Interlaboratory trial validation of an event-specific qualitative polymerase chain reaction-based detection method for genetically modified RT73 rapeseed

The qualitative event-specific polymerase chain reaction detection method of genetically modified (GM) RT73 rapeseed was developed based on the cloned 3' end flanking sequence of RT73 rapeseed integration. The specificity of the method for GM RT73 rapeseed was validated using several different GM rapeseed lines, GM maize lines, GM soybean line, non-GM rapeseed, and other non-GM crops. In this study, the developed method was validated through an interlaboratory study by 12 laboratories from 6 countries. The sensitivity of this method was evaluated using several mixed rapeseed meals with different GM RT73 rapeseed contents from 5.0 to 0.01% prepared by our laboratory. The evaluated results showed that all of the rapeseed endogenous reference high mobility group protein gene (HMG I/Y), figwort mosaic virus 35S (FMV 35S) promoter, and RT73 event-specific fragment could be detected from rapeseed samples at 0.1% (w/w) with a confidence level of more than 95%. All results from the 12 laboratories indicated that the developed method could be considered fit for the detection and identification of GM RT73 rapeseed.     

Determination and fractionation of sulphur in a contaminated dredged sediment

Conversion of sulphur compounds in reduced, contaminated sediments that are brought in upland conditions may largely affect the potential mobility of heavy metal contaminants. We applied selected methods for the determination of total sulphur and sulphur fractions in a contaminated sediment in the reduced state and after gradual drying and oxidation during 1 month. Dry ashing, followed by ion chromatographic detection, was reliable for the determination of total sulphur. Good recoveries were obtained in both reference samples and spiked samples. Total sulphur was 14.5±0.6 g kg⁻¹ relative to dry sediment. Wet chemical methods that involve the determination of acid-volatile, Zn–HCl-reducible, chromium-reducible, acetone-soluble and HI-reducible sulphur were used to estimate specific sulphur forms. Results for acetone-soluble sulphur were to high and not consistent with results for other fractions. Major part of sulphur in the sediment (90%) was inorganic. Sulphides were converted partially to sulphate and to intermediary oxidised sulphur compounds upon oxidation of the sediment. The results suggested that the intermediary oxidised sulphur pool in the reduced sediment (2.5 g kg⁻¹) mainly consisted of pyrite, that was not converted during drying and oxidation. No significant changes in organic sulphur were detected.     

Determination of sulphur and total sulphur dioxide in wines by an ICP-AES method

Sulphur contents of the original sample and the sample free from sulphur dioxide were determined by ICP-AES following nitric acid digestion under high pressure (using PAAR HPA equipment), and the total sulphur content was calculated from the difference between the results obtained. With the aim of preparing a sample free from sulphur dioxide, bound sulphur dioxide was released by sodium hydroxide, then after acidifying by phosphoric acid, boiling was carried out. Relative standard deviations of the results obtained for total sulphur, the sulphur without S(IV) and total sulphur dioxide were lower than 2.5, 3.5 and 5% respectively. Various amounts of sulphur (in the form of Na₂SO₄), added to wine samples, were successfully recovered between 95.5 and 104.9%. Based on comparative analyses performed by a widely accepted classic method, the indirect method developed was found to be adequate for the determination of total sulphur dioxide. The procedure is suitable for serial tests.     

Determination and fractionation of sulphur in a contaminated dredged sediment

Conversion of sulphur compounds in reduced, contaminated sediments that are brought in upland conditions may largely affect the potential mobility of heavy metal contaminants. We applied selected methods for the determination of total sulphur and sulphur fractions in a contaminated sediment in the reduced state and after gradual drying and oxidation during 1 month. Dry ashing, followed by ion chromatographic detection, was reliable for the determination of total sulphur. Good recoveries were obtained in both reference samples and spiked samples. Total sulphur was 14.5±0.6 g kg⁻¹ relative to dry sediment. Wet chemical methods that involve the determination of acid-volatile, Zn–HCl-reducible, chromium-reducible, acetone-soluble and HI-reducible sulphur were used to estimate specific sulphur forms. Results for acetone-soluble sulphur were to high and not consistent with results for other fractions. Major part of sulphur in the sediment (90%) was inorganic. Sulphides were converted partially to sulphate and to intermediary oxidised sulphur compounds upon oxidation of the sediment. The results suggested that the intermediary oxidised sulphur pool in the reduced sediment (2.5 g kg⁻¹) mainly consisted of pyrite, that was not converted during drying and oxidation. No significant changes in organic sulphur were detected.     

The fluorimetric determination of phosphate with thiamine

A method for the microdetermination of sulphur in organic compounds by means of combustion in a flow of oxygen is described. The oxides of sulphur are absorbed and stored on a small silver layer. After completion of the combustion, the oxygen is replaced first by nitrogen and secondly by hydrogen which liberates the sulphur as sulphur dioxide and regenerates the silver layer. The sulphur dioxide can be easily absorbed by dilute hydrogen peroxide and determined by any convenient method.     

Ultrasound enhanced aqueous extraction from rapeseed green biomass for polyphenol and protein valorization

The objective of this study was to investigate the effects of ultrasound-enhanced aqueous extraction on the valorization of polyphenols and proteins from rapeseed green biomass. Two types of biomass were studied: mature rapeseed stems collected around the time of seed harvest, and immature rapeseed stems used as a cover crop. Response Surface Methodology (RSM) was employed for obtaining optimal extraction conditions: ultrasound power of 400 W, treatment time of 50 min, sample length of 0.5 cm and agitation speed of 250 rpm. Compared to mature rapeseed stems, immature rapeseed stems require shorter treatment time (30 vs. 50 min), and exhibit higher extraction yield of polyphenols (100 vs. 86%) and proteins (18 vs. 11%) due to their less fibrous structures. These promising findings are opening doors to a potential market for rapeseed stems as a renewable biomass.     

Precise and accurate determination of high concentrations of sulphur by isotope-dilution thermal-ionization mass-spectrometry

An isotope-dilution thermal-ionization mass-spectrometric procedure has been developed for the accurate and precise determination of sulphur in steels and organic-based materials. The sample and isotopically enriched sulphur spike are dissolved in a sealed tube to prevent loss of sulphur and the sulphur isotopes are measured as AsS⁺ ions, with silica gel as an emitter. This technique has been applied to the determination of sulphur in 13 NBS Standard Reference Materials ranging in concentration from 0.03 to 5% S. The relative uncertainty for a single determination is typically 0.5% (95% confidence interval) and arises primarily from the uncertainty in the spike calibration and from sample inhomogeneity.     

Determination of trace amounts of sulphur in selenium

Determination of trace amounts of sulphur as Methylene Blue after reduction of sulphate to sulphide by hydriodic and hypophosphorous acids in acetic acid solution is applied to the determination of trace amounts of sulphur in selenium after removal of the selenium by evaporation with hydrobromic acid. Samples of 100 mg or less of selenium are chosen if the sulphur content is greater than 5-10 ppm; the time required for the separation is about 1.5 hr; 100 ppm of sulphur has been determined with a coeffident of variation of 5.2%. If the sulphur content is less than 5 ppm, 1-g samples must be taken and the time required is then about 3 hr; 0.4 ppm of sulphur has been determined with a standard deviation of 0.13 ppm. The accuracy of the method seems to be well within the random error.     

Crystallisation of polypropylene matrix in composites filled with wooden parts of rapeseed straw

Nucleation ability of native and modified rapeseed straw during the polypropylene crystallization from the melt was investigated by the DSC method. Composites were made from isotactic polypropylene and lignocellulosic material using extrusion and injection moulding techniques. They were obtained using polypropylenes differing with respect to melt flow rates and different varieties of rapeseed straw. Chemical modification was carried out in two stages: through mercerisation and treatment with acetic acid anhydride. In the course of investigations, it was found that both native and modified rapeseed straw acted as an active nucleant of polypropylene crystallisation characterised by low values of MFR indices. It was found that for polypropylenes with high MFR values, the values of crystallization temperatures and crystallization half-time in composites were identical when compared with non-filled polymers. The investigations demonstrated that there were insignificant differences among composites containing straw from different varieties of rapeseed. The analysis of crystallization temperatures confirmed that rapeseed straw modification failed to change this parameter of the crystallization process. A similar tendency was observed in the case of changes of the half-time crystallization process. Moreover, the analysis of the crystallization temperature and crystallization half-time showed that the presence in composites of lignified rapeseed straw particles played an important role in the crystallization conditions.     

Application of microwave heating to the determination of free, combined and total sulphur in rubber

An atomic absorption spectrometry (AAS) method for the determination of total and combined sulphur in rubber and a catalytic method for the determination of free sulphur in rubber are described. The catalytic method is based on the iodine-azide reaction and is followed by an extraction of free sulphur with benzene, toluene or acetone. The catalytic determination, with the aid of gas chromatography, was performed in N,N-dimethylformamide after expelling the more volatile solvents used in the extraction. The calibration is linear over the range 2 × 10⁻⁶ – 3 × 10⁻⁴ M. Before the determination of total and combined sulphur, the rubber samples were decomposed by microwave assisted heating (5 min, 110 W) in a Teflon closed vessel. After microwave heating the solution was clear and homogenous and all sulphur compounds contained in the rubber were quantitatively oxidized to sulphate. The sulphates were then precipitated as BaSO₄ and an excess of barium was determined by AAS. From the difference in the results of the determinations of total and free sulphur the amount of combined sulphur can be calculated, and from the difference in the determinations of total and combined sulphur the amount of free sulphur can be calculated. In the latter case the catalytic analysis is not needed.     

Verification of certified sulphur values in steel reference materials by isotope-dilution mass spectrometry, and characterization of sulphur present on the solid samples

Sulphur in a number of steel reference materials has been determined by isotope-dilution mass spectrometry, utilizing both open-beaker and sealed-tube dissolution techniques. It is confirmed that the sulphur present in most samples can be completely converted into sulphate by the conventional open-beaker dissolution technique. The results on reference materials are in good agreement with the certified values for BCS samples and the recent or revised certified values for JSS and NBS samples. It is found that the sulphur concentration in the vicinity of the surface of the sample chips is higher than the average and that a significant amount of elemental sulphur is present on most chip samples. The ratio of elemental sulphur to average sulphur content tends to vary in proportion to the manganese content when this is less than 1%.     

型煤中硫的还原热解MS和GC/MS分析(英文)

以煤和生物质为主要原料的商用型煤为研究对象，采用还原热解（AP-TPR）在线质谱（MS）联用，以及离线色谱/质谱（GC/MS）分析法，定性和定量研究了家用型煤释放的含硫化合物。不同组成的型煤表现出各自不同的硫释放特性。对于生物型煤来说，仅检测到少量二烷基硫醚和脂肪硫醇的存在。褐煤型煤检测到种类最多的有机硫化物。在高阶煤制成的型煤中没有检测到氧化态的硫化物，其典型特征是存在一些噻吩类硫化物。     

Determination of the sulphur content of a lunar sample by neutron capture gamma-ray spectrometry

The technique of prompt neutron capture gamma-ray spectroscopy has been used to determine sulphur concentrations in extraterrestrial materials. In particular an effort was made to resolve reported discrepancies in the sulphur assays for the lunar rock sample 70215. While the validity of chemical analysis techniques are often influenced by the chemical form of the sulphur, particularly when in low concentration, the method used here is independent of such effects. The lunar and a bulk Allende meteorite sample were analyzed for sulphur, iron and silicon. The latter material, being well documented, was analyzed in order to verify the techniques of measurement and the subsequent methods of data reduction. Based upon our measurements and the acceptance of the silicon and iron content of the lunar sample the sulphur content was found to be 1741±112 ppm by weight.     

Batch (one- and two-stage) production of biodiesel fuel from rapeseed oil

Biodiesel fuel is an alternative and renewable energy source, which may help to reduce air pollution, as well as our dependence on petroleum for energy. Several processes have already been developed for the production of biodiesel. Alkali-catalyzed transesterification with short-chain alcohols, for example, generates high yields of methyl esters in short reaction times. In this study, we have evaluated the efficacy of batch (one- and two-stage) transesterification of rapeseed oil in the production of rapeseed methyl ester. The conversion of rapeseed oil exhibited similar reaction patterns and yields in 30- and 1-L reaction systems. Approximately 98% of the rapeseed oil was converted at 400 rpm within 20 min, under the following conditions: 1% (w/w) KOH, 1∶10 methanol molar ratio, and at 60°C. In the 30-L, two-stage transesterification process, approx 98.5% of the rapeseed oil was converted at a 1∶4.5 molar ratio and 1% (w/w) KOH at 60°C for 30 min (first reaction condition), and at a 1∶1 molar ratio and 0.2% (w/w) KOH at 60°C for 30 min (second reaction condition).     

Mineralization of some organic sulphur compounds by fusion with molten alkali

The action of molten alkali-metal hydroxides for the destruction of organic matter containing sulphur has been studied. Various procedures were developed which differed mainly in the initial phase of the process, mainly with respect to homogenization of the reaction mixture, but also with regard to addition of an auxiliary oxidant. The technique is not universally applicable to sulphur compounds, but is useful for decomposition of sulphur compounds with m.p. > 150 degrees and containing sulphonate, thiocarbonyl, phenazothionium and thio groups. The sulphur is converted into sulphate, which is then determined as barium sulphate.     

Determination of sulphur content in drill core samples by backscattered beta-particles and gamma-ray absorption

A relatively simple method of sulphur determination in drill cores of calcium carbonate matrix is described. The method is based on the combination of measurements of backscattered beta-particles and transmitted low energy gamma-radiation intensities. The transmitted gamma-radiation measurement corrects the errors of sulphur determination caused by the varying strontium sulphate and silicon dioxide content. The method has been tested on 170 samples. It was estimated that the standard deviation of sulphur determination does not exceed 2.5% of sulphur. The apparatus for routine absorption measurement is also described.     

Thermal hazards of cracker mixture using DSC

DSC studies of cracker mixtures of different compositions of potassium nitrate, sulphur and aluminum have shown some critical characteristics either with the increase or decrease in the composition of the components. Specifically, sulphur composition below 8% showed no exothermic activity. The studies revealed that a minimum of 11% to a maximum of 17% of sulphur is required for good cracking characteristics. The kinetics of decomposition of cracker mixture is carried out employing DSC multiple heating rate kinetic method. Increase in sulphur content decrease the energy of activation facilitating easy ignition of the cracker mixtures. Arrhenius parameters for cracker mixture decomposition are reported in this paper.     

Interactions of tetrathionate with sulphite and sulphide

Tetrathionate is converted into thiosulphate in the presence of sulphite, sulphide and their mixtures. These reactions can be applied to analysis for any of these sulphur compounds by determination of the amount of thiosulphate formed. The chemical interactions may also be involved in the regulation of the oxidative sulphur pathways in micro-organisms and be employed to prepare colloidal sulphur particles.     

Sulphur distribution in the products of waste tire pyrolysis

The aim of the presented work was to investigate the distribution of sulphur in tire pyrolysis products as well as the influence of process parameters (temperature and residence time) on sulphur distribution due to environmental concerns. Among modern methods used for waste tire recycling, pyrolysis is one of the most reasonable alternatives meeting current environmental standards. However, waste tire sulphur content can be a potential drawback for pyrolysis products utilisation as fuels. Sulphur is present in tires in different concentrations, depending on the type and age of the tires. Typical sulphur content in tires is about 1.6 mass %. In this paper, the distribution of sulphur in tire pyrolysis products was investigated. Tire pyrolysis yields three different products: liquid, gaseous, and solid residue composed mostly of carbon black (chars). Temperature and residence time are the two most important parameters affecting the yield and composition of the volatile fraction and they are therefore expected to affect the sulphur content in residues. Pyrolysis experiments were carried out in a laboratory pyrolysis reaction unit in the temperature range of 650°C to 750°C at different residence times: 88.6 s, 80.2 s, and 73.9 s. Liquid and solid products were analysed by elemental analysis and the distribution of total sulphur in tire pyrolysis products was calculated.