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PubMed1980

Confirmation of low microgram/kg amounts of volatile N-nitrosamines in foods by low resolution mass spectrometry.

Volatile N-nitrosamines were confirmed in foods at concentrations of less than 10 micrograms/kg by full scan low resolution mass spectrometry. Ground samples were vacuum-distilled from mineral oil and condensed in liquid nitrogen-cooled vapor traps. The thawed distillate was extracted, the extract was cleaned up and concentrated, and the N-nitrosamine content was determined by combined gas chromatograph-thermal energy analysis. Positive samples were further cleaned up, trapped from a gas chromatographic column, and purged into a gas chromatograph-mass spectrometer for qualitative confirmation by full scan low resolution mass spectrometry. This procedure was applied to foods spiked at 1 microgram/kg and to fried commercial bacons with volatile N-nitrosamine contents of 2 to 5 micrograms/kg.

Animals↗
PubMed1993

[GC-MS analysis of influence of processing on volatile oil in Daphne genkwa Sieb. et Zucc].

The variation of volatile oils has been studied for GC-MS in different processed samples of Daphne genkwa. The results show that the contents of volatile oils in each processed sample are lower than these in the raw one, and the composition of those oils is greatly varied. The vinegar-fried and vinegar-boiled samples give more unknown ingredients.

Drugs, Chinese Herbal↗
PubMedDate not supplied

[Gas chromatographic method for determining esterase activity of proteolytic enzymes using continuous gas extraction of the volatile product].

A new procedure was developed for estimating the esterase activity of proteolytic enzymes by using CIS subcomponent of complement and N-alpha-benzoyl-L-arginine ethyl ester as a substrate. In contrast to other methods, which used static variants of gas chromatographic vapour-phase analysis for registration of the volatile reaction product alcohol, the procedure involved steady gas extraction of the volatile product in the gas stream over the incubation mixture. This method enabled to obtain a kinetic curve during one experiment as well as to elevate the accuracy of enzymatic activity estimation.

Arginine↗
PubMed1996

[Comparative research on the constituents of the volatile oil in the rhizome of Cibotium barometz (L.) J. Sm. and its processed products].

Volatile oil was extracted from the rhizome of Cibotium barometz for the first time. Its content was determined to be 83.3 micrograms/g, decreasing significantly after the drug was processed. Twelve constituents from the volatile oil were identified by method of GC-MS. The main constituents were organic acids. The contents of palmitic acid and linoleic acid were the highest. After Cibotium barometz was processed, some constituents were found decreasing and some increasing.

Drugs, Chinese Herbal↗
PubMed1999

Solid-phase microextraction gas chromatography/mass spectrometric analysis of volatile organic compounds in water

In this work, a solid-phase microextraction (SPME) method for the extraction of volatile organic compounds (VOCs) from water samples has been developed. Fifty-five volatile compounds (from the sixty listed in EPA method no. 524.2) were extracted from aqueous solutions using an SPME fiber coated with Carboxen-polydimethylsiloxane (Carboxen-PDMS), 75 &mgr;m film thickness. Time of sampling and chromatographic separation conditions were optimised. Standard solutions of VOC mixtures with concentrations as low as 0.05 ppb were analysed and their signal/noise ratios measured. Linearity of response for each component of the mixture was tested and mass spectral quality evaluated. A comparison with purge and trap analysis of VOCs was made. The method was applied to real-world samples of drinking, surface and leaching waters. Copyright 1999 John Wiley & Sons, Ltd.

Journal Article↗
PubMed1998

Characterization of aroma volatiles in tomatoes by sensory analyses.

Using gas chromatography-olfactometry and aroma extract dilution analysis 34 aroma compounds were found with flavour dilution factors > or = 4. (Z)-3-hexenal, hexanal, 1-octen-3-one, methional, 1-penten-3-one and 3-methylbutanal belonged to the most odour-active aroma volatiles in fresh tomatoes. Smell, taste and aftertaste of different tomato cultivars were evaluated by quantitative descriptive analysis. By applying principal component analysis to both sensory attributes and chemical compounds (odour-active aroma volatiles, titratable acid and reducing sugars) the first three components explained 70% of the total variance. The data set was reduced to the sensory attributes intensive, tomato, sour, fruity, sweet and bitter as well as to important chemical compounds. Relations between chemical compounds and sensory attributes were found.

Chromatography, Gas↗
PubMed1981

Nitrite-induced volatile mutagens from normal human feces.

Volatile mutagens (putative carcinogens) were produced from normal human and animal feces upon incubation with sodium nitrite in saline at 37 C for 48 hours. The mutagens were detected by using Ames' Salmonella typhimurium tester strain TA1535 without microsomes, on plates inverted over samples in sealed containers. Mutagenicity was maximal at 0.2 to 0.6 M NaNO2 and at pH 6.2 to 6.8. Reversions per plate varied from approximately 30 to 450 (1.5 to 25 x background) within the normal human population. Sodium ascorbate and alpha-Tocopherol (at one-half [NaNO2]) each reduced the mutagenicity by approximately 30%. Two standard N-nitroso-compounds were mutagenic in the system. We propose that the mutagenicity in our system is probably caused by the formation of volatile N-nitroso-compounds and that addition of nitrite to human feces in vitro enhances a process that occurs in vivo.

Ascorbic Acid↗
PubMed1982

Nitrite-induced volatile fecal mutagens: some preliminary studies.

Further studies are reported on the formation of volatile mutagens from normal human feces incubated with sodium nitrite at 37 degrees C. Volatile mutagens were detected using Ames' Salmonella typhimurium tester strain TA1535 on petrie plates inverted over samples in sealed containers. An optimal exposure period was shown to be approximately 24 hours. When plates inverted over samples were replaced periodically, mutagenicity during serial 24 hour or 48 hour periods could be measured. Mutagenicity was optimal during the second 24 hour period and the first 48 hour period with 0.6 M sodium nitrite, and in the first 24- and 48-hour period with 0.2 M sodium nitrite. Subsequent exposure periods showed decreasing mutagenicity with time. Because of the great differences in reactivity with nitrite in stools of healthy volunteers, the effect of mixing "high reacting" samples with "low reacting" samples were investigated. When "low reacting" samples were mixed with "high reacting" samples, a lower mutagenicity of the mixture was observed compared to a predicted "average" value. Autoclaving stool samples made very little difference in nitrite-induced mutagenicity and behavior in mixing experiments. Thus, fecal mutagens arise as a spontaneous chemical process involving nitrite ions and both dietary and flora factors may be important in their production or absence.

Adult↗
PubMed1986

Massive hemolysis following inhalation of volatile nitrites.

Volatile nitrites are drugs which have become widely used for their mood-altering and aphrodisiac effects. Their use has been associated with methemoglobinemia and mild hemolysis; more significant hemolysis has been noted in a patient with G6PD deficiency. We report here a case of massive hemolysis following inhalation of volatile nitrites in the absence of an apparent intrinsic red cell defect. It is important that health care workers are aware of side effects from these commonly abused substances.

Adult↗
PubMed1995

Estimation of risk of developing bladder cancer among workers exposed to coal tar pitch volatiles in the primary aluminum industry.

To confirm the relationship between exposure to coal tar pitch volatiles and bladder cancer among primary aluminum production workers, we carried out a case-control study among blue-collar workers who had worked more than 1 year between 1950-1979 in a major plant using mostly the Soderberg process in the Province of Québec. Cases of bladder cancer (ICD code 188) diagnosed between 1970-1979 (n = 69) were mostly included in a previously reported study. To these were added cases diagnosed between 1980-1988 (n = 69). Each case was matched to three controls on date of birth, date of hiring, and length of service at the company. Smoking habits were assessed from the medical records at the company. Benzene-soluble matter (BSM) and benzo(a)pyrene (BaP) were used as indicators of environmental exposure to coal tar pitch volatiles in the workplace. The estimated risk for current smokers was 2.63 (95% C.I. 1.29-5.37). Estimates of risk by occupational exposure were adjusted for smoking. Men who had worked in the Soderberg potrooms were at higher risk of developing the disease, the risk increasing with the time spent in these departments. Similarly, a strong association between risk and cumulative exposure to BSM or to BaP was observed. The risks associated with cumulative exposure to BSM (mg/m3-years) and to BaP (microgram/m3-years) were described with mathematical models. Using a linear model (1 + bx) and lagging 10 years before the diagnosis, BaP cumulative exposure was a better indicator of risk than BSM cumulative exposure. The risk for each year of exposure to BaP at a concentration of 1 microgram/m3 increased by 1.7% (0.8%-3.2%). Using the same model for BSM, a worker exposed to the current threshold limit value of 0.2 mg/m3 for 40 years will sustain a risk of 2.22 (1.56-3.48). Comparison of risks according to different periods of diagnosis (1970-1979 vs. 1980-1988) did not reveal any significant temporal changes on risk estimates.

Air Pollutants, Occupational↗
PubMed1987

Cytogenetic study in children chronically habituated to inhalation of volatile substances.

Deliberate inhalation of volatile substances is a common and harmful phenomenon among young persons around the world. Clinical and cytogenetic studies were performed in 35 children (33 boys and 2 girls) chronically habituated to inhalation of volatile agents, with the aim to define whether this practice is associated with chromosome abnormalities and if so to what extent. A significant increase in the rate of chromosome abnormalities and in the frequency of sister chromatid exchanges (SCE) was found in sniffers over the values in controls (p less than 0.001). Clinical, socioeconomic, and cytogenetic findings are discussed.

Adolescent↗
PubMed2006

Volatile components of lemur scent secretions vary throughout the year.

Olfactory signals can communicate a wide variety of information and are very important in many mammalian species. However, little is known about the olfactory communication of primates. This study used gas chromatography to examine the volatile components of the anogenital gland secretions of wild Milne-Edward's sifaka, Propithecus edwardsi (Primates, Indriidae) (n = 17), captured in Ranomafana National Park, Madagascar. We compared scent swabs of animals and examined differences between social group, age class, sex, and season. The only identified differences in the volatiles were between swabs from the different seasons; all other categories were statistically indistinguishable.

Age Factors↗
PubMed1987

Thermal desorption/gas chromatographic/mass spectrometric analysis of volatile organic compounds in the offices of smokers and nonsmokers.

The indoor air quality of the offices of smokers and nonsmokers was surveyed for volatile organic compound identities and concentrations. These results were examined to determine whether environmental tobacco smoke contamination could be distinguished from airborne pollutants outgassing from other sources. It was not possible to positively attribute volatile organic contaminants to environmental tobacco smoke. It was possible to distinguish between smokers' and nonsmokers' offices by determining airborne nicotine levels.

Air↗
PubMed1991

Volatile compounds detected in blood of drunk drivers by headspace/capillary gas chromatography/ion trap mass spectrometry.

As shown by others, ethanol and methanol appear in the breath of normals, and endogenous methanol becomes detectable also in the blood after intake of ethanol. In this study I have investigated whether low-molecular-weight volatile organics, other than methanol, arise in the blood of drunk drivers who had imbibed alcoholic beverages. To this end a method for searching for such compounds in the blood is described. It was based on headspace extraction, gas chromatographic separation on a DB-WAX capillary, and ion trap detection in the mass range 29-99 u. Detection limits, as defined by the analyte concentration that gives a signal equal to three times the standard deviation of the baseline noise, were estimated for the different mass numbers used in the substance search. Given the detection limits, presented as mmoles per litre (numbers within parentheses), in every drunk driver's blood with more than 10 mmol l-1 of ethanol between seven and nine different volatile substances were spotted. These were ethanol (0.15), 2-propanone (0.015), ethyl acetate (0.0005), 2-butanone (0.006), methanol (1.5), 2-propanol (0.06), ethanol (0.7), 2-butanol (0.03), and 1-propanol (0.03).

1-Propanol↗
PubMed1983

Evaluation of an exposure system using cells grown on collagen gels for detecting highly volatile mutagens in the CHO/HGPRT mutation assay.

Chinese hamster ovary (CHO) cells were grown on hydrated collagen gels, the overlaying medium removed leaving the cells at an air/collagen interface, and the cells exposed to a dynamic flow of ethylene oxide. Increases in CHO cell mutant frequency and decreases in cell viability were observed. To establish if the exposure system could be simplified, cells were exposed in sealed bottles (static system) to ethylene oxide. No substantial changes in cytotoxicity, mutant frequency, or effective concentration were noted when comparing static versus dynamic exposure systems. The general usefulness of the exposure system using cells grown on collagen gels was evaluated in a static system using propylene oxide and 1,2-dichloroethane, both of which were found to be mutagenic and cytotoxic. Comparatively, the exposure of cells by the collagen gel method was as effective in detecting genotoxic damage as were conventional methods (cells covered with medium) using cells grown on glass substrates. The exposure of CHO cells on collagen gels to highly volatile mutagens was simple and inexpensive, and may be generally useful in the detection of gaseous or volatile mutagens.

Animals↗
PubMedDate not supplied

An in vitro method for determination of tissue partition coefficients of non-volatile chemicals such as 2,3,7,8-tetrachlorodibenzo-p-dioxin and estradiol.

The development of an in vitro vial equilibration technique for determining tissue and liquid partition coefficients for non-volatile chemicals is described. Radiolabeled chemical dissolved in propylene carbonate is equilibrated with tissues or liquid at 37 degrees C in a vial system. The solvent must be essentially immiscible with the test material. The amount of chemical movement to the tissue or liquid is compared to an appropriate reference vial, and tissue or liquid:solvent partition coefficients are calculated. Tissue:solvent values divided by blood:solvent values provide tissue:blood partition coefficients required for developing physiologically based pharmacokinetic models for chemicals. These models are useful for estimating internal tissue doses to assess human risk from exposure to chemicals. Partition coefficients for various rat tissues, 0.9% saline solution and olive oil were determined in this study for radiolabeled 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and for the less fat-soluble compound, estradiol. The TCDD tissue:propylene carbonate partition coefficients were found to be: blood, 0.091; fat, 17.02; liver, 0.419; brain, 0.632; kidney, 0.305; muscle, 0.408. For estradiol, the tissue:propylene carbonate partition coefficients were: blood, 0.286; fat, 0.169; liver, 1.032; brain, 0.554. The TCDD results compared well with values reported and estimated from a more protracted in vivo approach. Thus, this current technique offers a simpler and time-saving alternative to in vivo approaches for determining the partition coefficients of non-volatile compounds.

Animals↗
PubMed2004

Dual column capillary gas chromatographic system for the in situ analysis of volatile organic compounds on a cometary nucleus.

Two Wall Coated Open Tubular capillary columns, coated with poly(cyanopropylphenyl-dimethyl)siloxane and poly(diphenyl-dimethyl)siloxane stationary phases, have been selected for use in the COmetary SAmpling and Composition space experiment for the separation and identification of the wide range of volatile organic compounds which could be present in cometary nuclei. This article presents the main characteristics of the tandem column system for the analysis of solutes of cometary interest within the constraints of space instrumental operating conditions. The high efficiency of the columns is demonstrated and the influence of the operating conditions on their separation properties are investigated. The studied columns exhibit complementary retention pattern: their use in a dual column system makes it possible to achieve the separation and the identification of the compounds of interest. Finally, the good analytical behavior of the columns when analyzing samples which include large amounts of water, the main presumed volatile in comets, is demonstrated. The presented results thus show the suitability of the selected tandem columns system for the desired analyses, and their performance on adaptation to in-situ cometary chemical investigation.

Chromatography, Gas↗
PubMed2006

Applicability of alkyl-bonded ultra-pure silica stationary phases for gradient reversed-phase HPLC of folates with conventional and volatile buffers under highly aqueous conditions.

Applicability of several alkyl-bonded silica stationary phases was tested for gradient RP-HPLC of folates under highly aqueous conditions. High retention of folates was achieved on alternative phases with enhanced polarity and classical phases with higher carbon content. Phases exhibiting polar secondary interactions were found to provide better selectivity for late-eluting folates, whereas selectivity for early-eluting folates was mostly dependent on hydrophobic interactions. Best selectivity in phosphate buffered mobile phase was achieved on polar-endcapped silica phases (Aquasil C18 and HyPurity Aquastar) followed by alternative Atlantis dC18. Classical phases exhibited poorer separation of 10-formyl-folic acid and 5-formyl-tetrahydrofolate, but it could be considerably improved by increasing the buffer pH. Strong secondary interactions of ion-exchange character on polar-embedded phases resulted in marked peak deterioration, loss of recovery and dramatic changes in retention behaviour for early- and late-eluting folates when changing the mobile phase composition and pH. Therefore, polar-embedded phases such as HyPurity Advance were found to be unsuitable for separating folates. Stationary phases exhibited peak deterioration when using volatile buffer of low ionic strength. Better results were obtained with classical phases, whereas alternative phases showed not only peak deterioration but also a decrease in recovery and poorer selectivity due to increased secondary interactions in volatile buffer.

Buffers↗