Phenyl Methyl Siloxane Research Articles

Multifunctional hybrid T-PI-MPS composite coating: Corrosion resistance, low-wear/friction and heat-resistance

Despite methylphenylsiloxane (MPS) possesses heat-resistance and corrosion resistance, the brittleness hinders its widespread application. Herein, the polyimide (PI) and Ti3AlC2 were introduced for modifying MPS, thereby preparing the T-PI-MPS coating. The bilayer structure of surface-enriched MPS and internal-enriched PI was achieved by controlling the addition amount along with the density difference. The results indicate that the T-PI-MPS coating achieved a contact angle of 95.1° and exhibited corrosion resistance to salt spray for 28 days. Compared to PI-MPS, the wear rate of T-PI-MPS was reduced by 85 % and the friction coefficient declined from 0.75 to 0.58. As expected, T-PI-MPS exhibited exceptional excellent heat-resistance. The exceptional performance is attributed to the following three factors: I. the MPS-enriched layer is characterized by a stable SiO chain organization. This structure gives the corrosion resistance and water resistance, and prevents the hydrolytic swelling of PI. II. the PI-enriched layer is constructed from imide bonds, which give the coating superior friction performance due to its high load-bearing capacity. III. the incorporation of Ti3AlC2 plays a role in mitigating internal defects, prolonging the corrosion path, and inhibiting cracks due to its unique nanolayered structure, high temperature resistance, and hardness.

Microplastics in commercial fish digestive tracts from freshwater habitats in Northern Thailand

Microplastics (MPs) contamination in fish species was one of the emerging environmental issues as a result of the widespread presence of plastic pollution in the environment. The presence of MPs in Thailand's freshwater was scant, and in contrast to other countries, little was known about the presence of this contaminant in freshwater fish. Hence, the purpose of this study was to examine the abundance, characteristics, and variation of MPs in various Thai commercial freshwater fish species. In order to compare the differences in MP ingestion rates across different feeding zones, 166 fish representing 24 species from various feeding zones were collected. MPs were found in the gastrointestinal tracts (GIT) of all fish samples tested, which was a substantially larger number than previously reported in other locations. Of all the fish species, Anabas testudineus, Labeo rohita, and Oreochromis mossambicus had the highest concentration of MPs (34.90 ± 21.43, 34.50 ± 7.78, 34.10 ± 11.15 items/individuals). Microscopical examinations showed that the majority of MPs were fiber-shaped and blue in color. Fourier transform infrared analysis (FTIR) showed that the polymers found in fish GIT were polyethylene, polypropylene, polyethylene terephthalate, polyvinyl acetate, poly (methyl vinyl ether), poly (methyl vinyl ether), polybutadiene, poly (ethylene-co-propylene), poly (ethylene glycol) tetrahydrofurfuryl ether, poly (methyl phenyl siloxane), poly (styrene-co-divinylbenzene), and polyvinylidene fluoride. The results of this study demonstrate that demersal fish had a higher concentration of MPs than benthopelagic and pelagic fish, indicating that plastic ingestion in fish may be related to the feeding habitat. However, it was not discovered that differences in the fish's body weight and length affected the MPs' ingestion. Our findings will help people in Thailand understand which freshwater fish and fish from which feeding zones are more contaminated with MPs for human consumption.

Gas Chromatography Mass Spectroscopy (GCMS) Qualitative Analysis for Morphine, Heroin and Codeine used in Doping

Three types of doping drugs, morphine, heroin, and codeine were analyzed qualitatively in urine using GCMS: HP5MS column containing a nonpolar substance, phenylmethyl siloxane, with a temperature range of 90-250ºC and a rate of increase of 10ºC/minute. Diethyl ether was used to extract morphine, codeine, and heroin. The extractions were performed at pH 8, the organic phase was evaporated, followed by derivatization. Morphine and its derivatives were treated with a solution of N-methyl-N-trimethylsilyl-trifluoroacetamide and N-methyl-bis-trifluoroacetamide. The results of the gas chromatographic analysis showed that the retention times of morphine, heroin, and codeine the retention times were 8.01, 7.32, 6.21 minutes, while those of their derivatives were 8.10, 8.10, 7.95 minutes respectively. The identification of each drug using mass spectrometry revealed that their mass spectra were identical to the standard. The mass spectra of the derivatives: morphine-TMS and codeine-TMS showed a resemblance index of 93% respectively compound to the standard, with a detection limit of 2 ug/ml.

Effect of the Surface Polarity, Through Employing Nonpolar Spacer Groups, on the Glass-Transition Dynamics of Poly(phenyl methylsiloxane) Confined in Alumina Nanopores

Broadband dielectric spectroscopy and differential scanning calorimetry were used to study the effect of changes in the surface conditions on the segmental dynamics of poly(phenylmethylsiloxane) confined in alumina nanopores. Functionalization was done using highly polar propyl phosphoric units separated by the assumed concentration of triethoxysilane groups (from N = 0 to N = 24). By adjusting the proportion between polar units and nonpolar spacers, it was possible to control the surface polarity. Modification of the surface conditions does not inhibit the formation of the adsorbed layer, as revealed by the presence of two Tg’s in calorimetric results. However, changes in the surface polarity will prevent the growth of the additional interlayer in between the core volume and the interfacial layer. Finally, we also found that the changes in the surface polarity affect the equilibration kinetics and can be used to control the time scale of the structural recovery toward the equilibrium state.

Selective and Sensitive Quantification of Acetochlor and S-Metolachlor in Maize and Soybean Plant Samples by Gas Chromatography-Tandem Mass Spectrometry

Herbicide residue analysis has gained importance worldwide, mainly for food quality control to minimize potentially adverse impacts on human health. A Gas chromatography-tandem mass spectrometry (GC-MS) method for quantitative analysis of acetochlor and s-metolachlor in maize and soybean straw has been developed, validated and applied to analyze the residues of anilide herbicides. Straw material was dried, homogenized and extracted with a mixture of n-hexane and acetone by an accelerated solvent extraction method. Chromatographic separation of the target analytes was performed on an Agilent 7832 GC equipped with a mass spectrometer detector, a split-splitless injector and an HP-5 MS (5% phenylmethyl siloxane) capillary column (30 m × 0.25 mm × 0.25 µm). Under these parameters, the limit of detection (LOD) values were 0.2 ng g−1 for acetochlor and 0.07 ng g−1 for s-metolachlor, with average recoveries between 86% and 119.7%. The method was validated for acetochlor and s-metolachlor in maize and soybean straw at 0.5 and 0.01 mg kg −1. Furthermore, the final residues of the two herbicides in maize and soybean straw were below the maximum residue limit (MRL) at harvest time. The proposed method is suitable for routine analysis.

US FDA-validated green GC-MS method for analysis of gabapentin, tramadol and/or amitriptyline mixtures in biological fluids.

Background: Mixtures of gabapentin, tramadol and/or amitriptyline are usually recommended for treatment of neuropathic pain. Materials & methods/results: A novel GC-MS/MS method was developed to assess the studied mixture whether in pure forms or human biological fluids (plasma/urine). The chromatographic detection was performed using MS detector applying the selected ion-monitoring mode. An (Agilent, CA, USA)GC-MS with triple axis single quadrupole detector unit was used for the analysis equipped with HP-5MS (5% phenyl methyl siloxane) column. Helium was the carrier gas and positive electron impact ionization mode was applied. Conclusion: The developed method was able to assess the mixture components simultaneously within six minutes. Validation of the method was assured according to USFDA guidelines and Eco-Scale assessment.

The Impact of the Molecular Weight on the Nonequilibrium Glass Transition Dynamics of Poly(Phenylmethyl Siloxane) in Cylindrical Nanopores

Changes in the glass transition dynamics caused by the nanoconfinement reveal pronounced out-of-equilibrium features. Therefore, the confinement effects weaken with time. Using the Dielectric Spect...

Effect of Surface Chemistry on the Glass-Transition Dynamics of Poly(phenyl methyl siloxane) Confined in Alumina Nanopores.

Broadband dielectric spectroscopy (BDS) and differential scanning calorimetry (DSC) are combined to study the effect of changes in the surface chemistry on the segmental dynamics of glass-forming polymer, poly(methylphenylsiloxane) (PMPS), confined in anodized aluminum oxide (AAO) nanopores. Measurements were carried for native and silanized nanopores of the same pore sizes. Nanopore surfaces are modified with the use of two silanizing agents, chlorotrimethylsilane (ClTMS) and (3-aminopropyl)trimethoxysilane (APTMOS), of much different properties. The results of the dielectric studies have demonstrated that for the studied polymer located in 55 nm pores, changes in the surface chemistry and thermal treatment allows the confinement effect seen in temperature evolution of the segmental relaxation time, τα(T) to be removed. The bulk-like evolution of the segmental relaxation time can also be restored upon long-time annealing. Interestingly, the time scale of such equilibration process was found to be independent of the surface conditions. The calorimetric measurements reveal the presence of two glass-transition events in DSC thermograms of all considered systems, implying that the changes in the interfacial interactions introduced by silanization are not strong enough to inhibit the formation of the interfacial layer. Although DSC traces confirmed the two-glass-transition scenario, there is no clear evidence that vitrification of the interfacial layer affects τα(T) for nanopore-confined polymer.

Ceramic coating formation during carbothermic reaction of polysiloxanes with carbon and graphite materials

Polysiloxane resins-derived ceramic precursors were used as a binder to manufacture polygranular carbon and graphite-based composite materials. Two types of poly[methyl(phenyl)siloxane]-based resins differing in the structure and O/Si and C/Si ratios were used. During controlled annealing the composite samples up to 2000 °C, the ceramic polymer precursors were transformed into amorphous silicon oxycarbide (SiOC) or nanocrystalline β-SiC (nc-3C) phase. Resins-derived ceramic residues obtained at 2000 °C formed a nanocrystalline layer surrounding graphite grains, whereas in the anthracite material the ceramic phase precipitated between the grains forming separated, single crystallites. The differences in morphology of the carbide compounds formed in the presence of anthracite and graphite grains resulted from the difference in their structural stability and from the nature of interfacial bonding formed at the early stage of composites preparation. Strong interfacial adhesion between the anthracite grains and the polysiloxane resin caused the formation of large cracks in the composite samples during their heating to 1000 °C. The oxidation resistance was higher for graphite-based composites compared to anthracite-containing samples.

Organosilicon resin-based carbon/ceramic polygranular composites with improved oxidation resistance

We examined the thermo-mechanical properties of carbon materials modified with silicon oxycarbide (Si-O-C) and silicon carbide (Si-C). These compounds were obtained by the impregnation of carbon components with a silicon-containing polymer resin. Graphite and anthracite powders were used as carbon components, and poly[methyl(phenyl) siloxane] resin (P) was used as the ceramic precursor. Carbon/polymer compositions (C/P) were subjected to two-stage annealing, first to 1,000 °C and next to 2,000 °C in an inert atmosphere, leading to the formation of C/Si-O-C and C/Si-C composite samples, respectively. The materials were then examined under conditions of isothermal oxidation to determine their oxidation resistance and the mechanical properties before and after oxidation tests. The structure of the samples before and after oxidation was studied. C/Si-C composites, despite their high porosity, proved to have enhanced resistance to oxidation at 600 °C, although they had lower mechanical properties in comparison to C/Si-O-C samples.

Analysis of underivatised low volatility compounds by comprehensive two-dimensional gas chromatography with a short primary column

Comprehensive two-dimensional gas chromatography (GC×GC) approaches with cryogenic modulation were developed for the qualitative analysis of selected low volatility compounds in raw coffee bean extracts, without derivatisation. The approaches employed short first (1D) and second (2D) dimension columns, specifically a 1D 65% phenyl methyl siloxane column (11m) and a 2D 5% phenyl methyl siloxane column (1m), which allowed elution of high molar mass compounds (e.g.>600Da). Solutes included hydrocarbons, fatty acids, diterpenes, tocopherols, sterols, diterpene esters, and di- and triacylglycerides. An oven temperature program up to 370°C was employed. The effects of experimental conditions were investigated, revealing that the GC×GC results strongly depended on the cryogenic trap T, and oven T program. An appropriate condition was selected and further applied for group type analysis of low volatility compounds in green Arabica coffee beans. Retention indices were compiled for 1D GC analysis and were similar for the composite column data in GC×GC. The elution of some compounds was confirmed by use of authentic standards. The approach allowed direct analysis of coffee extract in ethyl acetate solution, with improved analyte peak capacity (approximately 200 compounds were detected) without prior fractionation or pre-treatment of the sample. This avoided potential hydrolysis of high molar mass conjugate esters as well as degradation of thermally labile compounds such as the derivatives of the diterpenes cafestol and kahweol.

The thermal stability investigation of microencapsulated ammonium polyphosphate/siloxane‐modified epoxy resin composites

ABSTRACTIn this investigation, epoxy resin composites containing phosphate and silicone were prepared from microencapsulated ammonium polyphosphate (MFAPP) and poly(methylphenyl siloxane) (PMPS). Silicone‐containing epoxy (E‐S) copolymers were gained by the grafting reaction between OCH3 of PMPS and OH of E51. And, a fixed weight of MFAPP was introduced to epoxy systems via the physical blending method. The chemical structure of the E‐S copolymer was determined by Fourier transform infrared spectroscopy (FTIR) and 1H‐NMR. The impact testing results revealed that the impact toughness was improved slightly. The thermogravimetric analysis (TGA) results demonstrated that the thermal degradation property in high temperature region and solid residue yield at 800 °C were enhanced remarkably with increasing PMPS content, whether the testing atmosphere was in nitrogen or oxygen. Moreover, an obvious synergistic effect of silicon and phosphorus on promoting the thermo‐oxidative degradation stability and solid residue at 800 °C was proved. Furthermore, the scanning electron microscope micrographs and FTIR result of residual charred crusts of EA‐S systems after the TGA testing in air manifested that the bubbled charred layer and silicon‐ and phosphorus‐containing residue took chief responsibility for thermo‐oxidative degradation property and solid residue yield. So the MFAPP/siloxane‐modified epoxy resin composites have a significant development prospect in high‐temperature resistant organic adhesives and coatings. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45272.

Determination of agomelatine in urine in the presence of metabolites by gas chromatography-mass spectrometry (GC-MS)

Aim. Development and validation of the method for quantitative determination of agomelatine in urine in the presence of its metabolites using GC-MS.Methods. Chloroform was used to extract agomelatine from the urine samples, after sedimentation of uric acids by Calcium chloride. Identification and assay of the extracted agomelatine was carried out using Agilent 6890 N chromatograph with 5978 BMSD (Agilent technologies, USA) mass spectroscopy detector. Restek Rtx-5 (USA) column with 5% phenyl methyl siloxane (30m×0.25mm;0.25μm) was used for separation of the components. Carrier gas was helium. Mass detection was performed during 70 eV electronic ionization and 400 V voltages. Scanning was carried out in Scan mode within 50-550 u.Results. The developed method for agomelatine determination was validated in agomelatine linear concentration range 40-6000 ng/ml with the correlation coefficient 0.99975. The method is correct and reproducible by all parameters in the linear range of concentrations according to OECD/WHO GLP requirements, and FDA, EMA and Ministry of Health of Ukraine recommendations.Conclusion. 15 ng of agomelatine can be identified in 1 ml of urine, and 40 ng of it can be quantified by the displayed method. The total content of the detected metabolites on agomelatine concentration was approximately 35.0%. The developed method is characterized by implementation simplicity, accuracy and reproducibility, and it can be used for chemical and toxicological analysis of agomelatine

Determination of Organochlorine Pesticides in Sediments Using Gas Chromatography and Mass Spectrometry

Seventeen Organochlorine Pesticides (OCPs) were evaluated in 14 surface sediment samples from a dam lake in Northwestern Turkey. As analytical tool GC-Mass system; HP (Hewlett Packard) 6890 series gas chromatograph coupled with HP 5973 mass spectrometer was used. The HP 5MS capillary column had 30 m length with 0.32 mm internal diameter. A 0.25 mm film thickness cross-linked with stationary phase of 5% Phenyl methyl siloxane and Ultra-pure Helium gas was used as mobile phase. Ultrasonic bath extraction method was applied and cleaned up process were carried up with anhydrous Na2SO4 and Florisil column. Total pesticides concentrations were ranged from=0.237-2.39 mg/kg for dry weıght. Percent total organic carbon (TOC) were observed between 1 and 3%. Average total OCP concentrations was 58.00 ± 45.44 mg/kg. The total concentrations of OCPs in sediment samples ranged from 12.9 to 169.9 mg/kg, with a mean value of 58.00 mg/kg. Although organochlorine pesticides have been banned in Turkey still the residues can be seen in sediment samples indicating the use of prohibited pesticides in the country. Comparison of organochlorine pesticides concentrations in sediment samples with other lakes in Turkey implies the higher concentration therefore higher usage of synthetic chemicals.

Noncovalently functionalized multi-walled carbon nanotube with core-dualshell nanostructure for improved piezoresistive sensitivity of poly(dimethyl siloxane) nanocomposites

Poor sensitivity in low pressure regimes (<100kPa) of pressure-sensitive rubbers (PSRs) is one of their major disadvantages compare to other piezoresistive materials. The reasons induced the poor sensitivity include bad dispersion and week interface of multi-walled carbon nanotubes (MWCNTs) applied in poly(dimethyl siloxane) (PDMS). A novel vinyl-terminated poly(dimethyl siloxane)-poly(phenylmethyl siloxane)-multi-walled carbon nanotubes (V-P-MWCNTs) with core-dualshell nanostructure is fabricated by noncovalently functionalized method. The V-P-MWCNTs as conductive fillers exhibits homogenous dispersion as well as good interfacial interaction in PDMS matrix. Slightly above the percolation threshold (0.19vol.%), the PDMS-based nanocomposites with 0.2vol.% of V-P-MWCNTs shows high piezoresistive sensitivity (22.16×10−3kPa−1), high electrical conductivity (5.43×10−3S/m) and low Young’s modulus (288.83kPa). These results demonstrate that the V-P-MWCNTs are of great potential as the conductive fillers for improved piezoresistive sensitivity of PDMS nanocomposites, which can be potentially applied in the flexible touch sensors.

Use of nicotinamide as an internal standard for gas chromatographic quantitation of heroin in illicit forensic drug seizures in Pakistan

A precise and economical method using nicotinamide as an internal standard for the quantitation of heroin in illicit forensic drug seizures in Pakistan was developed and validated by gas chromatography coupled with a flame ionisation detector. The retention time of heroin hydrochloride was 6.06 ± 0.2 min using a HP-5 (5% phenyl methyl siloxane) column and 99.9% nitrogen carrier gas. The method showed good linearity (r2 = 0.9986) in the range of 0.05–95 mg/ml of heroin hydrochloride. Limits of detection and quantitation were 0.02 mg/ml and 0.05 mg/ml of heroin hydrochloride respectively. Accuracy at three concentrations (20, 50 and 95 mg/ml) ranged from 97–103% and precision ranged from ±1.2–2.5% CV. Forty-five samples seized by the Anti-Narcotics Force of Pakistan were analysed and adulterants were also identified. The proposed method is economic, rapid and involves very little sample preparation, facilitating high throughput that can also be employed for detection of adulterants in heroin seizures.

Inelastic neutron spectroscopy as a tool to investigate nanoconfined polymer systems

Abstract The effect of a nanometer scale confinement (pore sizes 7.5 nm down to 2.5 nm) on the vibrational density of states (VDOS) and on the molecular dynamics of Poly(dimethyl siloxane) (PDMS) and Poly(methyl phenyl siloxane) (PMPS) is studied by inelastic neutron scattering. The high penetration depth of neutrons makes neutron scattering a suitable tool for the study of confined systems. Moreover, neutrons are sensitive to light nuclei therefore the confined polymers can be investigated directly, more or less independently of the confining host. Resulting findings are firstly, a reduction of the low frequency contributions to the VDOS below the Boson Peak frequency for both polymers. Including literature data, this reduction can be regarded as a more general feature for glass-forming systems confined by hard walls. Secondly, clear deviations in the temperature dependence of the mean squared displacement of the confined molecules compared to the bulk were found close to the thermal glass transition temperature, whereas localized methyl group rotations were only weakly influenced. Furthermore, the molecular dynamics is accessed. The combination of neutron Time-of-Flight with neutron backscattering, thus covering a broad dynamical range from sub ps to ns, reveal clear influence from confinement on the intermediate incoherent scattering function S(q,t). The latter was obtained by combining the inverse Fourier transform of the individual dynamical structure factors measured by the both methods. The time and q dependence of S(q,t) are discussed in detail for the local methyl group rotations and the segmental dynamics, considering both the interaction of the segments with the pore walls and possible geometrical confinement effects.

Chemical Constituents of the Essential Oil of Galium mite var. roseum ghahramaninejad from Iran

The genus Galium belongs to the family Rubiaceae. Some species of the genus have been reported to possess antispasmodic, diuretic, and vulnerary effects [1]. Plants of this genus are used for fermenting milk to cheese, and, due to this utility, the plant has been named Shir-panir in Iranian culture. The aerial parts of Galium species are also added to different types of food as herb or spice to improve the flavor. Galium mite var. roseum ghahramaninejad is distributed in Turkey, Iraq, Transcaucasus, and Iran. G. mite Boiss. & Hohen. and G. subvelutinum ssp. mite (Boiss. & Hohen.) Ehrend are the other names for the plant [2]. The chemical constituents of the essential oil of G. hercynicum, G. humifusum, G. salicifolium, and G. verum as members of the Galium species have been investigated before [3–5]. In the present work, the chemical composition of the essential oil of G. mite var. roseum ghahramaninejad is reported for the first time. To our knowledge, no previous phytochemical study has been performed on the essential oil of G. mite var. roseum ghahramaninejad. The plant material was collected in August 2012 from the Dena region of Iran and identified at the Department of Phytochemistry, University of Yasouj (Iran). Voucher specimens were deposited at the Herbarium of the Yasouj University, Yasouj, Iran (No. HYU25517). The aerial parts were air-dried at ambient temperature in the shade and hydrodistilled using a Clevenger-type apparatus for 4 h. The essential oil was obtained from the aerial parts of G. mite var. roseum ghahramaninejad as a yellow liquid in 0.1% (w/w) yield. The essential oil was analyzed by GC-MS (60–240 C at 3 C/min rate) in an Agilent Technology 7890A GC coupled to a 5975C-MS instrument using an HP-5MS capillary column (phenyl methyl siloxane, 30 m 0.25 mm; 0.25 m film thickness). The injector temperature was 240 C; injection was in the split mode (1:50). Helium was used as carrier gas at a flow rate of 0.9 mL/min. MS spectra were obtained using electron impact at 70 eV with a scan interval of 0.5 s and mass range from 35 to 550 m/z. The GC/MS analysis of the essential oil resulted in 38 compounds, making up 87.4% of the total composition. The most abundant constituent of the oil was borneol (18.0%), followed by aliphatic aldehydes, including n-nonanal (7.5%), (2E)-undecanal (7.0%), and (2E,4E)-decadienal (6.1%). According to Table 1, the volatile oil contained 12 aldehydes (42.1%), eight oxygenated monoterpenes (26.6%), five ketones (8.6%), three oxygenated sesquiterpenes (3.5%), six alkanes (2.2%), and three sesquiterpenes (1.8%). Unlike other reported species of Galium genus, the essential oil of G. mite var. roseum ghahramaninejad contained significant amounts of aliphatic aldehydes.

Study of Organochlorinated Pesticide Residues and Polychlorinated Biphenyls in Soil Samples

This paper presents and discusses the data obtained for organochlorinated pesticides and their residues in the soil samples of agricultural areas. Soil contamination is one of most important factors influencing the quality of agricultural products. Usage of heavy farm equipment, the land drainage, an exces­sive application of agrochemicals, emissions originating from mining, metallurgical, and chemical and coal power plants and transport, all generate a number of undesired substances (nitric and sulphur oxides, PAHs, heavy metals, pesticides), which after deposition in soil may influence crop quality. Thus, input of these contaminants into the environment should be carefully monitored. Levels of organochlorinated pesticides contamination were evaluated in agriculture areas that are in use. 10 soil samples were taken in agricultural areas Plane of Dugagjini , Kosovo. Representa­tive soil samples were collected from 0-30 cm top layer of the soil.In the analytical method we combined ultrasonic bath extraction and a Florisil column for samples clean-up. The analysis of the organochlorinated pesticides in soil samples was performed by gas chromatography technique using electron capture detector (GC/ECD). Optima-5 (low/mid polarity, 5% phenyl methyl siloxane 60 m x 0.33 mm x 0.25μm film) capillary column was used for isolation and determination of organochlorinated pesticides. Low concentrations of organochlorinated pesticide and their metabolites were found in the studied samples. The presence of organochlorinated pesticides and their residues is probably resulting of their previous uses for agricultural purposes.

Chemical Investigations of the Essential Oils of Some Artemisia species of Ethiopia

The compositions of the areal parts of essential oils of Artemisia abyssinica, A. absinthium (Ariti), and A. annua have been studied. The oils were examined by GC, GC/MS, 1 HNMR, and 13 CNMR techniques.The total constituents of the oils 59%, 56%, and 44% have been identified from A. abyssinica, A. absinthium(Ariti), and A. annua respectively. The major components were yomogi alcohol and artemisia alcohol acetate for A. abyssinica; camphor,davanone and chamazulene for A. absinthium and camphor for A. annua. Four compounds were isolated from A. abyssinica and A. absinthium and their structure were elucidated based on spectroscopic 13 CNMR sophisticated techniques. The identification and percentage composition of the essential oils was computed from GC and GC/MS peak areas. Qualitative analysis was based on comparison of retention times with the standard or isolated compounds and the corresponding data in the literature (2, 6, 8, 9) GC analysis of the essential oils were performed using an instrument (Model: - HP6890 GC, coupled with an auto sampler) equipped with a capillary column HP-5 (5%phenyl methyl siloxane), 30.0 m x 320 µm i.d., film thickness 0.25µm. Nitrogen was used as the carrier gas at a flow rate of 0.8 ml/min. The oven temperature was held at 50 0 C, and then programmed to 210 0 C at a rate of 3 0 C/min. The injection and FID temperatures were kept at 210 0 C and 270 0 C, respectively. The essential oils isolated by steam distillation of the areal parts of A. abyssinica, A. absinthium ( Ariti)and A. annua . Yield and color of the oils were summarized in Table-1.