[Identification method of 2-methylisoborneol and geosmin in water by purge and trap-gas chromatography-mass spectrometry].

OBJECTIVE: To establishe an analysis and identification method for 2-methylisoborneol(2-MIB) and geosmin(GSM) in water using purge and trap-gas chromatography-mass spectrometry. METHODS: The samples were enriched and analyzed using a purge and trap system, followed by the separation on a DB-624(30 m×0.25 mm, 1.4 µm) chromatographic column. Quantification was performed using gas chromatography-mass spectrometry with the selected ion monitoring and internal standard calibration. RESULTS: The calibration curves for 2-MIB and GSM showed an excellent linearity in the range of 1 to 100 ng/L with R~2 values greater than 0.999. The detection limit and quantification limit for both 2-MIB and GSM were 0.33 ng/L and 1.0 ng/L, respectively. Spike recovery experiments were further carried on the source water and drinking water at three concentration levels. It showed that the average recoveries were from 82.0% to 111.0% for 2-MIB while 84.0% to 110% for GSM. Additionally, the test precision of 2-MIB and GSM ranged from 1.9% to 7.3% and 1.9% to 5.0%(n=6), respectively. The analysis of multiple samples including the local source water, treated water and distribution network water confirmed the existence of 2-MIB and GSM. CONCLUSION: Compared to the national standard(GB/T 5750.8-2023), the proposed method enables fully automated sample introduction and analysis without the extra pre-treatment. It provides the advantages of simplicity, good repeatability and high accuracy.

Dynamic changes of the main active constituents in valerian rhizome and root (Valeriana amurensis Smir. ex Kom.) during different harvest periods / Cambios dinámicos de los principales constituyentes activos del rizoma y raíz valeriana (Valeriana amurensis Smir. Ex Kom.) durante diferentes períodos de cosecha

Valeriana amurensis Smir. ex Kom. widely distributed in the northeast region of China and some region in Russia and Korea, and its underground parts (roots and rhizomes) being used to cure nervous system diseases such as insomnia. The active components including the essential oil and iridoids of underground parts were investigated in different harvest periods in order to evaluate the quality for the roots and rhizomes of V. amurensis. The content of the essential oil was obtained by hydrodistillation and bornyl acetate in the oil was quantitated by GC-EI. The iridoids, valepotriates were determined by potentiometric titration and the main component, valtrate was quantitated by HPLC-UV. The factors of biomass were considered in the determination of collection period. Statistical analysis of results showed that, the highest content of the essential oil per plant was 22.69 µl in withering period and then 21.58 µl in fruit ripening period, while the highest contents of bornyl acetate, valepotriates and valtrate per plant were 2.82 mg, 31.90 mg and 0.98 mg in fruit ripening period separately. Fruit ripening period was decided as the best harvest period for the content of active constituents and output of drug, and it would provide scientific basis for the artificial cultivation of V. amurensis.

Valeriana amurensis Smir. ex Kom. Se distribuye ampliamente en la región noreste de China y en algunas regiones de Rusia y Corea, y sus partes subterráneas (raíces y rizomas) se utilizan para curar enfermedades del sistema nervioso como el insomnio. Se investigaron los componentes activos, incluidos el aceite esencial y los iridoides de las partes subterráneas de V. amurensis en diferentes períodos de cosecha para evaluar la calidad de las raíces y rizomas. El contenido del aceite esencial se obtuvo mediante hidrodestilación y el acetato de bornilo en el aceite se cuantificó por GC-EI. Los iridoides, valepotriatos se determinaron mediante valoración potenciométrica y el componente principal, el valtrato se cuantificó por HPLC-UV. Los factores de biomasa fueron considerados en la determinación del período de recolección. El análisis estadístico de los resultados mostró que el mayor contenido de aceite esencial por planta fue de 22,69 µl en el período de marchitación y luego de 21,58 µl en el período de maduración de la fruta, mientras que el mayor contenido de acetato de bornilo, valepotriatos y valtrato por planta fue de 2.82 mg, 31.90 mg y 0,98 mg, respectivamente, en el período de maduración de la fruta por separado. Se definió el período de maduración de la fruta como el mejor período de cosecha para el contenido de constituyentes activos y la producción de droga, lo cual proporcionaría una base científica para el cultivo artificial de V. amurensis.

Investigation of borneols sold in Taiwan by chiral gas chromatography.

Borneol is a monoterpene that is widely used in traditional Chinese medicine. There are two different products sold in Taipei's traditional Chinese medicine market, natural and chemically synthesized borneol. Chemically synthesized borneol contains four stereoisomers, (+)-isoborneol, (-)-isoborneol, (-)-borneol, and (+)-borneol. The ratio of these four isomers in chemically synthesized and natural borneol products was determined by gas chromatography mass spectrometry. A huge variation between these products is highlighted in this survey. The results suggest that the Food and Drug Administrations in Asian countries should establish a regulatory standard regarding the ratio of the four different borneol isomers in both natural and chemically synthesized borneol.

Essential oil composition of aerial parts of Micromeria persica Boiss. from Western of Shiraz, Iran.

Micromeria persica Boiss. is medicinal and aromatic plant, belonging to the Lamiaceae family. The chemical composition of the essential oils (EOs) from aerial parts of M. persica were extracted using hydro-distillation method and analysed using GC and GC-MS. Fifty-two compounds were identified in the EOs of aerial parts of M. persica. The main chemical compositions were n-hexadecanoic acid (14.9%), thymol (9.5%), linoleic acid (8.0%), carvacrol (5.6%), (E)-nerolidol (5.5%), linolenic acid (5.5%), α-cadinol (2.7%), linalool (2.7%), borneol (2.6%), caryophyllene oxide (2.3%) and pulegone (2.0%). Presence of borneol, thymol, carvacrol and pulegone suggests the potential of this plant as a flavouring source in the food industry, being used in perfumery and cosmetics industry, vitamin E synthesis and exhibit strong fungicidal, antibacterial and antimicrobial activities.

Chemical composition and α-amylase inhibitory activity of the essential oil from Sabina chinensis cv. Kaizuca leaves.

Sabina chinensis cv. Kaizuca (SCK) is a variant of S. chinensis L. The essential oil from its leaves exhibited α-amylase inhibitory activity in vitro and the IC50 value was 187.08 ± 0.56 µg/mL. Nineteen compounds were identified from this essential oil by gas chromatography-mass spectrometry (GC-MS) analysis. The major compounds identified were bornyl acetate (42.6%), elemol (20.5%), ß-myrcene (13.7%) and ß-linalool (4.0%). In order to study the reason of the α-amylase inhibitory activity of this essential oil, the identified compounds were docked with α-amylase by molecular docking individually. Among these compounds, γ-eudesmol exhibited the lowest binding energy (-6.73 kcal/mol), followed by α-copaen-11-ol (-6.66 kcal/mol), cubedol (-6.39 kcal/mol) and α-acorenol (-6.12 kcal/mol). The results indicated that these compounds were the active ingredients responsible for the α-amylase inhibitory activity of essential oil from SCK.

Antinociceptive activity of the essential oil from Artemisia ludoviciana.

ETHNOPHARMACOLOGICAL RELEVANCE: Aerial parts of Artemisia ludoviciana are widely used in Mexico for treating gastrointestinal disorders, painful complaints and diabetes. AIM OF THE STUDY: To establish the preclinical efficacy as antinociceptive agent of the essential oil (EO) from the aerial parts of A. ludoviciana using well-known animal models. MATERIALS AND METHODS: Acute antinociceptive effect of EO (1, 10, 31.6, 100, and 316mg/kg, i.p.) was evaluated using the hot plate and paw formalin models in mice. The motor effects were assessed with the rota-rod and open field assays. The volatile components obtained by headspace solid phase microextraction (HS-SPME) and hydrodistillation were determined using gas chromatography coupled with mass spectrometry (GC-MS) analysis. RESULTS: EO decreased first and second phases of formalin test; in the first stage, the better effect was obtained with the treatment of 316mg/kg but in the second phase, time licking was attenuated at the doses of 31.6, 100 and 316mg/kg. The effectiveness of EO (ED50=25.9mg/kg) for attenuating neurogenic pain was corroborated using the hot plate test. The antinociceptive action of EO was blocked by naloxone suggesting that its mode of action involved an opioid mechanism. Furthermore, EO (316mg/kg) did not affect animal motor and coordination functions when tested by the rota-rod and open field tests. The latter results indicated that the pharmacological effects exerted by EO during the hot plate and formalin test are truly antinociceptive. GC-MS analysis of EO revealed that (±)-camphor, γ-terpineol, 1,8-cineole and borneol were the major volatile compounds of the plant. CONCLUSION: EO from A. ludoviciana showed significant antinociceptive effect, which appeared to be partially mediated by the opioid system. These findings could support the long-term use of A. ludoviciana for treating painful complaints in Mexican folk medicine.

Chemical composition and antioxidant activity of essential oil of six pinus taxa native to China.

The essential oils obtained by steam distillation from needles of six China endemic Pinus taxa (P. tabulaeformis, P. tabulaeformis f. shekanensis, P. tabulaeformis var. mukdensis, P. tabulaeformis var. umbraculifera, P. henryi and P. massoniana) were analysed by GC/MS. A total of 72 components were separated and identified by GC/MS from the six taxa. The major constituents of the essential oils were: α-pinene (6.78%-20.55%), bornyl acetale (3.32%-12.71%), ß-caryophellene (18.26%-26.31%), α-guaiene (1.23%-8.19%), and germacrene D (1.26%-9.93%). Moreover, the essential oils were evaluated for antioxidant potential by three assays (DPPH, FRAP and ABTS) and tested for their total phenolic content. The results showed that all essential oils exhibited acceptable antioxidant activities and these strongly suggest that these pine needles may serve as a potential source of natural antioxidants for food and medical purposes.

[Determination of 2-methylisoborneol and geosmin in drinking water using headspace solid phase micro-extraction coupled with gas chromatography-mass-spectrometry].

The odorous compounds of 2-methylisoborneol (2-MIB) and geosmin (GSM) heavily produced and released in water source are one of the most important factors leading to off-flavor emergencies and resident water consumption panic in drinking water. A headspace solid phase micro-extraction ( HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS) method was established for the simultaneous determination of these two trace earthy and musty compounds in reservoir water, reservoir soil and tap water. The conditions of HS-SPME, such as salt amount, extraction time and extraction temperature, were optimized based on orthogonal analysis. The qualitative and quantitative analyses of 2-MIB and GSM were carried out in the electron impact (EI) -selective ion scanning mode. The results showed that the linear relationship between peak area and concentration of 2-MIB and GSM was good enough (r2 0.998) from 5 to 1 000 ng/L, the limits of detection were 0.72 ng/L for 2-MIB, 0.34 ng/L for GSM and the limits of quantification were 2.40 ng/L for 2-MIB, 1.13 ng/L for GSM. When the target samples spiked in the range of 10-600 ng/L, the average recoveries of the target compounds were 93.6% - 107.7% ( RSD ≤ 6.1%, n = 6). Based on the above method, the target compounds in reservoir water, reservoir soil and tap water in a certain region of Liaoning Province were analyzed. The results showed that the two target odors in reservoir water were 3.0 -3.6 ng/L. As for the extract of the soil around the reservoir, 2-MIB was 8.1 ng/L and GSM was 17.8 ng/L. The odorous substances were not detected in the tap water. This method is simple, accurate, reliable, highly sensitive and no need of organic solvents. And it is suitable for the detection of 2-MIB and GSM in drinking water.

Determination of musty-odor compounds in water by gas chromatography-mass spectrometry with a needle-type sample-preparation device.

The musty-odor compounds (MOCs) 2-methylisoborneol (2-MIB) and geosmin in water samples were determined by a purge-and-trap method using a needle-type extraction device followed by gas chromatography-mass spectrometry. For the extraction of these compounds, a triple-layer-type extraction needle containing divinylbenzene and activated carbon particles as the particulate extraction media was introduced. Several experimental parameters, including the sample temperature during extraction, the addition of sodium chloride, and desorption conditions, were thoroughly optimized in this study. The detection limits for 2-MIB and geosmin were 1.0 and 0.5 ng L(-1), respectively. The method was successfully applied to the simultaneous determination of MOCs and other volatile organic compounds in tap-water samples.

Agents of earthy-musty taste and odor in water: evaluation of cytotoxicity, genotoxicity and toxicogenomics.

Considering the limited number of studies on the biological effects on human health of cyanobacterial compounds that cause taste and odor, the present study assessed the cytotoxic and genotoxic potentials of 2-methylisoborneol (2-MIB) and geosmin (GEO) using the MTT assay and the in vitro comet and cytokinesis-block micronucleus (CBMN-Cyt) assays in human HepG2 cells. The toxicogenomics of genes responsive to DNA damage and metabolization by the exposure of cells to 2-MIB and GEO were also investigated. The results showed that concentrations of 2-MIB and GEO above 100 and 75 µg/mL, respectively, were cytotoxic to HepG2 cells. Doses of 2-MIB (12.5, 25, 50, 75 and 100 µg/mL) and GEO (12.5, 25, 50, and 75 µg/mL) were unable to induce neither DNA damage nor events associated with chromosomal instability. Similarly, no concentration of each compound induced increments in the expression of CDKN1A, GADD45α, MDM2 and TP53 DNA damage responsive genes as well as in CYP1A1 and CYP1A2 metabolizing genes. Although cytotoxicity was observed, concentrations that caused it are much higher than those expected to occur in aquatic environments. Thus, environmentally relevant concentrations of both compounds are not expected to exhibit cytotoxicity or genotoxicity to humans.

Componentes volátiles de Eriope crassipes, Hyptis conferta, H. dilatata, H. brachiata, H. suaveolens y H. mutabilis (Lamiaceae) / Volatile compounds of analysis of Eriope crassipes, Hyptis conferta, H. dilatata, H. brachiata, H. suaveolens y H. mutabilis (Lamiaceae)

This work presents the analysis by GC-MS of volatile metabolites of six Lamiaceae from Arauca (Colombia). In stems and leaves of Eriope crassipes were determined as the most abundants: citronellic acid (53,8 percent and 66,2 percent), and methyl citronellate (15,7 percent and 14,5 percent). In the inflorescences of Hyptis conferta were identified: t-cadinol (49,4 percent), and caryophyllene oxide (13,0 percent). From leaves and flowers of Hyptis dilatata were found: delta-3-carene (11,0 percent and 0,5 por ciento), camphor (43,8 percent and 12,2 percent), bornyl acetate (3,2 percent and 25,5 percent), E-caryophyllene (12,8 percent and 22,3 percent), and palustrol (6,0 percent and 10,3 percent). In the leaves of Hyptis brachiata were recognized: E-caryophyllene (8,3 percent), alpha-humulene (19,8 percent), and germacrene D (13,0 percent). The principal compounds in leaves and flowers of Hyptis suaveolens were: alpha-phellandrene (9,4 percent and 0,4 percent), limonene (10,5 percent and 2,5 percent), 1,8-cineole (1,3 percent and 15,2 por ciento), fenchone (10,8 por ciento and tr), E-caryophyllene (26,3 por ciento and 8,0 por ciento), and germacrene D (6,7 por ciento and 14,0 por ciento). In the leaves of Hyptis mutabilis were determined: sabinene (6,6 percent) beta-elemene (6,8 percent), germacrene D (14,9 percent), beta-selinene (8,8 percent), alpha-selinene (9,1 percent), and bicyclogermacrene (6,1 percent), as the most abundants.

Este trabajo presenta el análisis por GC-MS de los metabolitos volátiles de seis Lamiaceae recolectadas en Arauca (Colombia). En tallos y hojas de Eriope crassipes se determinaron como mayoritarios: ácido citronélico (53,8 por ciento y 66,2 por ciento), y citronelato de metilo (15,7 por ciento y 14,5 por ciento). En las inflorescencias de Hyptis conferta se identificaron: t-cadinol (49,4 por ciento), y óxido de cariofileno (13,0 por ciento). En hojas y flores de Hyptis dilatata se encontraron: delta-3-careno (11,0 por ciento y 0,5 por ciento), alcanfor (43,8 por ciento y 12,2 por ciento), acetato de bornilo (3,2 por ciento y 25,5 por ciento), E-cariofileno (12,8 por ciento y 22,3 por ciento), y palustrol (6,0 por ciento y 10,3 por ciento). En las hojas de Hyptis brachiata se reconocieron: E-cariofileno (8,3 por ciento), alfa-humuleno (19,8 por ciento), y germacreno D (13,0 por ciento). Los compuestos principales en hojas y flores de Hyptis suaveolens fueron: alfa-felandreno (9,4 por ciento y 0,4 por ciento), limoneno (10,5 por ciento y 2,5 por ciento), 1,8-cineol (1,3 por ciento y 15,2 por ciento), fenchona (10,8 por ciento y tr), E-cariofileno (26,3 por ciento y 8,0 por ciento), y germacreno D (6,7 por ciento y 14,0 por ciento). En las hojas de Hyptis mutabilis se determinaron: sabineno (6,6 por ciento), beta-elemeno (6,8 por ciento), germacreno D (14,9 por ciento), beta-selineno (8,8 por ciento), alfa-selineno (9,1 por ciento), y biciclogermacreno (6,1 por ciento), como los más abundantes.

Determining indicator toxaphene congeners in soil using comprehensive two-dimensional gas chromatography-tandem mass spectrometry.

Toxaphene, which is a broad spectrum chlorinated pesticide, is a complex mixture of several hundred congeners, mainly polychlorinated bornanes. Quantifying toxaphene in environmental samples is difficult because of its complexity, and because each congener has a different response factor. Toxaphene chromatograms acquired using one-dimensional gas chromatography (1DGC) show that this technique cannot be used to separate all of the toxaphene congeners. We developed and validated a sensitive and quantitative method for determining three indicator toxaphene congeners in soil using an isotope dilution/comprehensive two-dimensional gas chromatography-tandem mass spectrometry (GC × GC-MS). The samples were extracted using accelerated solvent extraction, and then the extracts were purified using silica gel columns. (13)C10-labeled Parlar 26 and 50 were used as internal standards and (13)C10-labeled Parlar 62 was used as an injection standard. The sample extraction and purification treatments and the GC × GC-MS parameters were optimized. Subsequently the samples were determined by GC × GC-MS. The limits of detection for Parlar 26, 50, and 62 were 0.6 pg/g, 0.4 pg/g, and 1.0 pg/g (S/N=3), respectively, and the calibration curves had good linear correlations between 50 and 1000 µg/L (r(2)>0.99). Comprehensive two-dimensional GC gave substantial improvements over one-dimensional GC in the toxaphene analysis. We analyzed soil samples containing trace quantities of toxaphene to demonstrate that the developed method could be used to analyze toxaphene in environmental samples.

[Chemical composition of essential oil from Thymus citriodorus and its toxic effect on liver cancer cells].

OBJECTIVE: To analyze the chemical composition of essential oil from Thymus citriodorus and its toxic effect on liver cancer cells. METHODS: The essential oil from Thymus citriodorus leaves was extracted by steam distillation, and GC-MS was used for analyzing chemical composition. 35 components were identified which accounted for 95.44% of the total peak area. The main components were borneol (28.82%), thymol (14.43%), 3, 7-dimethyl-1, 6-octadiene-3-ol (8.26%), 1-methyl-4-[alpha-hydroxy-isopropyl] cyclohexene (8.23%) and terpenes camphor (5.1%), et. al. The toxic effects on HepG2 cells and expression of NF-kappabeta65 were measured by MTT assay and confocal laser scanning microscopy, respectively. RESULTS: The IC50 of HepG2 cells inhibition was 0.34%. The mean fluorescence intensity of NF-kappabeta65 expression was as follows: control group 323.25, 2(-10) concentration group 84.18, 2(-11) concentration group 197.93 and 2(-12) concentration group 261.43. CONCLUSION: The essential oil from Thymus citriodorus leaves has strong toxic effects. The induced apoptosis mechanism may be associated with the expression of NF-kappabeta65.

Determination of off-flavor compounds, 2-methylisoborneol and geosmin, in salmon fillets using stir bar sorptive extraction-thermal desorption coupled with gas chromatography-mass spectrometry.

A sensitive and solvent-less method for the determination of musty and earthy off-flavor compounds, 2-methylisoborneol (MIB) and geosmin (GSM), in salmon tissue was developed using stir bar sorptive extraction-thermal desorption coupled with gas chromatography-mass spectrometry (SBSE-TD-GCMS). MIB and GSM were solid phase extracted using polydimethylsiloxane (PDMS) coated stir bars, analyzed by gas chromatography, and detected in full scan mode of mass selective detector (MSD). Using this method, the calibration curves of MIB and GSM were linear in the range of 0.3-100ng/L, with a correlation coefficient above 0.999 and RSDs less than 4% (n=4). The limit of detection (LOD, S/N=3, n=6) and limit of quantification (LOQ, S/N=10, n=6) of MIB and GSM were both ∼0.3 and 1ng/L, respectively. The recoveries of MIB and GSM were 22% and 29% by spike in 30ng/L standard compounds, 23% and 30% by spike-in 100ng/L standard compounds in salmon tissue samples with good precision (<8% of RSDs, n=6), respectively. The recoveries of MIB and GSM were better than reported methodologies using SPME fibres (<10%) in fish tissue samples. This method was successfully applied to monitor and characterize depurated salmon fillet samples (0, 3, 6 and 10 days).

Toxicokinetic model assessment on the dechlorination of dietary toxaphene CHB-62 into CHB-44 in Atlantic salmon (Salmo salar L.).

European Union legislation on the upper limits of toxaphene in feed and food include the congeners CHB-26, CHB-62 and CHB-50 and is set at 50 µg kg⁻¹ feed for the sum of these three congeners. However, due to their elevated presence in fish, the congeners CHB-40 and CHB-41, CHB-44, and CHB-42 should also be included according to the European Food Safety Authority (EFSA) in 2005. Earlier trials with model zebra fish have shown in vivo dechlorination of dietary CHB-62 to CHB-44 and, to a lesser degree, of CHB-50 to CHB-40. Biomagnification patterns of Atlantic salmon, fed with technical toxaphene-enriched feeds, indicated that Atlantic salmon have a similar dechlorination. In the present study, a serial one-compartment physiological kinetic model, which includes differentiated growth of body components, is used to quantify the contribution of dechlorination to the congener-specific fillet accumulation of a mixture of dietary toxaphene congeners in Atlantic salmon. The model is assessed from experimental uptake and elimination kinetics of Atlantic salmon smolt fed with technical toxaphene for 122 days followed by a depuration period of 75 days in which the fish were fed toxaphene-free control feed. The serial one-compartment model shows that about 31% of CHB-44 that accumulated in the fillet originated from dietary CHB-62. In contrast, dechlorination of CHB-50 into CHB-40 is not significant. The results show that previously demonstrated in vivo dechlorination of CHB-62 into CHB-44 in zebra fish also occurs in the farmed fish species Atlantic salmon. This dechlorination can at least partly explain the relatively elevated CHB-44 observed in toxaphene fish surveys.

Detection and quantification of natural contaminants of wine by gas chromatography-differential ion mobility spectrometry (GC-DMS).

Rapid and direct, in situ headspace screening for odoriferous volatile organic compounds (VOCs) present in fresh grapes and in wines is a very promising method for quality control because the economic value of a wine is closely related to its aroma. Long used for the detection of VOCs in complex mixtures, miniature differential ion mobility spectrometry (DMS) seems therefore adequate for in situ trace detection of many kinds of VOCs of concern appearing in the headspace of selected foodstuffs. This work aims at a rapid detection, identification, and quantification of some natural and volatile contaminants of wine such as geosmin, 2-methylisoborneol (2-MIB), 1-octen-3-ol, 1-octen-3-one, and pyrazines (2-isopropyl-3-methoxypyrazine, IPMP, and 3-isobutyl-2-methoxypyrazine, IBMP). In the present study, these compounds were spiked at a known concentration in wine and analyzed with a hyphenated trap-GC-DMS device. The detection of all target compounds at concentrations below the human olfactory threshold was demonstrated.

UV-based advanced oxidation processes for the treatment of odour compounds: efficiency and by-product formation.

The occurrence of the taste and odour compounds geosmin and 2-methyl isoborneol (2-MIB) affects the organoleptic quality of raw waters from drinking water reservoirs worldwide. UV-based oxidation processes for the removal of these substances are an alternative to adsorption and biological processes, since they additionally provide disinfection of the raw water. We could show that the concentration of geosmin and 2-MIB could be reduced by VUV irradiation and the combination of UV irradiation with ozone and hydrogen peroxide in pure water and water from a drinking water reservoir. The figure of merit EE/O is an appropriate tool to compare the AOPs and showed that VUV and UV/O(3) yielded the lowest treatment costs for the odour compounds in pure and raw water, respectively. Additionally, VUV irradiation with addition of ozone, generated by the VUV lamp, was evaluated. The generation of ozone and the irradiation were performed in a single reactor system using the same low-pressure mercury lamp, thereby reducing the energy consumption of the treatment process. The formation of the undesired by-products nitrite and bromate was investigated. The combination of VUV irradiation with ozone produced by a VUV lamp avoided the formation of relevant concentrations of the by-products. The internal generation of ozone is capable to produce ozone concentrations sufficient to reduce EE/O below 1 kWh m(-3) and without the risk of the formation of nitrite or bromate above the maximum contaminant level.

Chemical composition and insecticidal activity of the essential oil of Illicium pachyphyllum fruits against two grain storage insects.

The aim of this research was to determine chemical composition and insecticidal activity of the essential oil of Illicium pachyphyllum fruits against two grain storage insects, Sitophilus zeamais and Tribolium castaneum, and to isolate any insecticidal constituents from the essential oil. The essential oil of I. pachyphyllum fruits was obtained by hydrodistillation and analyzed by GC-MS. A total of 36 components of the essential oil were identified, with the principal compounds in the essential oil being trans-ρ-mentha-1(7),8-dien-2-ol (24.56%), D-limonene (9.79%), caryophyllene oxide (9.32%), and cis-carveol (5.26%) followed by ß-caryophyllene (4.63%) and bornyl acetate. Based on bioactivity-guided fractionation, the three active constituents were isolated and identified as trans-ρ-mentha-1(7),8-dien-2-ol, D-limonene and caryophyllene oxide. The essential oil of I. pachyphyllum fruits exhibited contact toxicity against S. zeamais and T. castaneum adults, with LD(50) values of 17.33 µg/adult and 28.94 µg/adult, respectively. trans-p-Mentha-1(7),8-dien-2-ol (LD(50) = 8.66 µg/adult and 13.66 µg/adult, respectively) exhibited stronger acute toxicity against S. zeamais and T. castaneum adults than either caryophyllene oxide (LD(50) = 34.09 µg/adult and 45.56 µg/adult) and D-limonene (LD(50) = 29.86 µg/adult and 20.14 µg/adult). The essential oil of I. pachyphyllum possessed fumigant toxicity against S. zeamais and T. castaneum adults with LC(50) values of 11.49 mg/L and 15.08 mg/L, respectively. trans-p-Mentha-1(7),8-dien-2-ol exhibited stronger fumigant toxicity against S. zeamais and T. castaneum adults, respectively, with LC(50) values of 6.01 mg/L and 8.14 mg/L, than caryophyllene oxide (LC(50) = 17.02 mg/L and 15.98 mg/L) and D-limonene (LC(50) = 33.71 mg/L and 21.24 mg/L). The results indicate that the essential oil of I. pachyphyllum fruits and its constituent compounds have potential for development into natural insecticides or fumigants for the control of insects in stored grains.

Microwave-assisted purge-and-trap extraction device coupled with gas chromatography and mass spectrometry for the determination of five predominant odors in sediment, fish tissues, and algal cells.

Off-flavors are among the most troublesome compounds in the environment worldwide. The lack of a viable theory for studying the sources, distribution, and effect of odors has necessitated the accurate measurement of odors from environmental compartments. A rapid and flexible microwave-assisted purge-and-trap extraction device for simultaneously determining five predominant odors, namely, dimethyltrisulfide, 2-methylisoborneol, geosmin, ß-cyclocitral and ß-ionone, from the primary sources and sinks is demonstrated. This instrument facilitates the extraction and concentration of odors from quite different matrices simultaneously. This device is a solvent-free automated system that does not require cleaning and is timesaving. The calibration curves of the five odor compounds showed good linearity in the range of 1-500 ng/L, with correlation coefficients above 0.999 (levels=7) and with residuals ranging from approximately 77% to 104%. The limits of detection (S/N=3) were below 0.15 ng/L in algae sample and 0.07 ng/g in sediment and fish tissue samples. The relative standard deviations were between 2.65% and 7.29% (n=6). Thus the proposed design is ready for rapid translation into a standard analytical tool and is useful for multiple applications in the analysis of off-flavors.

Simultaneous determination of eight common odors in natural water body using automatic purge and trap coupled to gas chromatography with mass spectrometry.

Production and fate of taste and odor (T&O) compounds in natural waters are a pressing environmental issue. Simultaneous determination of these complex compounds (covering a wide range of boiling points) has been difficult. A simple and sensitive method for the determination of eight malodors products of cyanobacterial blooms was developed using automatic purge and trap (P&T) coupled with gas chromatography-mass spectrometry (GC-MS). This extraction and concentration technique is solvent-free. Dimethylsulfide (DMS), dimethyltrisulfide (DMTS), 2-isopropyl-3-methoxypyrazine (IPMP), 2-isobutyl-3-methoxypyrazine (IBMP), 2-methylisoborneol (MIB), ß-cyclocitral, geosmin (GSM) and ß-ionone were separated within 15.3 min. P&T uses trap #07 and high-purity nitrogen purge gas. The calibration curves of the eight odors show good linearity in the range of 1-500 ng/L with a correlation coefficient above 0.999 (levels=8) and with residuals ranging from approximately 83% to 124%. The limits of detection (LOD) (S/N=3) are all below 1.5 ng/L that of GSM is even lower at 0.08 ng/L. The relative standard deviations (RSD) are between 3.38% and 8.59% (n=5) and recoveries of the analytes from water samples of a eutrophic lake are between 80.54% and 114.91%. This method could be widely employed for monitoring these eight odors in natural waters.