Determination Of Sulfur Compounds Research Articles

Determination of sulfur compounds in biological desulfurization system by high performance liquid chromatography

Biological desulfurization is a process in which sulfur compounds are removed from gas and oil using microorganisms. It is a simple process that has mild operating conditions, high desulfurization efficiency, low energy consumption and less environmental pollution. However, there is still a lack of simple and efficient analytical methods for quantitatively analyzing the sulfur compounds in the biological desulfurization process. In order to solve this problem, the analytical method for the simultaneous determination of sulfite, thiosulfate and sulfide in biological desulfurization solutions by pre-column fluorescence derivation using high performance liquid chromatography (HPLC) was developed. The standard curves of sulfur species in this analytical method had good linear relationships with correlation coefficients of 0.999 5, 0.999 7, and 0.999 7 for sulfite, thiosulfate and sulfide, respectively. The detection limits of these sulfur compounds were 0.000 6, 0.000 7 and 0.001 1 μmol/L; the range of recovery rates were 98.17 to 101.9%, 100.9 to 102.6%, and 101.1 to 104.2%; which had good repeatability and stability. The analytical method was simple, efficient and accurate, and could be used to simultaneously determine the sulfur compounds in different biological desulfurization systems.

Preliminary analysis of bioactive components in aqueous garlic extract

Limited analysis of bioactive components of garlic (Allium sativum) extracts by GC‐MS as well as analysis of amino acid and fatty acid composition and trace metal analysis were carried out. The total phenol content of garlic was 0.374 mg/g dry weight. GC‐MS determination of sulfur compounds in fresh garlic extract and fresh chopped garlic revealed similar compositions with vinyl dithins being the major component in both (40% and 46% respectively), with lesser amounts of allylmethyl trisulfide, diallyl disulfide and S‐allyl cysteine. Freezing and storage of garlic extract resulted in increased amounts of S‐allylcysteine and diallyldisulide, and decreased levels of allylmethyl trisulfide. Vinyldithins remained at approximately 40% throughout the storage period. Boiling of garlic extract vastly changed the composition with allylmethyl disulfide, allyl alcohol and dimethyl disulfide being the major components. Amino acid and metal analysis of garlic extract revealed the presence of 17 amino acids and potassium as the major metal. Fourteen fatty acids were identified in garlic extract with the major fatty acids identified as palmitic, linoleic and stearic acids;A major bioactive component from garlic extract, S‐allyl cysteine (SAC), was purified by preparative HPLC and assessed for biological activity in streptozotocin (STZ) ‐ induced diabetic rats during a 4 week daily treatment experiment. SAC (5mg/kg daily intraperitoneally) was shown to be effective in limiting weight loss and lowering blood glucose levels of diabetic rats. However, SAC was effective in decreasing polyphagia and polydipsia typical of diabetic rats.Support or Funding InformationThe study was supported by KU grant #SL 07/14.

РАЗРАБОТКА МЕМБРАННЫХ СЕНСОРОВ НА ОСНОВЕ НОВЫХ ГИБРИДНЫХ МАТЕРИАЛОВ ДЛЯ ОПРЕДЕЛЕНИЯ СЕРОСОДЕРЖАЩИХ И ЛЕКАРСТВЕННЫХ ВЕЩЕСТВ В ХОЗЯЙСТВЕННО-БЫТОВЫХ И ПРОМЫШЛЕННЫХ СТОКАХ

Developed potentiometric PD sensors with new hybrid materials based on perfluorinated sulfokationoobmennyh mem-branes Nafion and MF 4SK contain-ing nanoparticles of hydrated metal oxide (including a functionalized surface) to quant-tively determination of sulfur compounds and is widely used in medical practice, local anesthetic agents (procaine, lidoka-in) in multicomponent aqueous media. Using sensors in the similarity-tion of composite materials can significant-ly increase their Chuv-tivity to define the components that helps to increase the accuracy of determination.. Easy to use, no sample preparation, automatic pro-cessing of data portability obespe Chiva-low labor intensity analysis, which makes available to develop mye-touch devices for a wide range of control organi-zation-tions and services for environmental monitoring of water flows of medical institutions and industrial enterprises.

Air pollution in landfill of wastes other than hazardous or inert / Zanieczyszczenia powietrza na składowiskach odpadów innych niż niebezpieczne i obojętne

Abstract Microbiological and chemical analysis of air was carried out on the area of landfill of wastes other than inert or hazardous. The landfill covers 20 ha and 40 000 Mg of wastes is deposited annually. Municipal waste is not segregated at the landfill. The research was conducted in April, May and November 2012. Number of the psychrophilic and mesophilic bacteria and fungi was estimated by a culture-based method. Quantitative determination of sulfur compounds and meteorological and olfactrometric examinations were also carried out. Chemical analysis was conducted with a Photovac Voyager portable gas chromatograph. Air samples were collected at 5 points. The largest group of microbes were psychrophilic bacteria, especially in summer. The highest concentration of hydrogen sulfide and other odorants was found at leachate tank and landfill body. According to the Polish Standard for the assessment of atmospheric air pollution the air in the area of the landfill is classified as not contaminated and sporadically moderately contaminated. In spring and summer the number of microscopic fungi was increased also in control samples.

Comparison of Methods for the Sulfur Compounds and Elemental Sulfur Analysis in High-Sulfur Natural Gas

Some gas fields with high hydrogen sulfide content, such as Luojiazhai, Dukouhe and Puguang Gas Fields, are found in Northeast Sichuan. For exploring and utilizing high sulfur natural gas reservoirs, it is essential to quantificational analysis of sulfur compounds and elemental sulfur in high sulfur natural gas. Determination of hydrogen sulfide content in natural gas with a laser method has many advantages, including on-site measurement, fast response, wide application scope, high accuracy, high reliability, and low maintenance. When the hydrogen sulfide concentration is 1% to 20%, the relative deviation of the analysis value to the standard value is less than 3% with repeatability of less than 1%. Determination of sulfur compounds in natural gas by gas chromatograph with sulfur chemiluminescence detector (SCD) also has many advantages, such as it is simple, fast, accurate and free from interference of most sample matrixes. The analysis method has good repeatability with lower limit of detection. Since SCD has liner equimolar response to sulfur atom, only one reference gas mixture of sulfur compound is used as external standard calibration. Determination of total sulfur content in natural gas with oxidative microcoulometry method has good repeatability and high accuracy. Determination of elemental sulfur by liquid chromatography has repeatability better than 3%, the detection limit is 10mg/m3, and recovery rate of over 90%, and is applicable for determination of elemental sulfur content in high sulfur natural gas.

Determination of Sulfur Compounds in Water Samples by Ion Chromatography Dynamic Reaction Cell Inductively Coupled Plasma Mass Spectrometry

AbstractAn ion chromatography‐inductively coupled plasma mass spectrometric (IC‐ICP‐MS) method for the speciation of sulfur compounds, namely sulfite [SO32−], sulfate [SO42−] and thiosulfate [S2O32−], was described. Ionic sulfur compounds were well separated in about 3 min by ion chromatography with a Hamilton PRP‐X100 column as the stationary phase and 60 mmol L−1 NH4NO3 and 0.1% v/v formaldehyde (HCHO) solution (pH = 7) as the mobile phase. The analyses were carried out using dynamic reaction cell (DRC) ICP‐MS. The sulfur‐selective chromatogram was determined at m/z 48 as 32S16O+ by using its reaction with O2 in the reaction cell. The method avoided the effect of polyatomic isobaric interferences at m/z 32 caused by 16O16O+ and 14N18O+ on 32S+ by detecting 32S+ as the oxide ion 32S16O+ at m/z 48, which is less interfered. The detection limit of various species studied was in the range of 3.6–4.6 ng S mL−1. The accuracy of the method has been verified by comparing the sum of the concentrations of individual sulfur compounds obtained by the present procedure with the total concentration of sulfur in several natural water samples. The recovery was in the range of 97–102% for various compounds studied.

Rapid Determination of Low-Level Sulfur Compounds in Beer by Headspace Gas Chromatography with a Pulsed Flame Photometric Detector

Off-flavors in beer are frequently due to the presence of sulfur compounds. A simple and sensitive method for the analysis of volatile sulfur compounds in beer at trace levels was developed using headspace gas chromatography with a pulsed flame photometric detector. Different capillary columns were tested, and a 60-m nonpolar DB-1 capillary column was found to be the most appropriate. Four sulfur compounds, including hydrogen sulfide, methanethiol, ethanethiol, and dimethyl sulfide, could be quantified simultaneously using ethyl methyl sulfide as the internal standard. Calibration curves were established in a 4% (vol/vol) ethanolic solution with pH adjusted to 4.0; linear correlation coefficients (r) were greater than 0.99 for all target compounds. This method enables four sulfur compounds in beer to be determined at trace levels, with recoveries greater than 96%, a repeatability error of less than 5%, and limits of detection between 0.1 and 2 μg/L. The overall method was successfully applied to the determination of sulfur compounds studied in several beers.

Determination of Sulfur Compounds in Hydrotreated Transformer Base Oil by Potentiometric Titration

A method was developed to analyze the distribution of sulfur compounds in model sulfur compounds by potentiometric titration, and applied to analyze hydrotreated transformer base oil. Model thioethers were oxidized to corresponding sulfoxides by tetrabutylammonium periodate and sodium metaperiodate, respectively, and the sulfoxides were titrated by perchloric acid titrant in acetic anhydride. The contents of aliphatic thioethers and total thioethers were then determined from that of sulfoxides in solution. The method was applied to determine the organic sulfur compounds in hydrotreated transformer base oil.

Semiconducting Electrodes for Determination of Sulfur Compounds in Gas Condensates

New electrodes with semiconducting membranes distinguished by elevated chemical resistance in aggressive media, mechanical strength, and a long lifetime are proposed as indicator electrodes. A method is developed for successive potentiometric determination of mercaptans and sulfides from one sample of condensate using an indicator pair consisting of semiconducting and platinum electrodes. The method is characterized by accuracy, speed, and reliability.

Determination of odorous sulfur compounds in air by Tenax GR preconcentration and capillary gas chromatography in combination with flameless sulfur chemiluminescence detection

A liner of PTV injector packed with the solid adsorbent Tenax GR was used to enrich ambient levels of volatile sulfur compounds, then the sulfur gases were thermally released according to programmed temperature from Tenax GR trap and re‐collected in a column cooled with liquid nitrogen. The sulfur compounds were revolatilized and directly transferred to the system of capillary‐column gas chromatography/flameless sulfur chemiluminescence detector for analysis. The PTV injector has been used as a thermal desorption chamber for determination of sulfur compounds. The sulfur gaseous compounds known to cause nuisance odors in the air from sewerage treatment tanks of a chemical petroleum company and hoggery are determined.

Determination of sulphur compounds in beer using headspace solid-phase microextraction and gas chromatographic analysis with pulsed flame photometric detection

A simple and sensitive method for the analysis of volatile and semi-volatile sulphur compounds in beer at trace levels was developed using headspace solid-phase microextraction (SPME) and gas chromatography with pulsed flame photometric detection. Different SPME fibres were tested and a Carboxen–polydimethylsiloxane coated fibre was found to be the most appropriate. The adsorption and desorption conditions were optimised. The effect of ethanol concentration in the sample on the extraction of analytes was examined. A 60 m non-polar capillary column preceded by a 10 m length of a polar column was found to be capable of separating a wide range of C 1–C 6 sulphur compounds. The pulsed flame photometric detector enabled increased sensitivity to be obtained over previous methods, such as dynamic headspace followed by conventional flame photometric detection or sulphur chemiluminescent detection, with high sulphur selectivity. Two sulphur compounds, 2-methyl-1-butanethiol and 3-methylthiophene, were identified in beer for the first time.

Chemiluminescent methods in alcoholic beverage analysis.

Chemiluminescent (CL) techniques employed in alcoholic beverage analysis are summarized. Specific applications to wine, beer, brandy, and tequila are described, and the determination of sulfur compounds, phosphate, L-malate, glycerol, fatty acids, phenolic compounds, and urate is included. Possibilities and limitations of the various CL detection systems are evaluated.

Determination of sulfur compounds in the sol–gel processing of GeS 2 by potentiometric titration

The potentiometric titration method was used for quantitative determination of germanium sulfide and germanium mercaptide evolved during the sol–gel processing of GeS 2 from germanium ethoxide and H 2S. The titrations were performed in 2-propanol or in a 50–50 vol.% mixture of 2-propanol and toluene. The ion selective Ag/Ag 2S electrode was used for equivalence point detection. Study of the Nernst equation shows that complexes were formed at the electrode surface. However, the titration equivalence point volume clearly demonstrates the formation of Ag 2S and Ge(SAg) n . In order to explain this discrepancy, a new electrode reaction mechanism is suggested and a modified Ag/Ag 2S electrode potential equation is proposed.

Determination of Sulfur Compounds in Air by Chemiluminescence

The present review is devoted to applications of chemiluminescence to the analysis of trace sulfur species in air. Determinations of oxidized (sulfur dioxide and sulfite), reduced (hydrogen sulfide, dimethyl sulfide, carbonyl sulfide, carbon disulfide and mercaptans) and/or sulfur compounds in general are described and some practical considerations are discussed. The development of detectors based on chemiluminescence in the aproximately last fifteen years is also reviewed.

97/04494 Determination of sulfur compounds in non-polar fraction of vacuum gas oil: Ma, X. et al. Fuel, 1997, 76, (4), 329–339

97/04494 Determination of sulfur compounds in non-polar fraction of vacuum gas oil: Ma, X. et al. Fuel, 1997, 76, (4), 329–339

Determination of sulfur compounds in non-polar fraction of vacuum gas oil

Sulfur compounds in the non-polar fraction, which represents 73 wt% of total sulfur in a vacuum gas oil (VGO), were analysed by sulfur-selective ligand exchange chromatography combined with high-performance liquid chromatographic (h.p.l.c.) separation on the basis of aromatic ring number, with subsequent capillary g.c.-mass spectrometry for identification. Quantification was achieved by independent h.p.l.c. separation based on aromatic ring number followed by capillary gas chromatography with a sulfur-selective flame photometric detector. These methods were very effective in isolating the sulfur compounds from complex mixtures of high-boiling hydrocarbon compounds and for separating the sulfur compounds according to aromatic ring number. The structures and concentrations of > 100 sulfur compounds in the non-polar fraction of the VGO were determined Alkyl benzo[ b]thiophenes, dibenzo[ b,d]thiophenes, benzonaphthothiophenes and phenanthro[4,5- b,c,d]thiophenes were found to be major sulfur species existing in the non-polar fraction of the VGO.

Molecular States of Sulfur Compounds in the Gasphase, in Solution and in Crystals

Abstract The molecular states of selected sulfur compounds are summarized for the first time using the qualitative model approach based on topology, symmetry, effective nuclear potentials as well as electron distribution and supported by quantum chemical calculations to rationalize and to predict structure/energy relations coupled by dynamics. Topics discussed comprise: (i) The gasphase preparation of numerous short-lived sulfur compounds such as H2C[dbnd]S, SN, SSO, HNSO, HC[dbnd]C-HC[dbnd]S and H2C[dbnd]CH-HC[dbnd]S, RP[dbnd]S or RP([dbnd]S)2) and their characterization by radical cation state fingerprints. (ii) Radical ion generation of sulfur-containing species such as Rπ(SR)n •⊕/⊖, S2(CH2)3 •⊕ or R2NSSNR2 •⊕ in solution by favorable AlCl3/H2CCl2 oxidation or metal mirror reduction and their characterization by ESR/ENDOR spectroscopic signal pattems. (iii) Growth of molecular crystals and structure determination of sulfur compounds and their ion salts such as the halogen charge transfer complexes {(Rπ...

Application of catalytic stripping voltammetry for the determination of organic sulfur compounds at a hanging mercury drop electrode: behaviour of cysteine, cystine and N-acetylcysteine in the presence of nickel ion

The differential-pulse cathodic stripping voltammetry of cysteine (CysH), cystine (Cys) and N-acetylcysteine (Ac-CysH) was studied at a hanging mercury drop electrode at pH 7 in the presence of nickel ion, 3-(N-Morpholino)propanesulfonic acid (MOPS) and phosphate–acetate buffer were used as supporting electrolytes. In the presence of CysH, after accumulation at potentials ranging between 0.0 and –0.4 V, the catalytic reduction of nickel ion gives a peak at –0.6 V versus the Ag—AgCl reference electrode. An additional effect of nickel ion is the suppression of the cathodic stripping peak due to mercury cysteinate reduction, thus permitting the simultaneous determination of another thiol with no catalytic activity (e. g., Ac-CysH), Consequently, CysH (or Cys) and Ac-CysH can be determined simultaneously or independently in the same sample. Cys is reduced at potentials preceding the catalytic peak, which is actually due to the CysH thus produced. Some differences between the behaviour of Cys and CysH are due to different accumulation mechanisms. The catalytic stripping voltammetry of CysH or Cys exhibits good sensitivity (detection limit about 1 nmol dm–3 for 3 min accumulation). The stripping voltammetric method described appears to be the first involving adsorptive accumulation of a metal complex in which the organic ligand is determined catalytically. Further, this particular method affords some selectivity in the determination of sulfur compounds, which are normally determined by cathodic stripping, voltammetry of their anodically accumulated mercury complexes.

Determination of sulphur compounds in Iraqi natural gasoline

Characterization of sulphur constituents of natural gasoline was performed using chemical methods of abstraction of sulphur containing groups, followed by gas liquid Chromatographic separation with flame photometric detection for the determination of individual sulphur compounds. Three thiols and fourteen disulphides have been identified.

Determination of sulphur compounds by fully automated molecular emission cavity analysis

The performance of an automated molecular emission cavity analysis (MECA) instrument for the determination of sulphur compounds was investigated. Thiourea, sulphuric acid, ammonium thiocyanate and promethazine were chosen as model compounds. The control of the time required for the various sectors of the MECA operation (time spent in flame, cooling time before sample injection and solvent pre-evaporation time) allows conditions of greatest sensitivity or reproducibility to be established. If complete solvent evaporation is possible before cavity introduction into the flame, sensitivity and calibration linearity are greatly improved. The automated instrument also allows an assessment to be made of the simultaneous determination of thiocyanate and sulphate.