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PubMed2003

Possible interferences of mercury sulfur compounds with ethylated and methylated mercury species using HPLC-ICP-MS.

The HPLC-ICP-MS coupling technique is able to separate and detect methyl, ethyl and inorganic mercury isotopes specifically. An identification of ethyl mercury(+) is not possible when the widely used sodium tetraethylborate derivatisation method in combination with GC-AFS/AAS or ICP-MS techniques is performed because it contains ethyl groups.An unidentified compound with the same retention time as ethyl mercury was found in the HPLC chromatograms of industrial sewage samples and humic-rich soils of microcosm experiments after applying water vapour distillation. We also observed such unidentified peaks in samples of heavily contaminated sites in Eastern Germany, separated by HPLC fractionation only. In the experiments described, different mercury sulfur adducts were synthesised and tested for their retention times in the HPLC-ICP-MS system. It was found that the compound CH(3)-S-Hg(+) showed the same retention time as the ethyl mercury standard. It is therefore possible that ethyl mercury detected in chromatography by comparison of the retention time could also be due to an adduct of a sulfur compound and a mercury species. CH(3)-S-Hg(+ )should be tested in other chromatographic mercury speciation methods for this effect. This work can also be regarded as a contribution to the discussion of artificially occurring methyl mercury in sediments during sample preparation.

Journal Article↗
PubMed1959

Protection by sulfur compounds against the air pollutants ozone and nitrogen dioxide.

Two distinct but related pathways of protection against the lethal effects of ozone and nitrogen dioxide are shown by (i) simultaneous inhalation of compounds that furnish -SH or -SS-, or both, and (ii) by injection of thiourea derivatives several days prior to exposure to these oxidant gases. The mechanism of (i) is believed similar to that proposed for the action of radiation-protective compounds; that of (ii) involves the development of a tolerance initiated by the thiourea against the oxidants.

Administration, Inhalation↗
PubMed2006

Comparison of headspace and direct single-drop microextraction and headspace solid-phase microextraction for the measurement of volatile sulfur compounds in beer and beverage by gas chromatography with flame photometric detection.

Three approaches based on headspace single-drop microextraction (HS-SDME), direct single-drop microextraction (Direct-SDME), and headspace solid-phase microextraction (HS-SPME), have been compared for analyzing volatile sulphur compounds (VSCs) in beer and beverage. Procedures and performance of the three methods have been contrasted through the determination of extraction efficiencies, precision, linearity and limits of detection. The overall process of HS-SDME and HS-SPME was applied to GC-FPD determination of five VSCs in beer and beverage.

Beer↗
PubMed2001

Mechanisms by which garlic and allyl sulfur compounds suppress carcinogen bioactivation. Garlic and carcinogenesis.

Overall, a host of studies provides compelling evidence that garlic and its organic allyl sulfur components are effective inhibitors of the cancer process. These studies reveal that the benefits of garlic are not limited to a specific species, to a particular tissue, or to a specific carcinogen. Several mechanisms are likely to account for this protection. Notable among these is a depression in nitrosamine formation and a reduction in carcinogen bioactivation. The benefits provided by garlic must be viewed as part of the entire diet, since several dietary constituents can influence the degree of protection. More than one compound is responsible for the anticancer properties associated with garlic. Future research should focus on how genetic variability and daily environmental factors influence the anticancer benefits attributed to garlic and its allyl sulfur components.

Allyl Compounds↗
PubMed1998

Trace chromatographic analysis of dimethyl sulfoxide and related methylated sulfur compounds in natural waters.

Dimethyl sulfoxide (DMSO) occurs in the environment as a result of a number of biogenic and anthropogenic production and emission processes. It is an environmentally significant compound because of its use as a substrate by bacteria and its potential role in the biogeochemical cycle of dimethyl sulfide (DMS), a climatically active trace gas. In this paper, current methods for DMSO determination at nanomolar levels in natural waters, all involving gas chromatography, are reviewed. Direct injection and separation of aqueous DMSO offers a simple and fast application, but exhibits limited sensitivity due to limitation on injection volumes. So far, most authors have preferred DMSO reduction and subsequent analysis of the evolved DMS by purge-and-trap preconcentration and flame photometric detection. Several reducing agents have been used, though some require cumbersome procedures or are very sensitive to operational conditions. The common algal component dimethylsulfoniopropionate (DMSP) acts as an interference in some reduction methods and, therefore, either DMSP elimination prior to DMSO analysis or correction a posteriori is required. DMSO can be analyzed along with DMS, methanethiol, dimethyl disulfide and DMSP in the same water sample, either sequentially or separately, so that comprehensive speciation of methylated sulfur is obtained. Owing to the biological activity of DMSO, appropriate water sampling and handling procedures must be applied. Acidification and freezing appear to be suitable for aqueous DMSO storage, although immediate analysis in the field is always preferable. Future directions of DMSO determination in aquatic environments are suggested.

Chromatography↗
PubMed2006

Relationship between total salivary protein content and volatile sulfur compounds levels in malodor patients.

OBJECTIVE: The purpose of this study was to evaluate the relationship between total salivary protein and VSC levels. STUDY DESIGN: A patient group comprised 67 patients from the Fresh Breath Clinic of the Dental Hospital, Tokyo Medical and Dental University, with 18 healthy subjects as a control group. Gas chromatography was used to measure concentrations of VSCs in mouth air. After collecting resting saliva, flow rate, pH, and the amount of total protein in saliva were measured. Salivary protein patterns were analyzed by polyacrylamide gel electrophoresis (PAGE). RESULTS: In the patient group, the amounts of total salivary protein were significantly correlated with CH3SH levels measured by GC, CH3SH/H2S ratio, and organoleptic score. In addition, a significant correlation between flow rate of salivary protein and CH3SH/H2S ratio and the higher levels of salivary proteins from PAGE analyses were found. CONCLUSIONS: Total salivary protein was considered to be involved in the formation of oral malodor as one of the nutrient sources. The total salivary protein could be changed both quantitatively and qualitatively in subjects with malodor.

Adult↗
PubMed2002

Gas-phase analysis of trimethylamine, propionic and butyric acids, and sulfur compounds using solid-phase microextraction.

Complaints due to odors are an important problem for the wastewater, composting, and animal agriculture industries. Accurate, objective measurement techniques are needed to monitor emissions, to develop new waste handling procedures, and to reduce the production of these volatile gases. Solid-phase microextraction was investigated as a technique for the determination of representative odorous gases. A flow-through Teflon chamber was used to expose the fibers to certified gas standards. A 75-microm carboxen-poly(dimethylsiloxane) (Car-PDMS) coating was used for trimethylamine (TMA), carbon disulfide (CS2), dimethylsulfide (DMS), and dimethyl disulfide (DMDS), and an 85-microm polyacrylate coating was used for propionic acid (PA) and butyric acid (BA). Using a 1-h fiber exposure time and a flow rate through the chamber of 72 mL/min, method detection limits were 2.38, 0.074, 0.150, 0.063, 1.85, and 1.32 ppbv for TMA, DMS, CS2, DMDS, PA, and BA, respectively. Enhanced detector signal was observed for all analytes under flow conditions, as compared to static conditions, and the porous nature of the Car-PDMS coating appears to increase the time needed for analytes to reach equilibrium under flow conditions.

Adsorption↗
PubMed2004

Effect of aminoethylcysteine ketimine decarboxylated dimer, a natural sulfur compound present in human plasma, on tert-butyl hydroperoxide-induced oxidative stress in human monocytic U937 cells.

Aminoethylcysteine ketimine decarboxylated dimer (AECK-DD) is a natural sulphur compound present in human plasma and urine and in mammalian brain. Recently, it has been detected in many common dietary vegetables. The aim of the present study was to evaluate the ability of AECK-DD to affect cellular response of U937 human monocytic cells to tert-butyl hydroperoxide-induced oxidative stress. AECK-DD was incorporated into cells, as confirmed by GC-MS analyses, without any cytotoxic effect. A 24 h treatment with 50 and 250 microM AECK-DD resulted in the incorporation of 0.10 +/- 0.01 and 0.47 +/- 0.08ng AECK-DD x 10(6) cells, respectively. U937 cells pretreated with AECK-DD (in the range 4-100 microM) showed an increased resistance to tert-butyl hydroperoxide-induced necrotic death, as revealed by a higher percent of survival measured at all incubation times with respect to control cells. Moreover, the protective effect exhibited by AECK-DD is significantly stronger with respect to that obtained with other common antioxidants (N-acetyl cysteine and trolox) and comparable, although somewhat higher, to that of vitamin E. This effect seems to be due to the ability of AECK-DD to reduce glutathione depletion and to inhibit lipid peroxidation during tert-butyl hydroperoxide treatment. It can be concluded that AECK-DD protects cultured human monocytic cells against tert-butyl hydroperoxide-induced oxidative stress and subsequent cell death, likely through an antioxidant action inside the cell. Due to its presence in both human plasma and urine, AECK-DD may play a role in the modulation of oxidative processes in vivo.

Antioxidants↗
PubMed2003

Mass spectrometry of polyaromatic sulfur compounds in the presence of palladium(II).

Electrospray ionization mass spectrometry (ESI-MS) and tandem MS in an ion trap were used to explore the reduction of a PdCl(2) solution and the role of the metal in the formation of organosulfur radical cations. For tandem MS experiments, a 32 Da neutral loss (M - S), was observed for dibenzothiophene, thianthrene and benzonaphthothiophene, whereas both 32 and 33 Da neutral losses were observed for 2-methyldibenzothiophene and 4,6-dimethyldibenzothiophene. The effects of several variables on the formation of molecular ions or molecular fragments were studied to optimize radical cation formation, including the concentration ratio between PdCl(2) and sulfur and the collision energy. Electrochemical and chromatographic data were used to provide an explanation for the relative sensitivity observed for a mixture of polyaromatic sulfur heterocycles.

Cations↗
PubMed2004

[Analysis of composition and structure of sulfur compounds in residual oils by pyrolysis-gas chromatography].

Flash pyrolysis-gas chromatography has been used to investigate macromolecular sulphur in heavy oil. The influences of pyrolysis time and pyrolysis temperature have been studied and the analytical methods of pyrolysis were set up. Sulfur-containing products were identified by comparing with reference data and semi-quantified by a pulsed flame photometric detector (PFPD). The investigation conducted on Dagang, Gudao, Qianguo, Russia and mixed Russia-Daqing residual oils using pyrolysis-gas chromatography showed that the contents and composition of sulphur compounds demonstrated various characters in different pyrolysates of residual oils.

Chromatography, Gas↗
PubMed1995

[Allergy and professional exposure to sulfur compounds: questions posed].

We present here four cases of respiratory diseases which may be due to the exposition or to the handling of sulfur derivatives due to their professional activity. The responsibility of these compounds stands on the clinical history, biological cellular tests and for one of them on the evolution under a metabisulfite-free diet and a positive oral provocation test at 5 mg. The present economical crisis makes the patient-clinician relationship difficult, due to patients' wishing to hide their pathologies or their professional activities.

Adult↗