Determination of Total Sulfur in Soils and Plants by an Automated Dry Combustion Method

Abstract

Determination of total sulfur in environmental samples can be accomplished using automated dry combustion techniques. The analytical performance of an elemental analyzer (CE Instruments) was compared with a method involving dry ashing followed by ion chromatographic detection of sulfate (IC). Samples included certified reference materials, confirmation materials with a known content of sulfur, and several soils and plants. There was a close agreement between both methods. Superior accuracy, precision and detection limits were obtained using the dry combustion method. Current results suggest that the automated dry combustion technique has developed into an adequate method for the determination of the relatively low total sulfur contents commonly encountered in soils and plants.     

Determination of Sulfur Compounds in Air by Chemiluminescence

Abstract

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.     

Correlation between Electron Capture Response and Chemical Structure for Sulfur Compounds

Abstract

The temperature dependence of the electron capture process was investigated for a series of divalent sulfur compounds. The electron affinity and/or the activation energy for the electron capture reaction were calculated for individual compounds by plotting In KT^3/2 vs. 1/T, where K is the electron capture coefficient and T is the absolute temperature in the detector. The correlation between these values and chemical structure was discussed by means of 3d orbital resonance of the sulfur atom.     

Determination of Sulfur in Trace Amounts

Abstract

An absolute method for the determination of trace amounts of sulfur in water and organic matrices is described. The method involves decomposition of organic samples in an oxygen bomb or oxidation of water samples with hydrogen peroxide. The resultant sulfates are reduced and distilled as hydrogen sulfide by the action of stannous phosphate in anhydrous phosphoric acid. The evolved hydrogen sulfide is absorbed in zinc acetate solution, converted to methylene blue and measured spectrophotometrically at 665 mm. The range is from 2 to 40 μg of sulfur using 1 cm cells.     

Changes in Reduced Gaseous Sulfur Compounds Collected in Glass Gas Sampling Bulbs

Abstract

Changes which volatile reduced sulfur species (hydrogen sulfide, carbonyl sulfide, methanethiol, dimethyl sulfide and carbon disulfide) undergo in glass gas sampling bulbs were determined as influenced by the balance gas matrix and moisture. Results have shown that differences in reduced sulfur gas concentrations compared with the initial values were less than 5% in each sulfur compounds within 24 hours if the balance gas was dry nitrogen. There was no change in composition if dry air sample was measured within 3 hours. Significant decrease in hydrogen sulfide and methanethiol concentrations was observed with a short period of time following sampling if moisture was present within the bulb atmosphere.     

Determination of Sulfur in Hydrocarbons by Oxidative Pyrolysis and Microcoulometric Titration

Abstract

Conditions are described which give 95%+ conversion of sulfur to sulfur dioxide in an oxidative pyrolysis - microcoulometric determination of sulfur in hydrocarbons. There is no significant variation in combustion efficiency due to matrix effects or type of sulfur compound present. Samples containing from 0.1 to 500 ppm sulfur may be run without dilution. The mean relative standard deviation over this range is about 2.5%.     

Microcoulometric Determination of Sulfur and Chlorine by Combustion and Nitrogen by Hydrogenolysis

Abstract

The design of an improved open microcombustion tube and experimental conditions for the rapid, accurate and precise determination of sulfur and chlorine by microcoulometry are described. The design and operating conditions for a catalytic hydrogenolysis tube and scrubber tube for acid removal are also presented for the determination of nitrogen. Examples of the application of the above methods for these elements in petroleum and petrochemicals are presented.     

The Behavior of Certain Coumarins and Furocoumarins Toward Sulfur Reagents

The behavior of 4-hydroxycoumarin (1), 7-hydroxycoumarin (2), 4-hydroxy-bergapten (3), and 4-hydroxyisopimpinellin (4) toward sulfur reagents, namely, thionyl chloride, phosphorus pentasulfide, thiolacetic acid, and Lawesson's reagent (5), was studied. The nature of products in each case depended upon the type of reactants and reaction conditions. Possible reaction mechanisms were considered, and structural elucidations of the new products were based upon compatible elementary and spectroscopic evidences.     

High Pressure Liquid Chromatography of Selected Sulfur Compounds

Abstract

High pressure liquid chromatography was used to separate and determine quantitatively the following groups of sulfur compounds: thiols, sulfides, disulfides, sulfones, isothiocyanates, thioamides, and thioureas. Amperometric and UV detectors were compared; for thiols, thioureas, isothiocyanates, and thioamides, the former was generally more sensitive. With the exception of alkyl and cycloalkyl sulfides, the liquid chromatographic method can be used for the analysis of the investigated sulfur compounds below the ppm range. The method developed was compared to gas chromatography with flame photometric detection. The latter was found to be superior for the analysis of alkyl and cycloalkyl thiols, sulfides and disulfides of molecular weight below 200, whereas the former was more suitable for the analysis of aromatic thiols, sulfides and disulfides, as well as thioamides, isothiocyanates, and thioureas. Both methods were equivalent for the analysis of aromatic sulfones.     

Pneumatoamperometric Determination of Sulfur Dioxide in Air on ppb Level

Abstract

A simple device for the determination of sulfur dioxide at ppb concentrations in air is described. The device is composed of an enrichment unit operating continuously on the basis of gas extraction into polydisperse aerosol of a liquid transferring sulfur dioxide from liter amount of air into microliter amount of liquid. The analyte is determined pneumatoamperically from the concentrate on a gold-plated porous Teflon electrode.

The detection limit is 0.3 ppb (v), i.e. 0.87 μg/m³ of sulfur dioxide, the linear range covers several orders of magnitude. The analytical response is obtained few tenths of seconds after the gas contaminated with sulfur dioxide has entered the enrichment unit     

The Detection of Source Levels of Sulfur Dioxide Using a Piezo-Electric Detector and Permeation Membrane

Abstract

The detection of gaseous pollutants using a coated vibrating quartz crystal has been the topic of several studies. Detection of sulfur dioxide with an alkanoamine-coated crystal has already been shown feasible for ambient air pollution levels. Detection of sulfur dioxide at source levels using the piezo-electric method has previously not been proven successful. This work presents the refinements, calibration, and performance of a source monitoring instrument which incorporates a sulfur dioxide permeable membrane as a dilution interface.     

Analysis of Total Non-Volatile Non-Sulfide Reduced Sulfur in Potable and Untreated Surface and Groundwaters

Abstract

An analytical method was developed to measure the total concentration of non-volatile non-sulfide reduced sulfur in treated and untreated surface and groundwater. The method was based on the alkaline reduction by Raney nickel (prepared in situ from Raney alloy) of organic and inorganic sulfur compounds (in oxidation states below +6) to sulfide. Sulfide was swept out of the reflux apparatus under nitrogen into a trap of zinc acetate and determined colorimetrically as ethylene blue. The recoveries obtained from solutions of elemental sulfur, sulfide, sulfite, thiosulfate, tetrathionate, cysteine, cystine, methionine, glutathione, allylthiourea, sulfanilamide and thiocyanate ranged from 84–102% with typical recoveries of approximately 90%. Sulfate was not detectable by the procedure. Chlorine present in potable water samples interfered in the procedure and was removed with sodium borohydride. The relative standard deviation of the method varied from 0.25 to 5.6% and averaged 3%. The detection limit based on a 500 mL sample was 3 mg m^?3.     

Molecular Simulation to Explore the Dissolution Behavior of Sulfur in Carbon Disulfide

Soluble sulfur (S₈) and insoluble sulfur (IS) have different application fields, and molecular dynamics simulation can reveal their differences in solubility in solvents. It is found that in the simulated carbon disulfide (CS₂) solvent, soluble sulfur in the form of clusters mainly promotes the dissolution of clusters through van der Waals interaction between solvent molecules (CS₂) and S₈, and the solubility gradually increases with the increase in temperature. However, the strong interaction between polymer chains of insoluble sulfur in the form of polymer hinders the diffusion of IS into CS₂ solvent, which is not conducive to high-temperature dissolution. The simulated solubility parameter shows that the solubility parameter of soluble sulfur is closer to that of the solvent, which is consistent with the above explanation that soluble sulfur is easy to dissolve.     

Electroanalytical Chemistry of Sulfur Compounds For the New Coal Conversion Technologies

Abstract

Polarographic methods are described “tailor-made” for the speciation and determination of sulfur contaminants in synfuels and coal gasification/liquefaction process streams. In samples containing the anions, S^2? _x, sulfidic sulfur was quantitated by anodic depolarization of the dropping mercury electrode, while polysulfidic sulfur was determined with the aid of an electroreduction process implicating 2(x-1) electrons. Polythionates were electroreduced to thiosulfate, sulfite, sulfide and/or mixtures thereof, under judiciously controlled experimental conditions. Thiosulfate and sulfite were quantitated by differential pulse polarography at dropping mercury anodes via reactions involving formation of thiosulfato- and sulfitomercurates.     

矿山酸性水中硫的化学状态分析

本文主要讨论用双晶高分辨X-射线荧光光谱法和SULS程序解析硫的化学状态，并用本方法初步研究了德兴铜矿黄铁矿型废石风化产生的酸性水中硫的化学状态。用人工试样测定并解析表明，其分析相对误差对于S^2-和S^0小于6％，对于S^4 和S^6 小于16％。德兴铜矿酸性水刚露出地表时，水中的硫主要以四价形式存在，在露出地表与空气接触后，四价的硫很快被空气中氧氧化成六价。     

Developments of Asymmetric Synthesis Mediated by Chiral Sulfur Reagents

Abstract

Our work on the thio-Claisen rearrangement mediated by an adjacent sulfinyl group is reviewed. The substrates could easily be prepared on a large scale from diacetone-D-glucose. The rearrangement was effected with a diastereoselectivity of 95:5, in favor of the (S,S) or the (R,R) isomer. An approach to natural bis(lactones) was investigated, using a halolactonization reaction and a second [3,3] sigmatropic shift, again mediated by the sulfinyl group. The second part deals with the catalytic enantioselective benzylidenation of aldehydes, mediated by chiral sulfur ylides. We have introduced simple C ₂ symmetric thiolanes for that purpose. The procedure is very practical and enantiomeric excesses up to 96% have been reported for the model of stilbene oxide. A series of ferrocenyl sulfides with planar chirality has also been investigated, leading to unexpected diastereoselectivities and enantiomeric excesses up to 94%.     

Determination of Nitrogen,Sulfur, Phosphorus,and Carbon in Solid Ecological Materials Via Hydrogenation and Element-Selective Detection

Abstract

Element-selective detectors for carbon, sulfur, phosphorus, and nitrogen are used to determine methane, hydrogen sulfide, phosphine and ammonia in the effluent from a pyrolytic hydrogenator. Solid ecological field samples, e.g., forest floor litter, plant stream particulate, and insects, require no chemical pretreatment. These are pyrolyzed and the pyrolyzates pass through a catalyst bed which reduces the elements to the corresponding hydrides. Data are given for sulfur, carbon, and nitrogen.     

高频红外碳硫分析仪测定石膏矿中的三氧化硫

利用高频红外碳硫仪对石膏矿中三氧化硫含量的测定进行了研究,取得了较好的结果.方法检出限为0.003 0%.用石膏标准样品(GBW03109a,GBW03110)进行分析,测定值与认定值相符,测定值的相对标准偏差(n=9)在0.32%~0.81%之间.使用石膏标准样品(GBW03111)进行本法与国标硫酸钡重量法做比对试验,测定结果无显著性差异.加标回收率为96.4%~104.0%.     

Technical Syntheses of Sulfur Containing Amino Acids

Abstract

About 25% of the total production of amino acids world wide are sulfur containing amino acids. The applications, the technical syntheses and production methods are discussed with selected examples.