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PubMed2000

Biotransformation of geraniol, nerol and citral by sporulated surface cultures of Aspergillus niger and Penicillium sp.

The biotransformation of geraniol, nerol and citral by Aspergillus niger was studied. A comparison was made between submerged liquid, sporulated surface cultures and spore suspensions. This bioconversion was also carried out with surface cultures of Penicillium sp. The main bioconversion products obtained from geraniol and nerol by liquid cultures of A. niger were linalool and alpha-terpineol. Linalool, alpha-terpineol and limonene were the main products obtained from nerol and citral by sporulated surface cultures, whereas geraniol was converted predominantly to linalool, also resulting in higher yields. Bioconversion of nerol with Penicillium chrysogenum yielded mainly alpha-terpineol and some unidentified compounds. With P. rugulosum the major bioconversion product from nerol and citral was linalool. The bioconversion of nerol to alpha-terpineol and linalool by spore suspensions of A. niger was also investigated. Finally the biotransformation with sporulated surface cultures was also monitored by solid phase microextraction (SPME). It was found that SPME is a very fast and efficient screening technique for biotransformation experiments.

Acyclic Monoterpenes↗

PubMed2002

Determination of chlorinated pesticides in water by SPME/GC.

Solid-phase microextraction (SPME) followed by gas chromatography (GC) coupled with an electron capture detector has been applied for the analysis of chlorinated pesticides in water. Molecule adsorption on 100 microm polydimethylsiloxane (PDMS) fibers was activated by immersion of the whole fiber-sample system in an ultrasonic bath. The good reproducibility, low detection limits and wide linear ranges obtained encourage the use of this technique in water control.

Adsorption↗

PubMed2003

Effect of residual chlorine on the analysis of geosmin, 2-MIB and MTBE in drinking water using the SPME technique.

The effect of chlorine on the analysis of three organic compounds (geosmin, 2-methylisoborneol (2-MIB) and methyl tert-butyl ether (MTBE)) in drinking water is elucidated. Three fibers for solid-phase microextraction (SPME) were employed for the extraction of the organic compounds from drinking water samples with and without free residual chlorine present. A gas chromatograph coupled with a mass spectrometer was used to analyze the compounds trapped by the fibers. The presence of chlorine substantially reduces the observed geosmin, 2-MIB, and MTBE concentrations. Depending on the analyte and chlorine concentrations, an experimental error of 10-70% may be observed due to the presence of free residual chlorine. The impact is larger for lower organic compound concentrations, and under higher residual chlorine conditions. To counteract the effect from residual chlorine, sodium thiosulfate was used to dechlorinate the water. After dechlorination the experimental error was less than 10%, suggesting that dechlorination is necessary when applying SPME for the extraction of organic compounds from chlorinated drinking water.

Camphanes↗

PubMed2003

Analysis of trihalomethanes in drinking water using headspace-SPME technique with gas chromatography.

In many drinking water treatment plants, the chlorination process is one of the main techniques used for the disinfection of water. This disinfecting treatment leads to the formation of trihalomethanes (THMs) such as chloroform, dichlorobromomethane, chlorodibromomethane and bromoform. In this study, headspace-solid-phase microextraction (HS-SPME, 85 microm carboxen/polydimethylsiloxane fiber) technique was applied for the analysis of THMs in drinking water. The effects of experimental parameters such as kinds of SPME fiber, the volume ratio of sample to headspace, the addition of salts, magnetic stirring, extraction temperature, extraction time and desorption time on the analysis were investigated. Analytical parameters such as linearity, repeatability and limit of detection were also evaluated. The results of THMs from the survey of Seongnam (Korea) drinking water samples showed that the highest total trihalomethane and chloroform were 24.03 and 13.34 microg/l, which were well within the Korean drinking water quality standard of 100 and 80 microg/l, respectively.

Chemistry Techniques, Analytical↗

PubMed2003

An unusual and persistent contamination of drinking water by cutting oil.

Drinking water contamination by materials, such as cutting oil, used to set up pipelines is an uncommon but possible event. This paper describes the analytical procedures used to identify the components of that contaminant in drinking water. Volatile and semi-volatile chemical species, responsible for an unpleasant taste and odour, were recognised by solid phase microextraction and GC/MS techniques. Among the volatile compounds, the presence of xylenes, bornyl acetate and diphenyl ether was confirmed by certificate standards and quantified in the most contaminated samples.

Environmental Monitoring↗

PubMed2001

Investigations on the sorption of phenols to dissolved organic matter by a QSAR study.

The sorption of various phenols to Aldrich-HA and BSA was investigated by solid phase microextraction (SPME). The Aldrich-HA sorption with log K(DOC)-values between 2 and 3 was determined, whereas the sorption to BSA with log K(DOC)-values between 2 and 6 was much stronger. To enable an estimation of sorption constants a QSAR model was investigated. The linear free energy relationship (LFER) model showed a good correlation between the sorption constants and the log K(OW)-values with correlation coefficients of R = 0.910 and R = 0.878 for Aldrich-HA and BSA, respectively.

Absorption↗

PubMed2002

On-fibre photodegradation studies of polychlorinated biphenyls using SPME-GC-MS-MS: a new approach.

The known advantages of solid-phase microextraction as a simple, one-step, rapid and solvent free extraction technique are exploited to study the photodegradation kinetics of polychlorinated biphenyls "on-fibre". The obtained results show the possibilities of this new approach not only to monitor the photolysis pathways of such compounds but to determine the photoproducts produced at different irradiation times and/or wavelengths. Photoproducts of PCB decomposition were less chlorinated biphenyls, among them some coplanar congeners have been found, which is important from a toxicological point of view.

Environmental Pollutants↗

PubMed2002

Temperature dependence of Henry's law constant in an extended temperature range.

The Henry's law constants H for chloroform, 1,1-dichloroethane, 1,2-dichloropropane, trichloroethene, chlorobenzene, benzene and toluene were determined by the EPICS-SPME technique (equilibrium partitioning in closed systems--solid phase microextraction) in the temperature range 275-343 K. The curvature observed in the ln H vs. 1/T plot was due to the temperature dependence of the change in enthalpy delta H0 during the transfer of 1 mol solute from the aqueous solution to the gas phase. The nonlinearity of the plot was explained by means of a thermodynamic model which involves the temperature dependence of delta H0 of the compounds and the thermal expansion of water in the three-parameter equation ln (H rho TT) = A2/T + BTB + C2, where rho T is the density of water at temperature T, TB = ln(T/298) + (298-T)/T, A2 = -delta H298(0)/R, delta H298(0) is the delta H0 value at 298 K, B = delta Cp0/R, and C2 is a constant. delta Cp0 is the molar heat capacity change in volatilization from the aqueous solution. A statistical comparison of the two models demonstrates the superiority of the three-parameter equation over the two-parameter one ln H vs. 1/T). The new, three-parameter equation allows a more accurate description of the temperature dependence of H, and of the solubility of volatile organic compounds in water at higher temperatures.

Organic Chemicals↗

PubMed2003

Characterisation of odorants emissions from landfills by SPME and GC/MS.

Odorous compounds from a landfill have been characterised by gas-chromatography-mass-spectrometry, identifying about 100 volatile organic compounds. Air samples from different landfill sites and from the environment have been analysed after a solid-phase microextraction on a three-phase fiber, DVB/Carboxen/PDMS, which allowed a preconcentration and the chromatographic data obtained from the most significant emission sources have been submitted to chemometric analysis in order to better establish specific markers of olfactory pollution. For example limonene was a typical tracer of fresh wastes, while p-cymene was characteristic of leachate and biogas. By the developed analytical procedure it has been evaluated the efficiency of a scrubber plant utilised in the landfill in order to remove malodour compounds. The average removal efficiency was not very high (about 23.5%) due to scarce ability in removing low polarity compounds. Furthermore, it has been demonstrated the suitability of a microgas chromatograph for the continuous on-site monitoring of air pollution in order to rapidly individuate emission sources of olfactive nuisances.

Air Pollutants↗

PubMed2003

Assessment of tin and butyltin species in estuarine superficial sediments from Gipuzkoa, Spain.

Ten superficial sediments from river estuaries of Gipuzkoa (North Spain) were collected and analyzed for nine metals (including tin, Sn) and butyltin compounds (monobutyltin, MBT; dibutyltin, DBT; tributyltin, TBT). Total metal concentration in the fine fraction (<63 micrometer) of the sediment was determined in aqua regia--hydrofluoric acid extracts by atomic absorption spectrometry. The butyltin species (BTs) were firstly extracted from the sediments with hydrochloric acid-methanol mixture. After derivatization with sodium tetraethyl borate, the organotin compounds were extracted by solid phase microextraction (SPME) in headspace mode. A fiber coated with 100 micrometer poly(dimethylsiloxane) was used for SPME. The organotin species were analyzed by gas chromatography-flame ionization detection. Analysis of the certified reference sediment (PACS-2) shown the suitability of the procedures for determination of metal contents and DBT-TBT species in contaminated sediments. Factorial analysis was used to examine the main sources of metals. Three factors represented more than 89% of the total variance of the metal system, and the Sn was related with Cu-Zn-Pb suggesting the same pollution source. The BTs concentrations in the area were high (TBT ranged from 0.05 to 5.48 mg Sn kg(-1)). The percentage of total butyltin species ( summation operator BTs) respect to the total Sn amount was higher than 4% in all the sediments, showing in the Bidasoa river estuary a remarkable value higher than 20%. Hence, the studied estuarine sediments reflect a pollution that is related with historical industrial and fishing activities of the area.

Environmental Monitoring↗

PubMed2003

Methods for sampling and analysis of tropospheric ethanol in gaseous and aqueous phases.

In this paper, we report on techniques for sampling and measuring ethanol in both the gas and aqueous phases of the lower troposphere. In the gas phase, the best sampling conditions were ensured by adsorption on Hayesep Q with a Chromosorb W AW coated with LiCl dryer (method 1) or by cryogenic trapping (method 2). An intercomparison campaign showed good agreement between both methods under various conditions. Method 1 (adsorption on Hayesep Q with dryer) is easier to set up and to carry away from the laboratory. Method 2 (cryogenic trapping) requires longer sampling time (up to 60 min while method 1 requires only 10-15 min). Method 1 is adapted to high concentrations of ethanol (>20 ppb) and low relative humidity (<30%). Method 2 gives more accurate results than method 1 for low ethanol concentrations (1-20 ppb). Comparing these results to previous studies, it is clear that sampling with appropriate solid adsorbents or with stainless steel canisters (with appropriate humidified air and short storage time) is adapted to urban or industrial environments where ethanol concentrations are high. Cryogenic sampling must be preferred for remote places where ethanol concentrations are low. Three techniques were tested for sampling ethanol in the liquid phase, namely solid phase microextraction, purge and trap injection, and direct injection. Among those, the latter was chosen for field measurements of ethanol in rain samples at an urban location. These first ever results at an urban location show concentrations ranging from <1 to 5 microM in rains, which agree with the expected range of concentrations. However, the purge and trap method showed detection limits that were 50 times lower and should be preferred for liquid phase ethanol measurements in rural and remote locations. Combining cryogenic trapping for the gas phase (method 2) and direct injection for the liquid phase is convenient and well adapted for a multiphase study of ethanol in the atmosphere, where simultaneous measurements in both phases are needed.

Adsorption↗

PubMed2002

Correlation of musty odor and 2-MIB in two drinking water treatment plants in South Taiwan.

Possible odor groups and intensity, and seasonal effects were elucidated in two representative water treatment plants (WTPs), Feng-Shen and Gun-Shi, in southern Taiwan. The flavor profile analysis (FPA) was employed to determine the odor groups for the source water, while a chemical analysis, solid-phase microextraction (SPME) coupled with a gas chromatograph and mass spectrometric detector (GC/MSD), was used to concentrate and subsequently analyze the corresponding water samples. FPA results show that fishy and musty odors were the two major odor groups in the source water. Results of chemical analysis showed that 2-methyl-isoborneol (2-MIB) was present in the source water. The correlation between 2-MIB concentration and the FPA intensity of musty odor was compared with the dose-response curve generated in the laboratory by the FPA panelists. The experimental data from the two water treatment plants follow the calibration curve closely, indicating that the musty odor of the two source waters were most likely contributed from 2-MIB. In addition, there is good correlation between logarithmic 2-MIB concentration and water temperature, substantiating the importance of seasonal effect. Although approximately 40-50% of 2-MIB removal was found in the treatment trains for the two WTPs, only an approximately 0.3 FPA intensity scale of reduction was expected.

Animals↗

PubMed2000

Determination of organic micropollutants in rain water for laboratory screening of air quality in urban environment.

Rain water may collect organic air pollutants, such as polycyclic aromatic hydrocarbons (PAHs), phthalate ester (PEs), pesticides, and polychrorinated biphenyls (PCBs), that could be present in air in consequence of different factors. The determination of these compounds in rain water samples consequently may be interesting for a first screening of air quality in urban and/or industrial areas. For this purpose, 3 areas of the city of Rieti (central Italy) were selected for rain water sampling: a) the city center, densely populated and with high road traffic; b) a suburban residential area; c) the industrial area, about 3 km out of the city center and along the state road. Wet-only precipitation collectors were used for sampling; solid-phase microextraction or liquid-liquid microextraction techniques followed by GC/MS determinations were applied for sample analysis. PCBs and pesticides were never found in the samples collected. On the contrary, some polycyclic aromatic hydrocarbons and phthalates were always found. Significant and seasonal differences in PAH levels were observed in the 3 different sampling areas, with higher values always found in the city center and during the winter period; on the contrary, PEs levels remained unchanged.

Air Pollutants↗

PubMed2003

Concentrations of nine alkenylbenzenes, coumarin, piperonal and pulegone in Indian bidi cigarette tobacco.

Indian-made bidi cigarettes sold in the United States are available in a variety of exotic (e.g. clove, mango) and candy-like (e.g. chocolate, raspberry) flavors. Because certain tobacco flavorings contain alkenylbenzenes and other toxic or carcinogenic chemicals, we measured the concentration of flavor-related compounds in bidi tobacco using a previously developed method. Twenty-three brands of bidis were sampled using automated headspace solid-phase microextraction and subsequently analyzed for 12 compounds by gas chromatography-mass spectrometry. Two alkenylbenzene compounds, trans-anethole and eugenol, were found in greater than 90% of the brands analyzed. Methyleugenol, pulegone and estragole were each detected in 30% or more of the brands, whereas safrole and elemicin were not detected in any of the brands. The flavor-related compounds with the highest tobacco concentrations were eugenol (12,000 microg/g tobacco) and trans-anethole (2200 microg/g tobacco). The highest eugenol and trans-anethole concentrations found in bidi tobacco were about 70,000 and 7500 times greater, respectively, than the highest levels previously found in US cigarette brands. Measurement of these compounds is crucial to evaluation of potential risks associated with inhaling highly concentrated flavor-related compounds from bidis or other tobacco products.

Allylbenzene Derivatives↗

PubMed2000

Separation methods for amino group-possessing pesticides in biological samples.

The separation methods for pesticides include liquid-liquid extraction, solid-phase extraction and solid-phase microextraction, gas chromatography (GC), GC-mass spectrometry (MS), GC-MS-MS, high-performance liquid chromatography (LC), LC-MS and LC-MS-MS. This review deals with each technique commonly used for extraction, chromatographic separation and detection of amino group possessing pesticides, such as diazines, triazines, carbamates, dinitroanilines and chloroacetanilides in biological samples. The methods presented for analysis of the pesticides in complicated biological matrices seem to be easily applicable to surface or groundwater in environmental chemistry.

Chromatography, Gas↗

PubMed1999

Matrix interferences in the analysis of benzene in urine.

The analysis of benzene in urine of the general population or of exposed workers can be performed with different methods using the 'purge and trap' or 'solid-phase microextraction' techniques in combination with gas chromatographic analysis and photoionisation or mass spectrometric detection. The published results, however, are deeply conflicting. Differences in sample preparation by different research groups and our own preliminary observations prompted us to investigate pre-analytical and analytical factors potentially capable of modifying the urinary benzene quantification results. Benzene concentrations were measured in 20 urine samples in relation to different conditioning conditions (at 24, 40 and 80 degrees C) and at basic or acid pH. Urinary protein concentrations were measured in the same samples. Urine heating at 80 degrees C yields benzene concentrations on average five times higher than at 24 degrees C. On acidification of urine, the benzene released increases up to 28-fold in comparison to that obtained at uncorrected 'physiological' pH. Despite a widely scattered data distribution, a statistically significant linear correlation was found between 'heat-released' and 'acid-labile' benzene values. There was no correlation between total urinary proteins present in 'physiological' concentrations (between 12 and 110 mg/l) and the different kinds of benzene in urine. Our results could perhaps be explained if it is supposed that part of the benzene in urine is absorbed onto sediment, or bound to specific proteins, or derived from parent molecules and is released with pH modification or heat administration. Our observations may also help to explain why the urinary benzene concentrations reported by different investigators vary considerably even when environmental levels are comparable.

Artifacts↗

PubMed2001

Synthesis of 4-methyl-5-arylpyrimidines and 4-arylpyrimidines: route specific markers for the Leuckardt preparation of amphetamine, 4-methoxyamphetamine, and 4-methylthioamphetamine.

General synthetic routes to 4-methyl-5-arylpyrimidines and 5-arylpyrimidines are described. 4-Benzylpyrimidine, 4-methyl-5-phenylpyrimidine, 4-(4-methoxybenzyl)pyrimidine, and 4-methyl-5-(4-methoxyphenyl)pyrimidine have been positively identified as route-specific by-products in the Leuckardt preparations of amphetamine and 4-methoxyamphetamine. Using headspace solid phase microextraction (SPME) 4-(4-methoxybenzyl)pyrimidine and 4-methyl-5-(4-methoxyphenyl)pyrimidine have been identified in illicit tablets containing 4-methoxyamphetamine. This is an indication that illicit laboratories use the Leuckardt method for the preparation of 4-methoxyamphetamine. Flatliner tablets containing 4-methylthioamphetamine have been screened for the presence of 4-(4-methylthiobenzyl)pyrimidine and 4-methyl-5-(4-methylthiophenyl)pyrimidine using both headspace and aqueous phase SPME. As these pyrimidines were not detected it would appear likely that illicit laboratories are not using the Leuckardt method for the preparation of 4-methylthioamphetamine.

Amphetamines↗

PubMed2003

Effect of hair care and hair cosmetics on the concentrations of fatty acid ethyl esters in hair as markers of chronically elevated alcohol consumption.

Fatty acid ethyl esters (FAEE) can be used as alcohol markers in hair. It was investigated in this study whether this diagnostic method is disturbed by hair care and hair cosmetics. Traces of ethyl myristate, ethyl palmitate, ethyl oleate and ethyl stearate were detected in all of 49 frequently applied hair care products by headspace solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS). The highest concentration was 0.003% in a hair wax. From experiments with separated hair samples of alcoholics as well as from the evaluation of the FAEE concentrations and the data about hair care of 75 volunteers (alcoholics, social drinkers and teetotalers) follows that usual shampooing, permanent wave, dyeing, bleaching or shading are of minor importance as compared to the drinking amount and other individual features. However, false positive results were found after daily treatment with a hair lotion containing 62.5% ethanol, with a deodorant and with a hair spray. As an explanation, it is assumed that FAEE are formed in the sebum glands also after regular topical application of products with a higher ethanol content.

Alcohol Drinking↗