Determination Of Elemental Sulfur Research Articles

Determination of Elemental Sulfur from S-Rich Soil and Fertilizer by Titrimetric Method

In the present study the emphasis was given on two points, one is find out the effective extractants solvent and another is method of determination. Importance also was given on extraction ratio between solvent used as extractants and the amount used or dilution of the sample, shaking time and the incubation period on the basis of which after shaking how much time is required for settle down the solution just before titration/determination. The better result was obtained in 45 minutes to one hour after extraction was completed. Among three extractants, determination of elemental sulfur (ES), acetone can be used as an effective extractant for both S-rich fertilizer and soil sample (% recovery values obtained were 99.0 and 97.0% respectively). On the contrary, the % recoveries with toluene and xylene the values obtained from S-rich fertilizer and S-rich soils were 97.0 and 93.0 and 92.0 and 87.0% respectively. Determination was done with titrimetric method. Colorimetric always time consuming, values obtained with spectrophotometer is sometimes variable and expensive due to using of power supply. In titrimetric method where a high degree of accuracy and precision is not required. It is rapid and suitable for routine analysis in laboratories without using specialized equipment.

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 elemental sulfur in phosphorous pentasulfide by temperature modulated differential scanning calorimetry

Abstract Phosphorous pentasulfide is an important starting material for a number of commercial chemicals. Examples include lubricant additives (Spikes, Trib Lett 17:469–489, 2004), agricultural insecticides (Kirk-Othmer, Enycl Chem Technol 14:549–552, 1995), and mining ore flotation agents. Phosphorous pentasulfide is a mixture of several components, one of which is free elemental sulfur, present at levels of approximately 50 ppm to 20,000 ppm (2 %). The amount of free sulfur present in the phosphorous pentasulfide can impact manufacturing, such as zinc dithiosulfate processing. Therefore, an accurate and fast analytical method to measure elemental sulfur in phosphorous pentasulfide would be of value compared to what is available now.

Determination of Elemental Sulfur in Gasoline by Gas Chromatography with On-Column Injection and Flame Ionization Detection Following Derivatization with Triphenylphosphine

Several years ago, the presence of elemental sulfur in gasoline became a significant issue for the automotive and fuel industries. In several incidents, elemental sulfur at trace levels led to the corrosion of silver alloy fuel sensing elements in automobile gasoline tanks. This report describes a derivatization method that allows the determination of trace levels of elemental sulfur using flame ionization detection. The sample is derivatized with triphenylphosphine to form triphenylphosphine sulfide. This component is readily detected with a flame ionization detector. In most analyses, on-column injection was employed to allow detection of trace levels of elemental sulfur. However some analyses with splitless injection were also performed. For some gasolines, detection limits on the order of less than 1 microg/g elemental sulfur were possible with this approach. However, the detection limit can vary depending upon the concentration of trace higher boiling components. The precision of the analysis, as measured by the relative standard deviation of triplicate injections, for gasolines containing 1 to 10 microg/g of elemental sulfur was in the 1 to 3% range. The recovery of a gasoline spiked with approximately 4 microg/g elemental sulfur was 102%. The presence of ethanol did not appear to affect results.

Determination of Elemental Sulfur in Naphtha and Gasoline by Gas Chromatography/Mass Spectrometry

Trace elemental sulfur, S0, in naphtha and gasoline seriously affects the quality of naphtha and gasoline. It is difficult to analyze the contents of trace elemental sulfur because of their low concentrations. Presently, the S0 contents are usually determined by polarography, but the practical use of this method is limited because of some interference factors. In this work, S0 structure in naphtha and gasoline was studied through many experiments by gas chromatography/mass spectrometry (GC/MS) and S0 is mainly present as S8. A new analytical method for S0 determination in naphtha and gasoline using GC/MS was developed. The S0 was analyzed through selected ion monitoring (SIM) and quantitative determination was achieved through an external standard method. One microliter of sample oil was directly injected and analyzed by GC/MS within 16 min. In comparison with the existing method for S0 determination, this technique was found to be much simpler, faster, more sensitive and interference-free. Good correlation coefficients (> 0.9995) for the S0 calibration curves were obtained in the concentration range of 0.01 mg/L–100 mg/L by using appropriate GC/MS parameters. The absolute limit of detection of this method was 9.55 pg and the precision relative standard deviation (RSD) was usually better than 5% and the recoveries were 93.01–106.21%. The method was used successfully in the determination of S0 in naphtha and gasoline samples collected in Jiujiang Refinery and it had great application prospects. In addition, this technique required only a very small sample size to perform a good analysis, which was an important advantage for studies where sample size was restricted.

Determination of Elemental Sulfur in Explosives and Explosive Residues by Gas Chromatography-Mass Spectrometry

A new method for the positive identification of elemental sulfur in explosives and explosive residues is developed. Following a carbon disulfide wash of explosives or explosive residues, a sample of the extracted material is injected onto a gas chromatography (GC) column, then analyzed via mass-selective (MS) detection. A positive identification of elemental sulfur is based on both retention time and fragmentation pattern. The GC-MS method is demonstrated to be useful in detecting and positively identifying elemental sulfur from both burned and unburned explosive mixtures. With a detection limit of 2.5 ng (2.5 x 10(-9) grams) of elemental sulfur on the column, it is shown to be 400 times more sensitive than the presumptive chemical color test that is currently the method employed for detection of small amounts of sulfur.

Separation and determination of small amounts of sulfur in technical thiophanate‐methyl by reversed‐phase high‐performance liquid chromatography

AbstractA simple and rapid reversed phase high‐performance liquid chromatographic method for separation and determination of elemental sulfur in technical thiophanate‐methyl using a reversed‐phase C18 column and methanol‐water‐tetrahydrofuran (90 : 8 : 2 v/v/v) as eluent with UV detection at 254 nm has been developed and validated with respect to accuracy, precision, specificity, linearity range, and limits of detection and quantification. The method was found to be suitable not only for detection but also determination of elemental sulfur at levels of 5×10–9 g.

Determination of elemental sulfur in coal by gas chromatography-mass spectrometry.

A method for the determination of S0 in coal based on the extraction with cyclohexane with subsequent quantitative analysis of elemental sulfur in the extract by GC/MS is described. The quantity of elemental sulfur was determined in four coal samples with different distribution of sulfur forms. The effect of solvent and extraction time on the efficiency of sulfur removal was studied. The elemental sulfur extracted from coal occurred in the form of S6, S7 and S8. Calibration solutions were prepared from freshly recrystalized elemental sulfur. It was found that the injection temperature has a crucial influence on the m/z 64 ion chromatogram.

Determination of elemental sulfur in bottom sediments using high-performance liquid chromatography

A procedure for determining elemental sulfur in bottom sediments by microcolumn reversed-phase high-performance liquid chromatography was developed. The analytical range was 4–1200 μg/g (in terms of the dry weight of a sediment). The procedure is based on the direct injection of acetone extracts of sediments into a chromatographic column. The detection limit was 5 ng/peak (signal-to-noise ratio of 3 : 1); the relative standard deviation was 5.6%. Errors introduced at particular stages of analysis and the total errors were evaluated for different sampling techniques. The results of determining elemental sulfur in the core samples of bottom sediments from Lake Baikal are presented.

Determination of trace elemental sulfur and hydrogen sulfide in petroleum and its distillates by preliminary extraction with voltammetric detection

Determination of elemental sulfur and hydrogen sulfide at sub-ppm levels in petroleum and its distillates was individually investigated using two convenient, accurate and sensitive procedures. These involved preliminary extraction of sample species, which were then detected by differential pulse polarography (DPP) and square wave voltammetry (SWV) on dropping mercury and static mercury drop electrodes, respectively. In one procedure, the required amount of sample was diluted with isopropyl alcohol–toluene (2 + 1 v/v) and was heated to 80 °C. Hydrogen sulfide available in the sample was then delivered through a designed system to an absorber cell by a controlled flow of helium gas in order for its concentration to be determined by SWV detection. In another procedure, an appropriate amount of sample was shaken with a recommended volume of extraction solution. The mixture was filtered in two steps and was then ready for its elemental sulfur content to be measured by DPP detection. The effects of extraction parameters such as volume ratio of extraction solution to sample, type of extraction solution and extraction time were studied in order to achieve a high recovery of sulfur. Various instrumental factors such as scan rate, pulse height, initial and final potential and purge time were optimized. The method was free from interferences from organic sulfides, disulfides and thiophene. The 3ς detection limits were 10 and 100 ng g−1 for H2S (by use of SWV) and S0 (by use of DPP), respectively. At a 1 μg g−1 level in samples, the relative standard deviations (n = 4) were 1.7 and 3.3% for SWV and DPP, respectively

Semi‐automatic determination of elemental sulphur in rubber

Electro-active elemental sulphur dissolved in hydrazine hydrate solvent was studied by d.c. polarography, cyclic voltammetry and millicoulometry in sodium acetate, ammonium tartrate and sodium phosphate buffers in an aqueous medium. The method, which uses a mercury electrode, is highly sensitive with less interference than other polarographic methods. The method was extended to the determination of sulphur in pressure rubber tubing. This paper also suggests a mechanism of electrode reaction.

Determination of elemental sulfur by size-exclusion chromatography optimization and petrochemical applications

Factors affecting the elution of elemental sulfur beyond the total permeation limit of a size-exclusion chromatographic (SEC) column are investigated. The pore diameter of the column packing is found to be the most important parameter, and optimum results are achieved from a single 10 3 Å pore polystyrene-divinylbenzene column with tetrahydrofuran as solvent. It is shown that both the column temperature and solvent flow-rate have little or no influence on the resolution of sulfur from other sample components. The apparent anomalous elution behavior of sulfur is validated by two independent approaches, and is addressed in terms of electronic interactions between sulfur and the phenyl ring of the polystyrene-divinylbenzene packing. The solubilities of sulfur in typical alkylate, naphtha and reformate samples at room temperature have been determined by the SEC method. The amounts of sulfur in typical hydrotreated cracked naphtha and gas oil samples from pilot unit runs have also been measured. These results are discussed in relation to relative solubilities of sulfur in compounds belonging to different hydrocarbon classes. Specifically, the solubility of sulfur is found to decrease with hydrocarbon type in the order, aromatics>naphthenes>olefins> n-alkanes>isoalkanes.

Quantitative HPTLC Determination of Elemental Sulfur in Sulfur Topical Medications

Abstract A method was developed for determination of elemental sulfur in sulfur topical pharmaceutical preparations involving separation on a preadsorbent HPTLC silica gel plate with fluorescent phosphor, detection by fluorescence quenching, and quantification by densitometric scanning. Sulfur was directly detected and quantified on the plate at levels as low as 800 ng, and no interference was encountered from other ingredients in the medication formulations. The method was applied to the analysis of commercial liquid and cream preparations having respective label values of 5% and 8% sulfur, and recoveries averaged 99.3 and 99.5%. An unknown cream medication was assayed using the method and the accuracy of the result was validated by standard addition. All analyses were carried out with 5 or 6 replicates to evaluate precision, and coefficients of variation ranged from 2–4%.

Quantitative extraction and determination of elemental sulfur and stoichiometric oxidation of sulfide to elemental sulfur by Thiobacillus thiooxidans

A sensitive and quantitative analytical method for determining elemental sulfur in a biological system was developed. Elemental sulfur was determined after extraction with petroleum ether by cyanolysis and ferric thiocyanate color formation in acetone. The method was successfully applied to show that sulfide was oxidized by Thiobacillus thiooxidans to elemental sulfur nearly stoichiometrically when further oxidation of elemental sulfur was inhibited by N-ethylmaleimide.Key words: elemental sulfur, quantitative analysis, sulfide oxidation, Thiobacillus thiooxidans.

Determination of elemental sulphur in coal by supercritical fluid extraction and gas chromatography with atomic emission detection

A rapid and reproducible method to quantify elemental sulphur in coal has been developed using supercritical fluid extraction (s.f.e.) and gas chromatography with atomic emission detection (g.c./a.e.d.). Quantitative spike recoveries of elemental sulphur were obtained from both sand (97 ± 6%) and pre-extracted coal (96 ± 3%). The total amount of elemental sulphur removed was found to be independent of the coal particle size, which indicates that elemental sulphur in coal is located at the surface of the coal particles. North Dakota (Beulah) lignite, Alaska (Beluga) subbituminous coal, and Illinois Basin bituminous coal samples contained elemental sulphur in the range of 2–3500 μg S 8 g − 1 coal. As much as 35.7% of the ‘organic’ sulphur in coal (as determined in accordance with ASTM guidelines) is, in fact, elemental sulphur rather than true organic sulphur. In addition, the elemental sulphur values for the coals used in this study correlate well with the inorganic sulphur fractions of coal but not with ASTM-defined ‘organic’ sulphur.

Determination of elemental sulphur, sulphide and their mixtures in electrolyte solutions by a.c. voltammetry

The electrochemical behaviour of elemental sulphur, sulphide and their mixtures on a mercury electrode in 0.5 mol dm −3 NaCl-NaOH supporting electrolyte at pH 10 with and without the addition of 10% (v/v) methanol and 1 × 10 −5 mol dm −3 toluene was studied. Investigations were carried out over a wide concentration range (from 1 × 10 −8 to 1 × 10 −3 mol dm −3) of sulphur species in solution by a.c. voltammetry. Differences in the electrochemical behaviour during the formation of HgS at the electrode surface were observed between the two investigated species under different experimental conditions such as accumulation at different potential and voltammetric scan directions. Based on these differences, a method for the determination of sulphide, elemental sulphur and their mixtures in the aqueous solution is proposed. The solubility of elemental sulphur in aqueous medium at room temperature was determined as 1.7 × 10 −6 mol dm −3. The usefulness of the proposed method for the direct determination of sulphide and elemental sulphur in natural waters is discussed.

Determination of elemental sulfur, mercaptan and disulfide in petroleum naphtha by differential-pulse polarography

The polarographic behaviour of elemental sulfur, mercaptan and disulfide in 0.032 mol/l sulfuric acid-ethanolnaphtha is described. The peak potentials for elemental sulfur and mercaptan are about 200 mV apart, which allows simultaneous determination of these compounds. The calibration plot is linear up to 1 mg·1−1 for elemental sulfur and it is a curve depending on molecular weight for mercaptan. The disulfide present a peak close to the peak of the mercaptans but with a lower sensitivity and therefore they do not interfere. The polarographic properties, diffusion, reversibility and electrocapillary curves are discussed.

Determination of elemental sulfur in viscose precipitation baths by an extraction-spectrophotometric method

The proposed extraction-photometric procedure for determining elemental sulfur content using dodecanes as the extractant and with purification of the extracts from surface-active substances with aluminum oxide can be used to determine elemental sulfur content in precipitation baths of viscose manufacture within the range from 10 to 60 mg/dm3 or higher, and also for the analysis of precipitation bath sludges.

Gas chromatographic method for the determination of elemental sulphur in sediments

Gas chromatographic method for the determination of elemental sulphur in sediments

An indirect flame emission spectrometry method for the determination of sulphur and sulphur compounds. II

An accurate and simple indirect method of flame-emission spectrometric determination of small quantities of elemental sulphur and many sulphur compounds, without their prior separation, is described. Advantage is taken of the difference in capacity for oxidation of sulphur and sulphur compounds to sulphate. The analytical procedure is validated by determination of elemental sulphur and sodium sulphide. Analysis is based on oxidation of the sulphur compounds in one portion of sample with H2O2 to sulphate, and of sulphur species oxidized to sulphate. From the difference, the amount of elemental sulphur is calculated; the result for the first sample gives the amount of combined sulphur present. The detection limit is 1 ppm of sulphur.