studied industrial areas with industrial emissions dominating in industrial areas