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PubMed2006

Application of HS-SPME in the determination of potentially toxic organic compounds emitted from resin-based dental materials.

Leaching of volatile substances from resin-based dental materials may have a potential impact on the biocompatibility as well as safety of these materials. Information from manufacturers on ingredients in the materials is very often incomplete. Patients and dentists may be in contact with components emitted from cured dental fillings or from substrates applied in their preparation. Therefore, determination of the components of these materials is necessary for better prevention from possible harmful effects caused by dental fillings. The aim of this work was the isolation and identification of organic compounds evolved from four commercial resin-modified glass-ionomer cements (resin-based dental materials applied in dentistry) by using an alternative method of volatile compounds analysis-HS-SPME (headspace-solid phase microextraction). Dental materials were heated in closed vial at various temperatures and volatile substances released into the headspace phase above the sample were isolated on a thin polymeric fibre placed in SPME syringe. Identification was performed by using the GC-MS (gas chromatography-mass spectrometry) technique. Almost 50 RMGIC (resin-modified glass-ionomer cement) components (monomers and additives) were identified. The main identified leachables were: iodobenzene (DPICls-diphenyliodonium chloride degradation product), camphorquinone (photo-initiator), tert-butyl-p-hydroxyanisole (inhibitor), 4-(dimethylamino)ethyl benzoate (co-initiator), ethylene glycol dimethacrylate (monomer).

Compomers↗

PubMed1997

Identification of cheese-associated fungi using selected ion monitoring of volatile terpenes.

The cheese-associated fungi Penicillium commune, P. roqueforti, P.solitum, P. discolor and Aspergillus versicolor have been investigated for production of volatile terpenes for chemical identification, when grown on yeast extract agar. Volatiles were collected by headspace solid-phase microextraction. Selected ion monitoring of four to seven of the most characteristic ions of mainly sesquiterpenes made it possible to identify the fungi to species level within 2 d. In a mixed culture of P. roqueforti and P. commune, inoculated in a ratio of 1000:1, volatiles from both fungi could be detected within 3 d, making identification possible.

Aspergillus↗

PubMed2002

Influence of octanoic acid addition to medium on some volatile compounds and PR-toxin biosynthesis by Penicillium roqueforti.

AIMS: The effect of wheat kernel medium supplementation with octanoic acid on the formation of PR toxin and some volatiles by Penicillium roqueforti was investigated. METHODS AND RESULTS: Octanoic acid was added to the medium once, prior to inoculation (4.55 mg g-1), or periodically (total 27.3 mg g-1) during the 10 day course of incubation. No octanoic acid was added to the reference sample. Levels of 2-heptanone, 2-heptanol and aristolochene, a volatile intermediate in PR toxin biosynthesis, were monitored using a solid phase microextraction (SPME) technique. The contents of PR toxin and ergosterol were determined after incubation. Aristolochene was observed in the reference sample, and 10.4 mg kg-1 of PR toxin was detected after 10 days. In cultures periodically supplemented with octanoic acid, no aristolochene or PR toxin were observed. However, in samples supplemented with octanoic acid only prior to incubation, the aristolochene level was 25% that in the reference sample, and PR toxin content was 3.4 mg kg-1. SIGNIFICANCE AND IMPACT OF THE STUDY: These data suggest that a high level of octanoic acid in the medium prevents PR toxin formation by P. roqueforti.

Caprylates↗

PubMed2001

Different stereoselectivity in the reduction of pulegone by Mentha species.

Aqueous solutions of [2H]-labeled pulegone enantiomers were fed to Mentha spicata ssp. spicata L. and Mentha spicata ssp. crispata L. shoot tip and first leaf pair. After solid phase microextraction the essential oil was analysed with enantioselective multidimensional gas chromatography/mass spectrometry. Both Mentha spicata species were able to convert labelled (1R)- and (1S)-pulegone at the same rate into the corresponding menthone and isomenthone, indicating an unspecific process. The reduction of both pulegone enantiomers preferably led to the cis-stereoisomers. The observed stereoselectivity is completely different from those of pulegone reduction by Mentha x piperita L.

Cyclohexane Monoterpenes↗

PubMed2000

Are variations in cuticular hydrocarbons of queens and workers a reliable signal of fertility in the ant Harpegnathos saltator?

One of the key features of insect societies is the division of labor in reproduction between one or a few fertile individuals and many sterile nestmates that function as helpers. The behavioral and physiological mechanisms regulating reproduction in ant societies are still not very well understood, especially in species in which all colony members are reproductively totipotent. In the ponerine ant Harpegnathos saltator, queen-worker dimorphism is very limited, and a few mated workers reproduce ("gamergates") once the founding queen becomes senescent. Worker oviposition is regulated by highly directed aggressive interactions among nestmates, who can recognize different levels of ovarian activity. We show that variations in cuticular hydrocarbons (CHC) correlate with oogenesis, both for queens and workers. 13,23-Dimethylheptatriacontane is present in egg-layers, but not in infertile workers and queens. Proportions of other CHCs vary as well, resulting in clear separation of the ants in a multivariate analysis. Egg-layers are characterized by an elongation of the chain length of CHCs. We used solid-phase microextraction to measure CHCs in live ants that were experimentally induced to start producing eggs. Over a period of 118 days, CHC profiles of infertile workers changed completely to that of reproductives. The effect of age can be excluded in this modification. This striking correlation of ovarian activity with CHC variation and its correspondence with the observed recognition behavior exhibited by the workers toward egg-laying nestmates suggests that CHCs serve as a fertility signal in the ant H. saltator, a reliable basis for regulating reproduction.

Animals↗

PubMed2001

Detection of microbial volatile organic compounds (MVOCs) produced by moulds on various materials.

Twelve fungal species were screened for microbial volatile organic compounds (MVOCs): Aspergillus fumigatus, A. versicolor, A. niger, A. ochraceus, Trichoderma harzianum, T. pseudokoningii, Penicillium brevicompactum, P. chrysogenum, P. claviforme, P. expansum, Fusarium solani and Mucor sp. More than 150 volatile substances derived from fungal cultures have been analysed by head-space solid-phase microextraction (HS-SPME). Each species had a defined MVOC profile which may be subjected to considerable modification in response to external factors such as cultivation on different substrata. The cultivation on different substrata changes the number and concentration of MVOCs. Species-specific volatiles may serve as marker compounds for the selective detection of fungal species in indoor environments. Examination of MVOCs from indoor air samples may become an important method in indoor air hygiene for the detection of type and intensity of masked contamination by moulds.

Air Pollution, Indoor↗

PubMed2005

Analysis of volatile compounds in some typical Brazilian fruits and juices by SPME-GC method.

This paper describes the analysis of volatile organic compounds (VOC) in typical Brazilian fruit and fruit juices by a solid-phase microextraction (SPME) method using a capillary gas chromatography system with flame ionization detection and mass spectrometry (GC-MS). A SPME holder with a 100-microm polydimethilsiloxane fibre coating was utilized. The optimal conditions were desorption at 220 degrees C for 1 min, absorption at 50 degrees C for 20 min and 4.00 ml of sample in the headspace vial. The method gave good precision and showed a linear response. More than 100 VOC were identified in the fruit and juices studied by GC-MS. The method was employed to quantify ethanol, naphthalene and benzoic acid in four different species of Brazilian fruit and their juices.

Anacardium↗

PubMed2006

Study of barrier properties and chemical resistance of recycled PET coated with amorphous carbon through a plasma enhanced chemical vapour deposition (PECVD) process.

Many studies have been carried out in order to make bottle-to-bottle recycling feasible. The problem is that residual contaminants in recycled plastic intended for food packaging could be a risk to public health. One option is to use a layer of virgin material, named functional barrier, which prevents the contaminants migration process. This paper shows the feasibility of using polyethylene terephthalate (PET) recycled for food packaging employing a functional barrier made from hydrogen amorphous carbon film deposited by Plasma Enhanced Chemical Vapour Deposition (PECVD) process. PET samples were deliberately contaminated with a series of surrogates using a FDA protocol. After that, PET samples were coated with approximately 600 and 1200 Angstrons thickness of amorphous carbon film. Then, the migration tests using as food simulants: water, 10% ethanol, 3% acetic acid, and isooctane were applied to the sample in order to check the chemical resistance of the new coated material. After the tests, the liquid extracts were analysed using a solid-phase microextraction device (SPME) coupled to GC-MS.

Carbon↗

PubMed1998

Determination of pesticide residues in wine by SPME and GC/MS for consumer risk assessment.

An analytical procedure applying solid phase microextraction (SPME) combined with gas chromatography/ mass spectrometry (GC/MS) for the detection of pesticide residues in wine was performed for the determination of 14 of the pesticides most frequently used on grapes (insecticides, fungicides, herbicides). As SPME combines the possibility of a single-step extraction with other advantages (short sampling times, solvent-free procedure, speedy extraction, low cost and simplicity) it could be successfully used either for screening or routine analysis for detecting pesticides of different chemical classes in wines, even at trace levels. The analytical procedure performed showed minimum detectable quantities ranging from 0.10 microgram/l to 6.0 micrograms/l and precision from 9.7% to 18% (as relative standard deviation of 1 microgram/l levels), assuring high sensitivity and precision of analysis. Twenty-one wine samples (10 white wines and 11 red wines) available on the Italian market were analysed with the procedure described and about 57% were positive for one or more pesticides. An approach for consumer risk assessment on the basis of the data obtained was proposed for further assessments of the daily dietary intake of pesticides through wine.

Calibration↗

PubMed2003

Volatile fatty acids as malodorous compounds in wool scouring water and lanolin. Origin and characterisation.

Volatile fatty acids (C2-C7) analysis in wool scouring water and lanolin is presented. These substances are of major interest as malodorous compounds in urban and industrial wastewaters. In this work, they have been analysed in wool scouring water by headspace solid-phase microextraction followed by gas chromatography negative chemical ionisation mass spectrometry. Most of the volatile fatty acids have been identified at microg g(-1) levels. In addition, since lanolin is a major impurity of raw wool, volatile fatty acid patterns of wool scouring water and lanolin have been compared in order to establish the origin of these compounds in the wastewater. Finally, the efficiency of the deodorization step, mandatory to obtain commercial lanolin, has been assessed taking into account the decrease in volatile fatty acid content from the raw wool to the lanolin.

Animals↗

PubMed2004

Occurrence and abatement of volatile sulfur compounds during biogas production.

Volatile sulfur compounds (VSCs) in biogas originating from a biogas production plant and from a municipal sewage water treatment plant were identified. Samples were taken at various stages of the biogas-producing process, including upgrading the gas to vehicle-fuel quality. Solid-phase microextraction was used for preconcentration of the VSCs, which were subsequently analyzed using gas chromatography in combination with mass spectrometry. Other volatile organic compounds present also were identified. The most commonly occurring VSCs in the biogas were hydrogen sulfide, carbonyl sulfide, methanethiol, dimethyl sulfide, and dimethyl disulfide, and hydrogen sulfide was not always the most abundant sulfur (S) compound. Besides VSCs, oxygenated organic compounds were commonly present (e.g., ketones, alcohols, and esters). The effect of adding iron chloride to the biogas reactor on the occurrence of VSCs also was investigated. It was found that additions of 500-g/m3 substrate gave an optimal removal of VSCs. Also, the use of a prefermentation step could reduce the amount of VSCs formed in the biogas process. Moreover, in the carbon dioxide scrubber used for upgrading the gas, VSCs were removed efficiently, leaving traces (ppbv levels). The scrubber also removed other organic compounds.

Air Pollutants↗

PubMed2005

Measuring the effect of photocatalytic purifiers on indoor air hydrocarbons and carbonyl pollutants.

Laboratory tests of photocatalytic air purifiers are usually performed with a single pollutant, in the parts per million by volume domain and at airflow rates < or =0.1 m3/hr. Clearly, it is necessary to probe photocatalytic materials and apparatuses under real conditions or conditions closely mimicking reality. Photocatalytic prototypes were placed in an ordinary room. To collect hydrocarbons over a shorter period (15 min) than with adsorbent-containing cartridges, solid-phase microextraction (SPME) was used. Typically, concentrations in substituted benzene hydrocarbons and tetrachloroethene were decreased to 20-35% of initial values; toluene and m- + p-xylene concentrations dropped to 2-6 parts per billion by volume, and o-xylene and benzene concentrations were still lower. In the absence of appropriate, commercialized SPME fibers, carbonyl compounds (both formed and destroyed by photocatalysis) were extracted using cartridges containing 2,4- dinitrophenylhydrazine-coated silica. The concentration ranges (in parts per billion by volume) were shifted to higher values in treated air: from 9-15.5 to 12.5-18 for methanal, from 1.5-3 to 8-11.5 for ethanal, and from 4.5-19 to 8-26.5 for propanone with the prototype used; these unprecedented results do not exclude using photocatalysis to treat air, but they illustrate that improvement is needed. Because these tests are time-consuming, preliminary tests are useful; results obtained with a 225-L closed-loop, airtight, photocatalytic reactor with an external turbine enabling the ambient air inside the reactor to be circulated through the purifier device at 15-450 m3/hr flow rates are reported.

Air Pollutants↗

PubMed2007

Comparison between urinary o-cresol and toluene as biomarkers of toluene exposure.

The characteristics of urinary o-cresol (o-C) and urinary toluene (TOL-U) as biomarkers of occupational exposure to toluene were comparatively evaluated. One hundred healthy male rotogravure printing workers and 161 male and female control subjects were studied. Personal exposure to airborne toluene (TOL-A) during the shift was determined as a time-weighted average. Simple analytical procedures based on solid phase microextraction followed by gas chromatography/mass spectometry analysis were applied to the determination of end-shift o-C and TOL-U. Median TOL-A was 48 (6.0-162.0) mg/m3 in printers and 0.021 (<0.003-0.137) mg/m3 in controls. o-C was 0.185 (0.032-0.948) mg/g creatinine in printers and 0.027 (<0.006-0.330) mg/g creatinine in the controls. TOL-U was 7.6 (1.8-23.9) microg/L in printers and 0.140 (0.094-0.593) microg/L in the controls. According to all indices, exposure to toluene was higher in printers than in the controls. Nevertheless, the distribution of o-C in the two groups partially overlapped, whereas such behavior was not found in TOL-U. Both o-C and TOL-U in printers were correlated with TOL-A (Pearson's on log10-transformed variables r = 0.704 and 0.844, respectively) and with each other (r = 0.683). Smoking habits significantly increased the excretion of o-C but not of TOL-U. From the point of view of sampling conditions and analytical requirements, TOL-U and o-C showed similar properties, but comparison of their intrinsic characteristics showed that TOL-U had higher specificity and sensitivity, lower background values, was better correlated with airborne exposure, and was not influenced by cigarette smoking. Therefore TOL-U may be considered superior to o-C as a biomarker of occupational exposure to toluene.

Adult↗

PubMed2005

Characterization of odors from limed biosolids treated with nitrate and anthraquinone.

Complaints from the public due to odor emissions are one of the biggest problems associated with any biosolids land application program. Chemical additives to reduce or mask odors are one option for producers; however, many chemicals are too expensive or are too unstable to use safely. This project provides a preliminary evaluation of nitrate or nitrate + anthraquinone as additives in controlling odors from limed biosolids. Over a twenty-four day period, odors were measured in the headspace over several treatment levels using two different chemical analysis tools along with olfactometric evaluation of odor intensity and hedonic tone. On six days during the sample period, hydrogen sulfide was measured using a Jerome 631X, a sensor that also responds to other reduce sulfur gases. Other specific sulfides, amines, and mercaptans were also determined using solid phase microextraction with gas chromatography-mass spectrometry. A simple sniff test approach was used with six panelists on five days during the project. The chemical analysis results revealed that the addition of nitrate and especially nitrate + anthraquinone was effective in reducing concentrations of hydrogen sulfide and methylmercaptan when compared to untreated limed biosolids. However, the olfactometric results did not reveal any significant differences between treatments. The panelists also found that all treatments exhibited a fishy or ammonical character, indicative of amines, or ammonia. More advance olfactometric analysis utilizing dilution techniques might have been able to distinguish between treatments, but it is likely that amines were the dominant odorant released from all treatments. This preliminary project suggests that chemical addition of nitrate or nitrate + anthraquinone would be most effective in controlling odors from unlimed biosolids such as anaerobically digested materials.

Anthraquinones↗

PubMed2005

Propylene glycol vapor contamination in controlled environment growth chambers: toxicity to corn and soybean plants.

A major, often unrecognized variable regulating plant growth in semi-closed environment is air contaminant. The vapor of propylene glycol (PG), which was used as coolant in growth chambers, has been found to be toxic to corn (Zea mays L.) and soybean (Glycine max L.) plants. PG solution leaked from a valve packing system and volatilized to vapor, which was trapped in a semi-closed growth chamber. Symptoms of leaf edge chlorosis, later developing into necrosis, were observed on the third day of emergence or on the third day after moving healthy plants into the chamber. For young soybean plants, symptoms were slightly different from those observed in corn plants; the chlorosis symptoms were not uniformly distributed on all leaves. Some soybean leaves curled up and others had white spots. This problem was identified by using a portable photoionization detector to obtain instantaneous readings of total volatile organic compound concentrations inside the chambers. The presence of PG in selected chambers was verified using sample collection with solid phase microextraction (SPME) followed by analysis with multi-dimensional gas chromatography mass spectrometry (MD-GC-MS). This information is pertinent to researchers who use controlled environment to grow plants.

Air Pollutants↗

PubMed2005

Optimization of a methodology for the determination of organochlorine pesticides in surface water by SPME-GC/MS.

In the present work experimental conditions were optimized for the analysis of organochlorine traces in water matrix using solid-phase microextraction (SPME) followed by gas chromatography with mass selective detector. The parameters including time of exposure of the fiber in the aqueous sample, fiber type, agitation speed, pH, ionic forces, temperature of adsorption, and time of desorption were evaluated. The best conditions to analyze organochlorine were obtained by using higher than room temperature, agitation of the sample, extraction time of 40 min, and polyacrylate fiber.

Adsorption↗

PubMedDate not supplied

Fatty Acid ethyl esters in scalp, pubic, axillary, beard and body hair as markers for alcohol misuse.

AIMS: This study examined the possibility of using hair samples other than scalp hair for analysis of fatty acid ethyl esters (FAEE) as markers for alcohol misuse. METHODS: Samples of scalp and pubic hair and, if available, axillary, beard and body hair of one teetotaller, five moderate social drinkers and 22 fatalities were analysed for FAEE by head-space solid-phase microextraction and gas chromatography-mass spectrometry. The sum of the concentrations of ethyl myristate, ethyl palmitate, ethyl oleate and ethyl stearate (C(FAEE)) in the hair samples was compared with information about the drinking behaviour of the individuals. RESULTS: Although there were large differences in the analyte concentrations in hair from different sites in the same individual, cases of chronic excessive alcohol consumption were characterized by C(FAEE) > 1.0 ng/mg in almost all samples. CONCLUSION: FAEE concentrations in hair other than scalp hair can be used as markers of chronic alcohol misuse.

Alcoholism↗

PubMedDate not supplied

Concentration of fatty acid ethyl esters in hair of alcoholics: comparison to other biological state markers and self reported-ethanol intake.

AIMS: In a variety of clinical and forensic situations long term use of alcohol must be monitored. In this project we explore the utility of fatty acid ethyl esters (FAEE) in this regard. Additionally, we propose a cut-off value of FAEE to distinguish teetotallers/moderate/social drinkers from alcoholics or individuals drinking at harmful levels. PATIENTS AND METHODS: FAEE levels from 18 alcohol-dependent patients in detoxification were contrasted with those of 10 social drinkers and 10 teetotallers. FAEE in hair were determined, using headspace solid phase microextraction and gas chromatography mass spectrometry. C(FAEE), as sum of the concentrations of four esters, was compared to a major FAEE, ethyl palmitate. PEth was measured in heparinized whole blood with a high pressure liquid chromatography (HPLC) method. Drinking validation criteria include self reports, phosphatidyl ethanol (PEth) in whole blood as well as the traditional markers of heavy drinking, gamma glutamyl transpeptidase (GGT), mean corpuscular volume (MCV) and carbohydrate deficient transferrin (CDT). RESULTS: Receiver-operating characteristic (ROC) curve analysis for C(FAEE), indicated a sensitivity of 100% and a specificity of 90% for a cut-off of 0.29 ng/mg. By using a cut-off of 0.4 ng/mg, C(FAEE) identified 94.4% correctly. C(FAEE) and ethyl palmitate were significantly associated (r = 0.945; P < 0.001) as were C(FAEE) and PEth (r = 0.527; P = 0.025). No significant correlation was found between C(FAEE) and total grams of ethanol consumed last month, blood-alcohol concentration at admission to the hospital, CDT, MCV, or GGT. Among the serum and blood markers, %CDT identified 47.1%, MCV 38.8% and GGT 72.2% of patients with chronic intake of higher amounts of ethanol correctly, whereas PEth achieved 100% accuracy. CONCLUSIONS: The data suggest that C(FAEE) is a potentially valuable marker of chronic intake of high quantities of ethanol. Furthermore, the results indicate that a reasonable and provisional FAEE cut-off to distinguish between social/moderate and heavy drinking/alcoholism in hair is 0.4 ng/mg.

Adult↗