Injector Temperature Research Articles

Improving the method of determining wax-like substances in vegetable oils using high-temperature gas-liquid chromatography

The article defines the scientific approaches regarding the improvement of the standardized method of determining wax-like substances using high temperature gas-liquid chromatography. Experimental studies matched the type of capillary column, type of stationary phase, the composition eluent and the feed rate, temperature parameters of the chromatographic separation. The results of the monitoring of sunflower oil with different content of wax-like substances have confirmed the ability of the method. The possibility of qualitative identification of waxes by using chromatographic profiles is shown. Process conditions of the chromatographic analysis were established. There are gradient programming thermostat and temperature, the optimal injector temperature, composition and feed rate eluent (1 drop/s); selected internal standard – hexatriene (paraffin C36). The result of the monitoring of sunflower oil with different content of the waxes is shown that the improved method of determining wax-like substances is reliable and can be recommended for technical control of raw materials and finished products in the production of refined oils. It is experimentally confirmed that in the presence of external standard (sunflower wax) wax-like substances in vegetable oils is possible qualitative identify by comparison of the chromatographic profiles of the standard and sample.

Determination of Triethylamine, Pyridine and Dimethyl formamide content in Telmisartan by Headspace Gas chromatography using Flame Ionization Detector

Triethylamine, pyridine and dimethyl formamide are used as solvents in the synthesis of telmisartan. A simple, accurate and precise analytical method for determination of triethylamine, pyridine and dimethyl formamide in telmisartan was developed on headspace gas chromatography. The sample was dissolved in N-methyl pyrrolidone. Headspace vials of standard size and volume of 20 ml capacity were used for the study. The vials were incubated at 100°, for 20 min. Injection volume of headspace in to the gas chromatograph was 1 ml. The syringe temperature was maintained at 110°. The injector and detector temperature were 200° and 250°, respectively. Nitrogen gas was used as carrier gas with flow rate of 1 ml/min. Split ratio was 1:10. DB624 column with 30 m × 0.32 mm i.d., 1.8 µm film thickness was used. Column oven temperature was maintained at 40° for 15 min, followed by an increase up to 240° with the rate of 30°/min. The final temperature of the column with 240° was maintained for 5 min. This analytical method was validated with respect to precision, linearity, recovery, limit of detection and limit of quantification.

Determination of Dimethylamine and Triethylamine in Hydrochloride Salts of Drug Substances by Headspace Gas Chromatography using Dimethyl Sulphoxide- imidazole as Diluent

A simple, rapid, accurate and precise analytical method for determination of secondary and tertiary amines in hydrochloride salt form of drug substances in non aqueous medium, which does not require any derivatization, was developed by headspace gas chromatography. Dimethylamine hydrochloride and triethylamine hydrochloride were analyzed in metformin hydrochloride. The sample was dissolved in a vial containing dimethyl sulphoxide and imidazole. The vials were incubated at 100o, for 20 min. The syringe temperature was maintained at 110o. DB624 column with 30 m×0.32 mm i.d., 1.8 µm film thickness was used. The injector and detector temperature were 200° and 250°, respectively. The analytical program used was carrier gas (nitrogen) flow rate: 1 ml/min; injected gas volume: 1.0 ml; split ratio: 1:10; oven temperature program: 40o for 10 min, followed by an increase up to 240° at 40o/min. The analytical method was validated with respect to precision, recovery, limit of detection and quantification and linearity.

Validation of an enantioselective analysis for (l)-pidolic acid by chiral gas chromatography with derivatization

A sensitive and rapid analytical method has been validated for the enantiomeric purity determination of l-pidolic acid, a biological lactam and metabolite of glutamic acid commonly found in urine, skin, bones, brain and is available commercially as a food supplement. An efficient, two-step achiral derivatization was implemented which consisted of an alkylation step (using HCl-IPA) followed by an acylation step (using TFAA) of the carboxy and amide functional groups. This allowed detection with high sensitivity using gas chromatography with flame ionization detection. The described procedure employs a CP-Chiralsil-L Val column (25m×0.25mm) at a constant flow rate of 1.5mLmin−1, a gradient temperature program from 80°C to 160°C and an injector and detector temperature of 250°C. The proposed method was validated according to ICH Q2 standards and included such parameters as specificity, system precision, analyst repeatability, intermediate precision, accuracy, linearity, LOD/LOQ and solution stability.

Chemical Composition of Leucas Stelligera

oxygenated monoterpenes (5.9%), and monoterpene hydrocarbons (5.5%). The major components of the oil were -caryophyllene (18.2%), -elemene (13.5%), -gurjunene (8.7%), trans--bergamotene (4.9%), and -selinene (3.6%). Plant Material and Isolation Procedure. The aerial parts of Leucas stelligera were collected in November 2012 from Amboli, Maharashtra, India. A voucher specimen (RMRC-554) has been deposited in the herbarium of Regional Medical Research Centre, Belgaum. The oil was obtained by hydrodistillation of fresh aerial parts of this species using a Clevenger-type apparatus for 3 h. The yield of oil was 0.3% (w/w). The oil was dissolved in n-hexane, dried over anhydrous sodium sulfate, and stored at –4C. Identification of the Oil Components. The oil was analyzed using a Varian 450 chromatograph with a CP-Sil 8 CB capillary column (30 m 0.25 mm; 0.25 m film thicknesses) with an FID under the experimental conditions reported earlier [2] and a Thermo Scientific Trace Ultra GC interfaced with a Thermo Scientific ITQ 1100 mass spectrometer fitted with a TG-5 MS (Thermo Scientific) fused silica capillary column (30 m 0.25 mm; 0.25 m film thicknesses). The oven temperature 60–220C was programmed at 3C/min using helium as carrier gas at 1.0 mL/min. The injector temperature was 230C; injection volume 0.1 L; sample prepared in n-hexane; split ratio 1:50. Mass spectra were taken at 70 eV with mass range 40–450 m/z, and characterization was done on the basis of the retention index, by the MS Library Search (NIST and Wiley), and by comparison with the mass spectral data [3].

Chemical Composition of Essential Oils from Piper Kadsura

Piper kadsura (Choisy) Ohwi belongs to the Piperaceae family and grows in Fujian and Hainan, with other sporadic distributions in southern China [1]. Its stem, known as a haifengteng, is used in traditional Chinese medicine to treat asthma, anemofrigid-damp arthralgia, and traumatic injury [2]. Piper kadsura shows cytotoxic and anti-neuroinflammatory [3, 4], and anti-inflammatory [5] activitiess it regulates cell proliferation, gene expression, production of cytokines, and cell cycle progression in primary human T-lymphocytes [6]. Phytochemical studies on plants of Piper kadsura have yielded various types of compounds such as lignans, neolignans, amides, terpenes, cyclohexanes, alkaloids, flavonoids, epoxides, sterols, and volatiles [7–14]. We report here the results of our studies on the composition of the essential oil from the dried stem of Piper kadsura. The fresh stems of Piper kadsura (Choisy) Ohwi were collected from Fu Xing Hou Medicinal Materials Company, Gansu Province, China. The plant stem sample was identified by Prof. Qi Huanyang, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences. A voucher specimen is deposited in the Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences (No. 02010182). The essential oil was obtained by hydrodistillation using a Clevenger-type apparatus for 5 h, yielding 0.15% (v/w) oil. The essential oil was dried over anhydrous sodium sulfate and studied by GC-MS. The essential oil was subjected to gas chromatographic/mass spectral analysis using an Angilent HP6890 GC with an Agilent 5973I mass selective detector. The analytical conditions included an SE-54 (50 m 0.25 mm 0.50 m) quartz capillary chromatography column, carrier gas: helium with flow rate 1.2 mL/min; volume injected: 0.4 L; split ratio:30:1; initial column temperature 60 C for 2 min, and then programmed to 140 C at a rate of 15 C min–1, finally programmed to 260 C at a rate of 8 C min–1 and held for 10 min; injector temperature 250 C; electron ionization mass spectra were acquired over the mass rage of 40–400 amu; ionization voltage 70 eV; The ion source temperature was at 230 C. The transfer line was at 280 C. Constituents of the oil were identified by comparing the mass spectra of the products with data in the NIST02.L mass-spectra library. The relative percentage amounts of the separated compounds were calculated automatically from peak areas of the total ion chromatograms (TIC). The identified components and their percentages are given in Table 1, where the components are listed in the order of their elution on the column. Forty-three components were detected in the oil, representing 72.01% of the total oil. As can be seen, the major components of the oil are -eudesmol (12.9%) and laevojunenol (9.8%). The contents of espatulenol, -caryophyllene, cis-asarone, and valencene were 6.0%, 6.0%, 5.8%, and 5.4%, respectively.

Composition and Antibacterial Activity of the Essential Oil of Phlomidoschema parviflorum from Iran

The monotypic genus Phlomidoschema Vved. belongs to the family Lamiaceae, subfamily Lamioideae and tribe Stachydeae [1]. Phlomidoschema parviflorum (Benth.) Vved. grows in restricted parts of Iran (Khorasan Province) as well as Afghanistan, west of Pakistan, Pamir Mountains, and Punjab of India. Morphologically, the species is characterized by perennial, multi-stemmed and subshrub habit and white subfloccose and canescent hairs on the leaves and stem [2]. The species is considered vulnerable and rare according to IUCN categories [3]. The infusion of the aerial flowering part of the plant is used locally for the treatment of gastrointestinal disorders, colic and stomachache. From the phylogenetic point of view, the genus is closely allied with the genus Stachys. The most relative and closest species of the genus Stachys to the genus Phlomidoschema was found to be S. lavandulifolia Vahl. [1]. As far as our literature survey could ascertain, there is no report on the oil composition and biological activity of P. parviflorum. So, in continuation of our research on the composition and biological activity of Iranian aromatic and essential oil-bearing plants of the mint family [4–10], we have investigated the composition and antibacterial activity of the essential oil of P. parviflorum. The aerial full flowering parts of Phlomidoschema parviflorum were collected from Khorasan-e Razavi Province, Ghayen towards Gonabad, Zirkuh region with an altitude of 1300–1350 m. A voucher specimen was identified and deposited (MPH-1220) in the Medicinal Plants and Drugs Research Institute Herbarium (MPH), Shahid Beheshti University of Tehran, Iran. Air-dried aerial parts (200 g) were subjected to hydrodistillation for 3 h using a Clevenger-type apparatus. The oil was dried over anhydrous sodium sulfate and stored in sealed vials at 4C until analysis and tested. GC analysis was carried out on a Thermoquest-Finnigan Trace GC instrument equipped with a capillary DB-5 fused silica column (60 m 0.25 mm i.d., film thickness 0.25 m). The oven temperature was raised from 60C to 250C at a rate of 5C/min, then held at 250C for 10 min. Nitrogen was used as the carrier gas at a flow rate of 1.1 mL/min; the split ratio was adjusted to 1:50. The injector and detector (FID) temperatures were kept at 250C and 280C, respectively. GC-MS analysis was carried out on a Thermoquest-Finnigan Trace GC-MS instrument equipped with a DB-5 fused silica capillary column. Helium was used as the carrier gas at a flow rate of 1.1 mL/min with a split ratio of 1:50. The quadrupole mass spectrometer was scanned over 45–465 amu with an ionizing voltage of 70 eV. Gas chromatographic conditions were the same as given above for GC. The constituents of the oil were identified by calculation of their retention indices under temperature-programmed conditions for n-alkanes (C 6 –C 24 ), and the essential oil on a DB-5 column. Identification of individual compounds was made by comparison of their mass spectra with those of the internal reference mass spectra library or with authentic compounds and confirmed by comparison of their retention indices with those reported in the literature [11]. In vitro antibacterial activity of the essential oil was assessed against Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922 as models of Gram positive and Gram negative bacteria, respectively. The broth microdilution susceptibility method using 96 well trays was used to determine the minimum concentration of essential oil required for inhibition of visible growth (MIC) or killing (MBC) of the test strains. For this purpose, the standard protocol of CLSI (Clinical Laboratory and Standards Institute) was used with some modifications [12]. The inoculants of the bacterial strains were prepared from freshly cultured strains using sterile normal saline, which were adjusted to 0.5 McFarland standard turbidity and then further diluted (1:1000 for bacteria) by sterile Mueller-Hinton broth (MHB) just before adding to the wells containing a desired range of diluted essential oil.

Method development and validation of arene substituted regioisomers in a pharmaceutical candidate by high temperature GC-FID

This paper describes the development and validation of a high temperature gas chromatography flame ionization detection (HTGC-FID) method for the purity evaluation of arene substituted regioisomers in a key starting material of a pharmaceutical candidate in Phase 3 studies. The chromatographic conditions of the method employ a (5%-phenyl)-methylpolysiloxane packed column (30m×0.25mm) at a constant flow of 1.0mLmin−1 with a gradient temperature program from 150°C to 400°C with injector and detector temperatures of 300°C and 340°C, respectively. The calibration curve for the desired product (r=0.9999) was assessed for five points in the range from approximately 1.0μgmL−1 to 40μgmL−1. The precision (% RSD) of the method was calculated for six replicate injections and found to be 0.81%. The limits of detection and quantitation were determined to be 0.06 and 0.20μgmL−1, respectively.

Determination of the content of residual solvents in Haikesu 2 by head-space gas chromatography.

To determine ethylacetate and petroleum ether(60-90 ℃)in Haikesu 2,which is one of the raw materials of artificial musk,using the head-space gas chromatography. The determination was performed on HP-5(30 m×0.53 mm,5 Μm)capillary column with an hydrogen flame ionization detector. The solvent was dimethyl sulfoxide and the internal standard was methanol. The injector temperature and the detector temperature were controlled at 180 ℃ and 250 ℃,respectively. The carrier gas was nitrogen. The containers of head-space injector were preheated at 90 ℃ for 15 minutes. The column temperature was programmed raised,which achieved baseline separation of the components. The results showed a good linear relationship for ethylacetate and petroleum ether(60-90 ℃)in their linearity range;and the limit of detection was 0.7 and 0.3 Μg/ml,respectively. The good precision and good average recoveries were satisfactory. The head-space gas chromatography is simple,rapid,and precise technique for the measurement of residual solvents in Haikesu 2.

Determination of the content of residual solvents in Haikesu I by head-space gas chromatography.

To explore the usefulness of head-space gas chromatography for the determination of methanol and ethanol in Haikesu I,a raw material of artificial musk. The determination was performed on HP-5(30 m×0.53 mm,5 Μm)capillary column with an hydrogen flame ionization detector. The solvent was dimethyl sulfoxide and the internal standard was acetone. The injector temperature and the detector temperature were controlled at 180 ℃ and 250 ℃,respectively. The carrier gas was nitrogen. The containers of head-space injector were preheated at 90 ℃ for 15 minutes. The column temperature was programmed raised,which achieved baseline separation of the components. The results showed a good linear relationship for methanol and ethanol in their linearity range;and the limit of detection was 0.8 and 1.0 Μg/ml,respectively. The precision and average recoveries were satisfactory. The head-space gas chromatography is simple,rapid,and precise technique for the measurement of residual solvents in Haikesu I.

Determination of the content of residual solvents in muscone by head-space gas chromatography.

To explore the usefulness of a head-space gas chromatography in the determination of residual solvents including methanol,ethanol,ethyl ether,and petroleum ether in muscone in artificial musk. The head-space gas chromatography was performed on HP-5(30 m×0.53 mm,5 Μm)capillary column with a hydrogen flame ionization detector. The carrier gas was nitrogen and the solvent was dimethyl sulfoxide. The injector temperature and the detector temperature were controlled at 180 ℃ and 250 ℃,respectively. The containers of head-space injector were preheated at 80 ℃ for 15 minutes. The column temperature was programmed raised,which achieved baseline separation of the components. The results showed a good linear relationship for methanol,ethanol,ethyl ether,and petroleum ether(60-90 ℃)in the range of each consistency; and the limit of detection was 0.8,1.0,0.1,and 0.3 Μg/ml,respectively. The precision and average recoveries were satisfactory. The head-space gas chromatography is simple,rapid,and precise technique for measuring residual solvents in muscone.

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.

Constituents of the Essential Oil of Euphorbia hebecarpa

The Euphorbiaceae is a large family of flowering plants including 300 genera and over 5000 species. Euphorbia is the largest genus in this plant family with about 2000 species [1]. The Iranian Flora consists of 70 species of Euphorbia, including 17 endemics, and the popular Persian name of the species is “Farfion” [2]. Euphorbia hebecarpa Boiss., endemic to Iran, is a perennial plant distributed mainly in the Zagros Mountains [3]. Latex of some species of Euphorbia has traditionally been used in the treatment of skin diseases, gonorrhea, migraines, intestinal parasites, and warts [4]. Phytochemical investigation of the genus revealed that many of its components are highly bioactive [5–7]. Diterpenoids are found in the majority of the genus with many different core frameworks such as jatrophanes, lathyranes, tiglianes, ingenanes, and myrsinols [8–13]. In addition, some Euphorbia species are known to possess significant anticancer [14, 15], antitumor [16, 17], antimicrobial [17, 18], and antioxidant [19, 20] activities. To the best of our knowledge, there is no published report on the composition of E. hebecarpa essential oil. However, cytotoxic and antimicrobial activities of the extracts of the plant have been reported [21]. The present work studies the chemical composition of the essential oil from the aerial parts of E. hebecarpa for the first time. The plant material was collected during the flowering stage from Baft, the Kiskan area, Kerman Province, Iran in June 2012. A voucher specimen (No. 1136) has been deposited in the Herbarium of the Department of Microbiology, Kerman Branch, Islamic Azad University, Kerman, Iran. The air-dried aerial parts of the plant (100 g) were crushed and subjected to hydrodistillation for 3 h using a Clevenger-type apparatus. The clear yellowish oil was isolated in a yield of 0.2% (w/w). The constituents of the oil were analyzed by GC and GC-MS. GC analysis of the volatile components was carried out using a Hewlett-Packard 6890 instrument coupled to a flame ionization detector (FID). Compounds were separated on an HP-5 capillary column (30 m 0.25 mm, film thickness 0.25 m). The column temperature was kept at 60 C for 3 min and programmed to 220 C at a rate of 5 C/min. Injector and detector temperatures were 270 C, and the flow rate of helium as carrier gas was 1 mL/min. The percentage composition of the individual components was computed from the GC-FID peak areas without the use of correction factors. GC-MS analysis was performed using an Agilent 5975C mass spectrometer coupled to an Agilent 7890A gas chromatograph equipped with an HP-5MS capillary column (30 m 0.25 mm, film thickness 0.25 m). The carrier gas was helium, and the chromatographic conditions were as above. The spectrometer was scanned over the 40–400 amu range with an ionization voltage of 70 eV and an ionization current of 150 A. Retention indices were determined using the retention times of n-alkanes, injected after the essential oil under the same chromatographic conditions. The chemical compounds, which were identified on the basis of their mass spectral characteristics and retention indices [22], are listed in Table 1. As is shown, 28 components were identified in the essential oil, representing 97.6% of the total oil. The main constituents were -bisabolol (31.2%), cis-cadin-4-en-7-ol (20.1%), trans-piperitol (8.6%), cis-p-menth2-en-1-ol (6.4%), and trans-p-menth-2-en-1-ol (6.2%). Oxygenated sesquiterpenes (59.3%) were the most abundant components in the oil. The essential oil of E. teheranica Boiss., endemic to Iran, was also rich in oxygenated sesquiterpenes, and elemol (57.5%) has been reported as the main constituent of the oil [23].

Chemical Composition of the Essential Oil of Geum rhodopeum

were collected in June 2010 at Prestojceva mahala (Cemernik Mountain-42 44 45.43N, 22 18 40.01 E, Elev. 1339 m). The plant material was authenticated by one of the authors (V. N. Randjelovic). A voucherspecimen, with the accession number 16680, is deposited at the Herbarium of the Department of Botany, Faculty of Biology,University of Belgrade – Herbarium Code BEOU.Oil was obtained from air-dried aerial parts of the plant with 0.01% (w/w) yield by hydrodistillation for 4 h using aClevenger-type apparatus. The oil analyses were performed simultaneously by gas chromatography (GC) and gaschromatography-mass spectrometry (GC-MS) systems. The GC analysis of the oils was carried out on a GC HP-5890 IIapparatus equipped with a split-splitless injector, an HP-5MS capillary column (30 m 0.25 mm, 0.25 m film thickness) withhelium as the carrier gas (1 mL/min), and FID. Operating conditions: injector temperature 250 C and interface temperature280 C, temperature program from 50 C (3 min) to 250 C at a rate of 3 C/min. Volume injected, 1 L of the oil in ether (0.5%).GC/MS analyses, under the same gas-chromatograph conditions, were performed on an Agilent Technologies apparatus,Model GS 6890N coupled with a mass selective detector MSD 5975C. The MS operating parameters were as follows: ionizationpotential 70 eV; ion source temperature 250 C; quadrapole 150 C, solvent delay 3.0 min, mass range 50–550 amu, Em voltage1435 V.Identification of the compounds was based on comparison of Kovats retention indexes (applying calibrated automatedmass spectral deconvolution and identification system software (AMDIS ver. 2.64) in combination with selective ion analysis(SIA) resolution method [11]), comparison with the spectral data from the available literature [12], and comparison of theirmass spectra to those from Wiley 275 and NIST/NBS libraries using various search engines. Relative retention indexes (RRI)were obtained by co-injection with an aliphatic C

The determination of GC-MS relative molar responses of benzene and biphenyl derivatives

The dependence of relative response factors on the carbon and chlorine atom number related to naphthalene has been investigated by using gas chromatography-mass spectrometry (GC-MS). The main goal of these investigations is to find some relationship between the GC-MS signal (peak area) and the test molecule chemical structure. By means of the knowledge of correlations of relative molar response, the quantitative analysis passes into easier and fewer reference materials are needed to investigate a sample having lot of component, because the sensitivities can be determined from the correlations studied in this paper. This is very important in daily analytical tasks, particularly for impurity profiling studies. Relative responses of some polychlorinated benzenes, polychlorinated biphenyls and n-alkylbenzenes are compared in the experiments. Linear correlation is found between the molecular structures of n-alkylbenzenes, i.e. the carbon atom number, and relative molar response. Relative molar responses of polychlorinated biphenyls also provided linear correlation taken as a function of chlorine atom number. Under given conditions, the increments of CH2 unit and chlorine atom number to the relative molar responses are 0.221 and 0.198, respectively. However, relative responses of polychlorinated benzenes showed diversity plotted against chlorine atom number, and their isomer compounds also gave various results according to the first ionization energy. The measurement conditions can influence the relative responses. The low injector temperature, the interface and the ion source temperature affected relative responses of high volatile compounds. However, when the parameters are kept under control, the results can become accurate and reproducible.

Composition of Essential Oil from Bunium incrassatum from Algeria

The flora of Algeria includes seven species of the plant genus Bunium, four of which are endemic [1]. Essential oils from Bunium species were studied several times [2–6]. The root extract of B. incrassatum afforded two coumarins, -sitosterol, sucrose, and oleic acid. The antimicrobial activity of the primary extract was assessed using agar diffusion. The results showed that the primary extract had highly promising antimicrobial activity against all test microorganisms, especially against fungal strains [7]. Table 1 presents the chemical composition of oils obtained from other Bunium species. B. persicum (Siyah zira, black cumin) is used in Central Asia, Iran, Afghanistan, and Pakistan as a caraway substitute [4–6]. However, information about the essential-oil composition of B. incrassatum has not been published. Essential oils from steam distillation of B. incrassatum collected in Souk Naamane district (eastern Algeria) were analyzed using GC and GC/MS. Table 1 presents the essential-oil composition. Oil from ground fruit (A) of B. incrassatum afforded 28 components (81.4%) including caryophyllene oxide (31.0%), (Z)-farnesene (8.7), -caryophyllene (7.2), and germacrene B (5.8) as the principal constituents of sample A. Oil from fruit-bearing branches (B) of B. incrassatum held 40 constituents (85.2%) including caryophyllene oxide (26.8%), nonacosane (11.6), germacrene B (7.7), -caryophyllene (5.8), (Z)-farnesene (5.1), caryophyllenol II (4.8), and spathulenol (2.5) as the principal constituents in sample B. Thickened branches (C) of B. incrassatum yielded 24 constituents (75.4%) including nonacosane (44.7%), spathulenol (5.3), eudesm-4(15),7-dien-1 -ol (4.4), caryophyllenol II (4.1), (Z)-farnesene (2.3), germacrene B (1.2), and -caryophyllene (1.0) as the principal constituents of sample C. Plant Material. Ground fruit, fruit-bearing branches, and thickened branches of B. incrassatum Batt. (Apiaceae) were collected in Souk Naamane district in Oum-El-Buoaghi province (eastern Algeria) in May 2012. The plant was defined by Dr. Amar Zellagui, instructor of the Department of Biology, University of Oum-El-Bouaghi. A control specimen is preserved in the herbarium of the Department of Biology at the university (Constantine city) under code number ZA 103. Essential Oil Production. Ground fruit and fruit-bearing and thickened branches were steam distilled for 3 h using a Clevenger apparatus in order to determine the percent contents and traces. GC and GC/MS Conditions. GC used an Agilent 6890N chromatograph. The FID temperature was 300°C. A duplicate auto-injection onto an identical column using identical working conditions was made in order to obtain the identical elution sequence for GC/MS analysis. GC/MS used an Agilent 5975 GC-MSD, an Innowax FSC column (60 m 0.25 mm, film thickness 0.25 mm), and He carrier gas (0.8 mL/min). The GC furnace temperature was maintained at 60°C for 10 min, programmed to 220°C at 4°C/min, held at 220°C for 10 min, and then programmed to 240°C at 1°C/min. The flow division was set at 40:1. The injector temperature was 250°C. The ionizing-electron energy was 70 eV. The m/z range was 35–450. Essential oil constituents were identified by comparing their relative retention times with those of authentic samples or by comparing their relative retention indices (RRI) with a series of n-alkanes. The identification used computerized matching with commercial (Wiley GC/MS Library, Adams Library, MassFinder 3 Library) and local (Bayer Library of Essential Oil Constituents) databases that were created using information for authentic compositions and known oil constituents in addition to MS data from the literature.

Composition and Antioxidant Activity of the Essential Oil of Thymus dreatensis from Algeria

Thymus genus (Lamiaceae) has been found to possess significant biological activities, including antimicrobial, antioxidant, spasmolytic, antitussive, bronchiolitis, antifungal, sedative, and rubefaciant [1–16]. Twelve species are distributed in Algeria [7], nine of them endemic. In continuation of our works on Lamiaceae essential oils [8–11], we present here the essential oil composition and the antioxidant activity of the endemic species Thymus dreatensis Batt. Extraction. The hydrodistillation in a Clenvenger-type apparatus of the aerial parts of Thymus dreatensis yielded 2.1% of a pale yellowish oil. GC Analysis. GC analysis was performed on a Hewlett Packard 6890 gas chromatograph equipped with an FID and HP-5MS capillary column (bonded and cross-linked 5% phenylmethylpolysiloxane 30 m 0.25 mm, film thickness 0.25 m). Operating conditions were as follows: carrier gas He with a flow rate of 2 mL/min; column temperature 60–275 C at a rate of 4 C/min; injector temperature 280 C; injected volume 0.1 mL of the oil; split ratio 1:50. GC/MS Analysis. The oil was analyzed by GC/MS using a Hewlett Packard 6890 mass selective detector coupled with a Hewlett Packard 6890 gas chromatograph, equipped with a FID and HP-5MS capillary column (bonded and cross-linked 5% phenylmethylpolysiloxane 30 m 0.25 mm, film thickness 0.25 m), under the same conditions as GC (column, oven temperature, flow rate of carrier gas). The MS operating parameters were as follows: ionization potential 70 eV; ion source temperature 200 C; resolution 1000. Identification of Components. Essential oil components were identified based on their retention indices (determined with reference to a homologous series of normal alkanes) and by comparison of their mass spectral fragmentation patterns with those reported in the literature [12, 13] and with authentic compounds. Thirty-five components were identified, representing 97.4% of the total oil. The major constituents of the oil were thymol (28.1%), -terpinene (18.7%), thymyl methyl ether (10.9%), p-cymene (8.8%), and linalool (5.0%). Compared with our previously reported essential oils of T. ciliatus, T. fontanesii, and Thymus numidicus [1, 14–16] which were high-thymol chemotypes, it seems that the composition of the present essential oil is different. Nevertheless, -terpinene was also mainly found in T. fontanesii oil (15.9%) [14] (Table 1). Antioxidant Activity. The antioxidant activity was evaluated using the -carotene-linoleic acid test system [17, 18]. -Carotene (0.5 mg) in 1 mL chloroform was added to 25 L of linoleic acid and 200 mg of Tween 40 emulsifier mixture. After evaporation of chloroform under vacuum, 100 mL distilled water saturated with oxygen was added, followed by vigorous shaking. Then 4.0 mL of this mixture was transferred into different tubes containing different concentrations of the sample. As soon as the emulsion was added to each tube, the zero time absorbance was measured at 470 nm using a spectrophotometer. The emulsion system was incubated for 2 h at 50 C. A blank devoid of -carotene was prepared for background subtraction. Vitamin E was used as standard.

Determination of Acrylamide and Acrolein in Smoke from Tobacco and E-Cigarettes

Acrylamide and acrolein are two short-chained hazardous compounds with neurotoxic, carcinogenic, and mutagenic effects. The aim of this paper is to describe a fast and simple procedure for simultaneous determination of both acrylamide and acrolein under standard conditions, suggest a suitable calibration protocol for custom analysis, and demonstrate its applicability to the analysis of gaseous products from, e.g., cigarettes, cigars, or electronic cigarettes. A gas chromatography–mass spectrometry (GC–MS) method was developed to quantify acrylamide and acrolein in smoke vapor from electronic cigarettes, tobacco cigarettes, and cigars. Nonionic and highly polar molecules with a low boiling point and molecular mass need a suitable derivatization method to achieve appropriate retention and selectivity on commonly used relatively nonpolar stationary phases and to enhance the molecular mass for easy MS detection. The derivatization of acrylamide and acrolein was carried out by a bromination method with elemental bromine. The dibromo derivatives were extracted into an organic solvent and following a dehydrobromination procedure the samples were injected into the GC–MS system. Important experimental parameters were varied, after which the bromination time was defined as 30 min, and the injector temperature and the starting temperature of gradient were set at 280 and 50 °C respectively. Acrolein was found in all tested samples, while acrylamide was detected only in smoke from normal tobacco. Possible mechanisms for the formation of these unsaturated compounds in the samples are discussed. After its validation the newly developed method was successfully and reliably applied to the analysis of both compounds. This short method provides an easy way to determine acrylamide and acrolein in gaseous samples.

Reducing Bubble Defect on the Outsole Production Process in the Footwear Manufacturing Industry

The purpose of this study is to discover the significant factors causing the bubble defect on the outsoles manufactured by the Case Company. The bubble defect occurs approximately 1.5 per cent of the time or in 36 pairs per day. To understand this problem, experimental studies are undertaken to identify various factors such as injector temperature, mould temperature; that affects the production of waste. The work presented in this paper comprises a review of the relevant literature on the Six Sigma DMAIC improvement process, quality control tools, and the design of the experiments. After the experimentation following the Six Sigma process, the results showed that the defect occurred in approximately 0.5 per cent of the products or in 12 pairs per day; this decreased the production cost from 6,120 AUD per month to 2,040 AUD per month. This research aimed to reduce the amount of waste in men’s flat outsoles. Hence, the outcome of research presented in this paper should be used as a guide for applying the appropriate process for each type of outsole.

Assessment of robustness on analysis using headspace solid-phase microextraction and comprehensive two-dimensional gas chromatography through experimental designs

Plackett–Burman experimental design was applied for the robustness assessment of GC×GC–qMS (Comprehensive Two-Dimensional Gas Chromatography with Fast Quadrupolar Mass Spectrometric Detection) in quantitative and qualitative analysis of volatiles compounds from chocolate samples isolated by headspace solid-phase microextraction (HS-SPME). The influence of small changes around the nominal level of six factors deemed as important on peak areas (carrier gas flow rate, modulation period, temperature of ionic source, MS photomultiplier power, injector temperature and interface temperature) and of four factors considered as potentially influential on spectral quality (minimum and maximum limits of the scanned mass ranges, ions source temperature and photomultiplier power). The analytes selected for the study were 2,3,5-trimethylpyrazine, 2-octanone, octanal, 2-pentyl-furan, 2,3,5,6-tetramethylpyrazine, and 2-nonanone e nonanal. The factors pointed out as important on the robustness of the system were photomultiplier power for quantitative analysis and lower limit of mass scanning range for qualitative analysis.