Concentrations Of Carbon Disulfide Research Articles

Multiparameter gas sensor based on UV-SFR combined with wavelet transform-neural network at ppb level

Abnormal concentrations of nitric oxide (NO), ammonia (NH3), carbon disulfide (CS2) and sulphur dioxide (SO2) in exhaled breath are closely associated with diseases in specific organs of the body. Meanwhile, the above gases are also common pollutants in the atmosphere, and effective online detection of them plays a key role in disease prevention and environmental pollution prevention. This study reports a multiparameter gas sensor system based on the combination of ultraviolet segmented fitting reduction (UV-SFR) and wavelet transform-neural network (WT-NN) model for simultaneous online detection of the concentrations of NO, NH3, CS2 and SO2. Firstly, to avoid the occurrence of spectral baseline drift and absorption peak intensity reduction, a UV-SFR method is proposed for the discrete single peak type absorption spectra contained in the UV spectra. Our method can remove the slow change absorption induced by other factors, and ultimately obtain the differential absorption spectra of the gas mixtures. Then, the WT is used to denoise the differential absorption spectra of the gas mixtures. Next, for the presence of severe spectral line overlap in gas mixtures, the NN model is built based on the denoised spectral data. Finally, transfer learning is introduced into NN to improve the detection accuracy. The experimental results show that the sensor system can reliably achieve simultaneous online detection of NO, NH3, CS2, and SO2 at ppb level, and the average absolute errors of their measurements are 0.96 ppb, 1.27 ppb, 0.76 ppb and 0.97 ppb, with measurement accuracies of 3.5 %, 0.8 %, 0.5 % and 0.9 %, respectively.

Quantitative Analysis of Silicon Tetrachloride, Carbon Disulfide, and Dichloroethane Concentration by Raman Spectroscopy

Quantitative analysis of silicon tetrachloride, carbon disulfide, and dichloroethane concentrations to obtain vapor-liquid equilibrium data of the SiCl4-CS2 and SiCl4-C2H4Cl2 binary systems was established by Raman spectroscopy. The cheap glass sampling pipe was used as a carrier for Raman spectroscopy measurements. The Raman peak height of the internal standard was used to remove interference factors such as sampling pipe diameter, temperature, laser power, and other effects from the instrument. The peak height ratio between the Raman characteristic peak of the analyte and that of the internal standard was proportional to the analyte concentration. During the measuring process of vapor-liquid equilibrium data for the SiCl4-C2H4Cl2 binary system, the linear equation of y = 0.0068 + 0.75x with R2 of 0.9939 was used for the determination of SiCl4 concentration at the 422 cm−1 band. The linear equation of y = 0.0019 + 0.2266x with R2 of 0.9966 was used for the determination of C2H4Cl2 concentration at the 754 cm−1 band. For the SiCl4-CS2 binary system, the linear equation of y = 0.0494 + 4.7535x with R2 of 0.9962 was used for the determination of SiCl4 concentration at the 422 cm−1 band. The linear equation of y = 0.8139 + 8.7366x with R2 of 0.9973 was used for the determination of CS2 concentration at the 654 cm−1 band. The concentration of standard samples calculated by these standard curves was compared with the actual value to verify the accuracy of this method. The reproducibility is good when determining silicon tetrachloride and dichloroethane concentrations for the SiCl4-C2H4Cl2 binary system, with RSEP values of 2.81% and 2.17%, respectively. Meanwhile, the RSEP values are 3.55% and 4.16%, respectively, when determining silicon tetrachloride and carbon disulfide concentrations for the SiCl4-CS2 binary system.

Real-Time Measurement of SO2, H2S, and CS2 Mixed Gases Using Ultraviolet Spectroscopy and a Least Squares Algorithm.

Sulfur dioxide, carbon disulfide, and hydrogen sulfide are important decomposition products of insulating gas sulfur hexafluoride, and their types and contents are of great significance for the fault diagnosis of SF6 insulated equipment. In this paper, a method of combining ultraviolet absorption spectroscopy and least squares fitting is proposed for the quantitative calculation of sulfur dioxide, carbon disulfide, and hydrogen sulfide mixed gases. All three gases have absorption peaks in the ultraviolet band and they overlap with each other which makes it hard to determinate the concentrations of the three gases directly. During the experiment, we found that high concentrations of sulfur dioxide and carbon disulfide interfered with the hydrogen sulfide calculation and the magnitude of this interference was positively correlated with these two gas concentrations. Therefore, we found a modified equation for the correction of hydrogen sulfide. Combined with this equation, accurate quantitative detection of three gases can be achieved. The detection ranges are 0.5-10 parts per million for sulfur dioxide and hydrogen sulfide, and 10-300 parts per billion for carbon disulfide. This paper provides a simple and efficient detection method, which is convenient for integration into detection equipment and it provides a support method for the diagnosis of sulfur hexafluoride decomposition gases.

Measurement of CS2 Absorption Cross-Sections in the 188-215 nm Region at Room Temperature and Atmospheric Pressure.

Carbon disulfide, an important sulfur-containing species, has strong absorption lines in the wavelength range of 188 nm to 215 nm. It is difficult to accurately measure the absorption cross sections of carbon disulfide because carbon disulfide will be easily converted into carbon sulfide when it is exposed to ultraviolet light. In this study, the absorption cross sections of carbon disulfide were measured by reducing carbon disulfide conversion. The factors affecting carbon disulfide conversion, including gas flow rate, ultraviolet light intensity, and duration of illumination, were studied to reduce the conversion of carbon disulfide by controlling experimental conditions in the experiment. Finally, the absorption cross sections of carbon disulfide at room temperature and atmospheric pressure were calculated using the absorption spectrum and the carbon disulfide concentration in the absence of carbon disulfide conversion. The wavelengths of 16 absorption peaks on the carbon disulfide absorption cross sections of the vibration change were marked. Carbon disulfide has the maximum absorption cross section of 4.5 × 10-16 cm2/molecule at a wavelength of 198.10 nm.

Identification of the source of volatile sulfur compounds produced in milk during thermal processing

Volatile sulfur compounds in ultra-pasteurized (UP) milk are the major contributors to sulfur/burnt and eggy flavors, and these flavors are disliked by consumers. Previous research has established distinct differences in flavor profiles of fluid milk processed by high temperature, short time pasteurization (HTST) and UP by direct steam injection (DSI-UP) or indirect heat (IND-UP). An understanding of the contribution of the individual milk proteins to sulfur off-flavors would clarify the source of sulfur flavors in UP milks. The objective of this study was to determine the source of volatile sulfur compounds in fluid milk with a specific focus on the comparison of heat treatment effects on milks by HTST and UP. Formulated skim milks (FSM) were manufactured by blending micellar casein concentrate and serum protein isolate (SPI). Three different caseins as a percentage of true protein (FSM95, FSM80, and FSM60) were formulated to determine the source of sulfur/burnt and eggy flavors. Freshly processed micellar casein concentrate or SPI were blended to achieve a true protein content of about 3.2%. Raw skim milk served as a control. Skim milk and FSM were pasteurized at 78°C for 15 s (HTST) or 140°C for 2.3 s by IND-UP or DSI-UP. The experiment was replicated twice. Sensory properties of milks and FSM were documented by descriptive sensory analysis. Volatile sulfur compounds in milks and FSM were evaluated using solid-phase microextraction followed by gas chromatography-triple quadrupole mass spectrometry combined with a sulfur selective flame photometric detector. The FSM with higher SPI as a percent of true protein had higher sensory sulfur/burnt and eggy flavors along with elevated concentrations of hydrogen sulfide and carbon disulfide compared with skim milk or FSM with lower proportions of SPI. Sulfur compounds including dimethyl sulfide, dimethyl disulfide, dimethyl trisulfide, dimethyl sulfoxide, and methional were not associated with sulfur/burnt and eggy flavors, which suggests that these compounds may not specifically contribute to the sulfur/burnt and eggy off-flavors of UP milks. Sensory panelists found higher overall aroma impact, and cooked, sulfur/burnt, and eggy flavors for DSI-UP, followed by IND-UP and HTST. The combination of sensory and instrumental methods used in the current study effectively identified that milk serum proteins are the source of sulfur compounds in milk, and further confirmed the contribution of hydrogen sulfide and carbon disulfide to eggy and sulfur/burnt flavors, respectively.

Temporal and spatial distributions of carbonyl sulfide, dimethyl sulfide, and carbon disulfide in seawater and marine atmosphere of the Changjiang Estuary and its adjacent East China Sea

AbstractCarbonyl sulfide (COS), dimethyl sulfide (DMS), and carbon disulfide (CS2) concentrations were determined in seawater and the overlying atmosphere of the Changjiang Estuary and the adjacent area during two cruises from 22 February 2016 to 15 March 2016 and from 03 July 2016 to 25 July 2016. The concentration ranges of COS, DMS, and CS2 in seawater during winter were 121–388 pmol L−1, 0.321–1.59 nmol L−1, and 10.3–46.8 pmol L−1, respectively, and those during summer were 98–346 pmol L−1, 0.397–9.13 nmol L−1, and 13.3–65.4 pmol L−1. The DMS concentration in surface seawater varied seasonally, whereas the COS and CS2 concentrations varied little. The atmospheric mixing ratios of COS, DMS, and CS2 were 459–777 pptv, 5.2–96.8 pptv, and 96.9–164 pptv during winter and 417–644 pptv, 133–365 pptv, and 15.8–89.8 pptv during summer, respectively. A correlation analysis revealed that COS concentration was related to the concentrations of DMS and CS2. The estimated fluxes of COS, DMS, and CS2 were in the range of 1.19–2.06 μg m−2 d−1, 15.11–164.81 μg m−2 d−1, and 0.27‐1.32 μg m−2 d−1 during winter and 0.61–0.97 μg m−2 d−1, 71.76–2511 μg m−2 d−1, and 0.38–1.47 μg m−2 d−1 during summer, respectively. These results indicate that the study area is a sink for COS, but served as a source of atmospheric DMS and CS2 during the study period.

Necrotic enteritis challenge and high dietary sodium level affect odorant composition or emission from broilers.

Necrotic enteritis (NE) challenge and high dietary sodium (from sodium chloride) level on odor flux from broiler litter was investigated using 160 day-old Ross 308 male chicks randomly assigned to 4 dietary treatments with 4 replicates of 10 birds each. A 2 × 2 factorial arrangement of treatments was employed. Factors were: presence or absence of NE challenge and normal (1.6 g/kg) or high (4.0 g/kg) dietary sodium (Na) level. On d 20, odorants were collected from litter headspacewith a flux hood and measured using selected ion flow tube mass spectrometry (SIFT-MS). On d 33, while challenge did not lead to higher mortality, it reduced feed intake by 5.48% (P < 0.05) and body weight gain by 9.02% (P < 0.01) and worsened FCR by 5 points (P < 0.01), indicating subclinical necrotic enteritis occurred in challenged birds. Challenge increased (P < 0.01) litter moisture and litter headspace concentrations of dimethyl sulfide (P < 0.05), propyl mercaptan (P < 0.05), total butanols (P < 0.05), acetoin (P < 0.01), skatole (P = 0.05), butyric acid (P < 0.05), and methyl amine (P < 0.05) and tended to increase concentrations of ethyl mercaptan (P = 0.07), carbon disulfide (P = 0.09), indole (P = 0.10), and formic acid (P = 0.10) compared to the unchallenged group. The birds fed a high Na diet produced higher litter moisture (P < 0.01) and higher litter headspace concentration of sulfur compounds and phenol (P < 0.01) compared to those fed a normal Na diet. In the birds fed a high Na diet, challenge increased the litter flux of some additional odorants, which included 2,3-butanedione (P < 0.05), acetic acid (P < 0.01), propionic acid (P < 0.01), isobutyric acid (P < 0.01), isovaleric acid (P < 0.01), pentanoic acid (P < 0.05), 2-butanone (P < 0.05), and 3-methyl-1-butanol (P < 0.05). These findings suggest that both a high Na diet and sub-clinical NE increase the odor nuisance potential of broiler farms.

Use of carbon disulfide as attractant for trapping and rodenticide baiting of Bandicota bengalensis (GRAY)

Management of rodent with rodenticide and trapping is frequently ineffective due to bait or trap shyness and neophobia. A study was conducted in the laboratory of Vertebrate Pest Division, BARI, Gazipur and field to increase the attractiveness of bait or trap to B. bengalensis and enhance the consumption of novel food by using different concentration of carbon disulfide (CS2). Study revealed that addition of CS2 improved bait acceptance of food. Five ppm concentration of CS2, rat consumed significantly greater amount of cereal bait than untreated plain wheat bait. In semi-natural field test, significantly greater number (59%) of rat was trapped in CS2 scented bait than without scented bait (41%). In the field study higher population reduction (85-91%) was achieved with CS2 scented zinc phosphide bait than without scented zinc phosphide bait (50%). That is 80% higher reduction of rodent population was achieved with CS2 treated zinc phosphide bait. From this study we conclude that CS2 can improve the efficiency and consumption of poison bait and can increase trap success.SAARC J. Agri., 14(1): 93-101 (2016)

Effects of Fermi resonance of ν1 and 2ν2 on the Raman scattering of fundamental mode ν2 from liquid carbon disulfide

Raman scattering from liquid carbon disulfide has been studied for different concentrations in benzene. Modes ν1 (656cm−1) and 2ν2 (796cm−1) are allowed bands of carbon disulfide, while ν2 (396cm−1) is forbidden by the selection rules. However, a weak band has been observed along with the strong allowed totally symmetrical stretching mode ν1. The observation is ascribed to the effects of the vibrational anharmonicity of free molecule and intermolecular interaction potential. The ν1 and 2ν2 Fermi resonance can be influenced by the external conditions. The effects of the ν1 and 2ν2 Fermi resonance on the Raman frequency and relative intensity are discussed and the Raman scattering cross section of ν2 is studied for different concentration of carbon disulfide in benzene. The second-order perturbation quantum theory is introduced to explain the results that the Raman scattering of ν2 is influenced by 2ν2 and its Fermi resonance with ν1.

Treatment of municipal solid waste using an MBMB process coupled with biofiltration: control of odorous substance emissions

Mechanical–biodehydrated–mechanical–biological (MBMB) treatment is an enhanced waste treatment technology implemented in China to solve the high moisture content and incomplete degradation of garbage. This study investigated the release of regulated odorous gases in various stages in MBMB treatment and evaluated the performance of the biofilter in controlling such gases. Trimethylamine was not detected throughout the whole treatment. Hydrogen sulfide, methyl mercaptan, and methyl sulfide were undetected after biostabilization was achieved. A very low concentration of 0.039 mg/Nm3 styrene was detected on day 1 of biostabilization. After the MBMB treatment was administered, ammonia concentration decreased to 0.031 mg/Nm3, which is lower than 0.155 mg/Nm3 of the fresh household waste. Carbon disulfide concentration also decreased to approximately 50 %. The removal efficiencies of ammonia and hydrogen sulfide in the biofilter were 88.39 and 91.61 %, respectively. After biofiltration was completed, the outlet concentration of carbon disulfide was 0.017 mg/Nm3, which was only 1/20 of the fresh household waste. Volatile organic compounds, namely styrene, methyl mercaptan, and methyl sulfide, were undetected at the outlet of the biofilter. Therefore, the MBMB treatment coupled with biofilter can efficiently remove household waste pollutants.

The effects of pH and copper on the formation of volatile sulfur compounds in Chardonnay and Shiraz wines post-bottling

The effects of pH and Cu2+ treatment on the formation of volatile sulfur compounds (VSCs) were investigated in Chardonnay and Shiraz wine samples. Four VSCs were significantly affected by pH, with lower wine pH associated with decreased hydrogen sulfide (H2S), methanethiol, dimethyl sulfide, and carbon disulfide concentrations. The effects of pH and Cu2+ on H2S formation from known precursor compounds were subsequently studied in a model wine system. In samples treated with cysteine and glutathione lower pH produced less H2S. Nanoparticle tracking analysis was used to study the effects of variable pH concentrations in a model system containing Cu2+, tartaric acid, and H2S. Differences in Cu2+–tartrate complexes particle size and concentration were measured as a function of pH and H2S addition, suggesting the type of complexes formed may affect the binding sites of Cu2+ available to catalyse the formation of VSCs such as H2S.

Detection rate analysis on neurological sign of workers exposed to different concentrations of carbon disulfide

To study the effects of exposed to different concentrations of carbon disulfide on neurological signs of workers. Collection the information of concentration of carbon disulfide in the workplace or workers individuals exposed of a chemical fiber industry from 2004 to 2011, a total of 3 537 workers exposed to carbon disulfide were detected muscle strength and muscle tone, knee reflex, Achilles tendon reflex, trembling limbs, sensory function, and three chatter. Chi-square test was used for statistical analysis on abnormal neurological signs of workers. Eight hours time-weighted average concentration range of workers exposed to carbon disulfide in this chemical fiber industry was 0.2-41.0 mg/m(3), geometric mean was 2.38 mg/m(3). Concentration of carbon disulfide exposure of 1 771 workers was from 0.2 to 2.5 mg/m3( ≤ 2.5 mg/m(3)), 642 workers was 2.6-4.8 mg/m(3) (< 5.0 mg/m(3)), other 1 051 workers was from 5.1 to 41.0 mg/m(3) ( > 5.0 mg/m(3)) in all subjects. The different detection rates of knee reflex were 3.0% (31/1 045), 3.7% (21/574), 4.8% (16/331), 3.3% (10/305), 5.9% (11/187), 6.7% (68/1 022), the different detection rates of Achilles tendon reflex were 2.2% (23/1 045), 3.7% (21/574), 2.7% (9/331), 2.3% (7/305), 2.1% (4/187), 5.6% (57/1 022), the different detection rates of sensory dysfunction were 0.4% (4/1 045), 0.5% (3/574), 0.6% (2/331), 0.0% (0/305), 2.1% (4/187), 1.7% (17/1 022) in different cumulative amount of contact groups ( ≤ 10.0, 10.1-20.0, 20.1-30.0, 30.1-40.0, 40.1-50.0, >50.0 mg/m(3) per year), and the differences were statistically significant (χ(2) = 19.53, 21.27 and 15.89, all P values were <0.01) . Stratified according to age and gender, in addition to the ≤ 25 years group the difference of detection rate analysis on Achilles tendon reflex was statistically significant in the different concentration group (the ratio of on Achilles tendon reflex in the different groups of concentration of carbon disulfide exposure of 2.5, 2.6-5.0, ≥ 5.0 mg/m(3) were 0.4% (2/511), 1.0% (1/98), 2.1% (7/327), χ(2) = 5.59, P = 0.045) , the difference of detection rate analysis on neurological sign was not statistically significant in the different concentration group on the rest of the age and gender groups (P > 0.05). Within the concentration range of the object of study contact actual, different concentrations of carbon disulfide in addition to individual neurological signs of individual ages influential, it has no significant effect on the various signs of nervous system of workers of most age and gender groups, expect the age below the 25 years old group.

English

Biological desulfurization is a novel technology for the removal of hydrogen sulfide from some biogas or sour gas, in which there are always a certain amounts of carbon disulfide together with much hydrogen sulfide. Nowadays, carbon disulfide is found to have negative effect on the biological desulfurization, but seldom research is afforded to investigate how carbon disulfide inhibits the process of biological desulfurization. In this paper, we investigated the effect of carbon disulfide both on the growth of Thiobacillus thioparus and the resting cells under various concentrations, including 0.01, 0.05, 0.10, 0.15 and 0.20%. In this process, the rate of the cell growth was characterized by the rate of nitrogen consumption in order to solve the problem that the adsorption of cells to sulfur granules have on the accuracy of biomass test. Under the cell density of 23.92 mg N/L, which is lower than the maximum of cell density 36.13 mg N/L, the average rate of thiosulfate oxidation reached the maximum (26.50 S 2 O 3 2- mg/L-h). Carbon disulfide at titers of 0.01% significantly inhibited the growth of cells, but hardly affected the biological desulfurization of resting cells. Although carbon disulfide at titers of 0.05% had negative effect on the biological desulfurization of resting cells, the effect of inhibition could be relieved by the increased density of resting cells. For the resting cells, the parameters of Michaelis-Menten equation were calculated by the method of Lineweaver-Burk. The V max of biological desulfurization was decreased from 27.93 to 14.0 S 2 O 3 2- mg/L-h, and the K m was increased from 0.264 to 0.884 mM, with the concentration of carbon disulfide rising up from 0.0 to 0.1%. These results show that the growth of cells was sensitive to carbon disulfide, and the resting cells had resistance to the low level of carbon disulfide (0.05%). Thus, the inhibition of carbon disulfide to biological desulfurization should be attributed to T. thioparus growth suppression function. Keywords: Carbon disulfide, bio-desulfurization, inhibition, Thiobacillus thioparus , resting cell, gases purification African Journal of Biotechnology , Vol 13(16), 1739-1744

Grafting of Cellulose Extracted from Kenaf Using Xanthate Method

Mass spectra of reconstructed ion chromatogram (MRIC) technique are used to follow up the grafting copolymerization of 1-vinyl-2-pyrrolidinone (VP), 1-vinyl-3-anisylidine-2-pyrrolidinone (VAP) and ethylmethacrylate (EMA) and cellulose extracted from kenaf using xanthate method. Grafting is carried out under ionic and/or free radical mechanism conditions. Factors affecting grafting yield such as temperature, sodium hydroxide concentration, liquor ratio, carbon disulfide concentration, monomer and grafting time have been studied.

Simultaneous catalytic hydrolysis of low concentration of carbonyl sulfide and carbon disulfide by impregnated microwave activated carbon at low temperatures

The blank microwave coal-based activated carbons (MCAC) and blank microwave coconut shell activated carbons (MCSAC) were tested for simultaneous catalytic hydrolysis of carbonyl sulfide (COS) and carbon disulfide (CS2) at relatively low temperature (at 50°C). MCAC and MCSAC loaded by Fe–Cu–Ni metal mixed oxides were prepared by sol–gel method, and also tested for the simultaneous catalytic hydrolysis process. The results showed that Fe–Cu–Ni/MCSAC catalyst had the superior activity for the simultaneous catalytic hydrolysis of COS and CS2. These modified catalysts were characterized by XRD, BET, EDS and XPS, the results of which can help us to understand the reasons of the superior catalytic activity and the reasons of catalyst deactivation. Lower generation of sulfate (K3Na(SO4)2), high specific surface areas and more pore sizes of 0.3–1.2nm and 3.5–4.0nm may be the important role in COS and CS2 catalytic hydrolysis reaction. The XPS results showed that most of products on the exhausted catalysts were S/SO42- species which accumulated on the active carbon’s surface and had a negative effect on the hydrolysis activity, and the contents of S/SO42- species of exhausted Fe–Cu–Ni/MCAC were higher than which of exhausted Fe–Cu–Ni/MCSAC catalysts.

The rervising of biological exposure index for carbon disulfide exposuring

To study the biological exposure index of carbon disulfide in China. High-performance liquid chromatography (HPLC) was used to detect the levels of 2-thiothiazolidine-4-carboxylic acid (TTCA) in the urine of the workers after working shift end, Gas chromatography was used to detect the concentrations of the carbon disulfide in the workplace air. The relationship between the urine TTCA levels and the concentrations of the carbon disulfide was analyzed, the biological exposure index and judgement result from PC-TWA were compared. The levels of TTCA in urine of workers occupationally exposed to carbon disulfide were closely and positively related with the concentrations of the carbon disulfide in the workplace air. The regression equation was Y = 0.265X - 0.165, The biological exposure index of carbon disulfide were calculated by regression equation according to occupational exposure limits of carbon disulfide in China. The biological exposure index of CS(2) in China might be revised for 1.2 mg/g Cr.

Outbreak of Sudden Cardiac Deaths in a Tire Manufacturing Facility: Can It Be Caused by Nanoparticles?

ObjectivesThe purpose of this study was to review clinical characteristics and working environments of sudden cardiac death (SCD) cases associated with a tire manufacturer in Korea, and review possible occupational risk factors for cardiovascular disease including nanoparticles (ultrafine particles, UFPs).MethodsWe reviewed (i) the clinical course of SCD cases and (ii) occupational and non-occupational risk factors including chemicals, the physical work environment, and job characteristics.ResultsPossible occupational factors were chemicals, UFPs of rubber fume, a hot environment, shift work, overworking, and noise exposure. The mean diameter of rubber fume (63-73 nm) was (larger than diesel exhaust [12 nm] and outdoor dust [50 nm]). The concentration of carbon disulfide, carbon monoxide and styrene were lower than the limit of detection. Five SCD cases were exposed to shift work and overworking. Most of the cases had several non-occupational factors such as hypertension, overweight and smoking.ConclusionThe diameter of rubber fume was larger than outdoor and the diesel exhaust, the most well known particulate having a causal relationship with cardiovascular disease. The possibility of a causal relation between UFPs of rubber fume and SCD was not supported in this study. However, it is necessary to continue studying the relationship between large sized UFPs and SCD.

Investigation of lung cancer biomarkers by hyphenated separation techniques and chemometrics

Volatile organic compounds (VOCs) present in breath of lung cancer patients and released by lung cancer cells were determined. As a reference sample breath collected from healthy volunteers and lung segments of cells with proper morphology were used. Solid phase microextraction and gas chromato-graphy mass spectrometry (SPME-GC/MS) method was applied for VOC analysis. Statistical methods have been developed to find similarities between patterns of investigated compounds within three populations of samples: exhaled air samples from patients with lung cancer, headspace of lung tissues with healthy and cancer cells. Quantitative analysis of VOCs in the headspace of lung tissues revealed that cancer cells released higher concentrations of ethanol, acetone, carbon disulfide, dimethyl sulfide, 1-propanol, 2-propanol, 2-butanone and 2-pentanone than healthy tissues. The increase of concentration of the same compounds was observed in the breath of patients with lung cancer in comparison to breath from healthy non-smoking volunteers. Detection of lung cancer is possible by volatile biomarkers analysis in breath.

Development of a gas chromatography — mass spectrometry method for the determination of carbon disulfide in the atmosphere

Carbon disulfide (CS2), a relevant reduced sulfur compound in air, is well-known for its malodor and its significant effect on global atmospheric chemistry. Therefore, a reliable method for determining CS2 in atmospheric samples has been developed based on solid-phase sampling and gas chromatography–mass spectrometry (GC–MS). Two types of solid-phase sampling supports (Orbo-32 and SKC) and the elution with organic solvents — hexane and toluene — were evaluated for low-volume outdoor sampling. Recovery studies and the standard addition method were carried out to demonstrate the proper determination of CS2 in the absence of the influence of interferences such as ozone, hydrogen sulfide or water — important atmospheric pollutants —. The proposed methodology was validated by performing experiments in a high-volume smog chamber and by comparison with two reference optical methods, Fourier Transform Infrared (FTIR) and Differential Optical Absorption Spectroscopy (DOAS) installed in these facilities. Satisfactory analytical parameters were reported: fast analysis, a correct repeatability of 6±1% and reproducibility of 14±3%, and low detection limits of 0.3–0.9pgm−3. Finally, the method was successfully applied to industrial samples near a pulp factory area, where a high correlation between industrial emissions and reported carbon disulfide concentrations were observed.

Pesticide residues in grapes and during vinification process

Pesticide residues in vinification process of two white and two red grapevine varieties were monitored during the 2007 vintage. Crushed grapes, cake, must, lees and wine were sampled during the vinification process. Additionally, grapes were sampled during the ripening process. All samples were taken in triplicate and analyzed for the presence of 117 pesticides. The pesticide residues were determined by three validated internal analytical methods: the multi-residual GC-MS method (71 pesticides), the multi-residual LC-MS-MS method (45 pesticides) and GC-MS method for the determination of dithiocarbamates (the sum of their concentrations is given as a concentration of carbon disulfide). Boscalid and phosalone were the most persistent pesticides in grapes during ripening. The concentrations of pesticide residues in must and wine were significantly diminished through separations during the solid and liquid phases of the vinification process, particularly the pressing of crushed grapes and wine racking after alcoholic fermentation. The pesticides detected throughout the vinification process were boscalid, cyprodinil, dimethomorph, fenhexamid, metalaxyl and procymidone and their concentrations in the wines were 0.01–0.02, 0.04, 0.01–0.08, 0.12–0.13, 0.09–0.11 and 0.07–0.13 mg L −1 respectively.