Microdetermination Of Carbon Research Articles

Simultaneous microdetermination of carbon, hydrogen and lead in organolead compounds

The straight emtpy-tube method of Korshun and Klimova has been successfully extended to the simultaneous microdetermination of carbon, hydrogen and lead in organolead compounds. In all cases, the lead content was calculated from the weight of the plumbous oxide residue left behind in the fused-silica capsule used to hold the sample. Sulphur could also be determined in the same analysis. Satisfactory results were obtained for all compounds with a standard deviation not exceeding 0.1%.

New external reagents for the simultaneous microdetermination of carbon, hydrogen and mercury

Non-conventional, extremely cheap and readily available materials, namely zinc plates, pumice granules or polystyrene foam cubes, have been utilized as new external mercury-retentive agents at room temperature for the simultaneous gravimetric microdetermination of mercury, carbon and hydrogen by the rapid straight empty-tube method of Korshun and Klimova. A standard Pregl absorption tube charged with the reagent is connected between the combustion tube and the water-absorption tube. Satisfactory results are obtained for carbon, hydrogen and mercury, and compare reasonably well with those found by using the traditional silver wool or gold sponge under similar conditions. Sulphur or halogen can also be determined simultaneously, as usual.

Lanthanum nitrate as external absorbent in the microdetermination of carbon and hydrogen in fluoro and perfluoro compounds

Lanthanum nitrate is recommended as a new external absorbent eliminating fluorine interferences at room temperature in the analysis of various fluorinated materials by the Korshun-Klimova method yielding accurate carbon and hydrogen values.

Microdetermination of carbon and hydrogen in organofluorine compounds

A simple method is described for the elimination of the interferences of fluorine in carbon and hydrogen determination of fluorinated organic compounds. Samples are burnt in a rapid flow of oxygen using the cobalto-cobaltic oxide, rapid straight empty tube, rapid empty tube of Belcher-Ingram, and flash combustion methods. The combustion products are passed through Anhydrone, silica gel-thorium nitrate, and soda asbestos absorption tubes, respectively. Carbon and hydrogen are determined gravimetrically. Acceptable results are generally obtained for a wide range of partially and highly fluorinated organic compounds.

Simultaneous microdetermination of carbon, hydrogen, and mercury in organomercury compounds by various combustion methods

Simultaneous microdetermination of carbon, hydrogen, and mercury in organomercury compounds by various combustion methods

Microdetermination of carbon in organic compounds by oxygen flask combustion with atomic absorption spectrophotometric, gravimetric, and titrimetric finishes

A simple and accurate method is presented for the determination of the carbon content of organic compounds by electric oxygen flask combustion. Five results are obtained for one experiment by atomic absorption spectrophotometric, gravimetric, and titrimetric finishes.

鉄鋼中の極微量の炭素の定量における酸素精製法と助燃剤に関する二，三の検討

鉄鋼中の極微量の炭素の定量における酸素精製法と助燃剤に関する二，三の検討

Microdetermination of carbon and hydrogen in organic compounds using flushed-oxygen combustion tube

A rapid method of microanalysis for carbon and hydrogen in organic compounds using an empty combustion tube fused with two nozzles for flushing oxygen and employing reduced copper for the reduction of nitrogen oxide was investigated. A sample was decomposed rapidly in a sample heater for 2 min, and the gasified vapor was transported to the stationary combustion zone heated at 850 °C, where oxygen was flushing from two nozzles, the oxygen flow was then replaced with nitrogen for 3 min until all the combustion products were swept out towards the absorption train. The sample size was suggested to be around 1 mg for this rapid method, using a Mettler UM6, or an electrobalance having equal precision for the sampling.

Coulometric microdetermination of carbon and hydrogen in organic compounds

An apparatus for accurate determination of carbon and hydrogen has been developed, based on a previously described coulometric Karl Fischer method for determination of small amounts of water in solids. Hydrogen and carbon in a sample are oxidized to water and carbon dioxide, respectively. The water is trapped first, and the carbon dioxide is converted into water by lithium hydroxide and determined in a coulometric cell. Then the water from the hydrogen is released and determined in the same cell. An alternative method for the determination of hydrogen alone with very high precision has also been developed. Samples weighing 0.1–5 mg can be analysed and the standard deviations obtained for a complete C, H determination are ±0.17% and ±0.08%, respectively. That for determination of hydrogen alone is ±0.009%.

A new method for the microdetermination of carbon and hydrogen in fluoro and perfluoro compounds

A method is described for the microdetermination of carbon and hydrogen in fluoro and perfluoro compounds. Samples are burned in a rapid flow of oxygen (35 ml/min) using the rapid straight empty tube method. Carbon and hydrogen are determined by gravimetry. Before entering the soda asbestos tube, the combustion products are conducted through a silica gel-hydrochloric acid mixture and then either through acidified silver nitrate solution or through silica gel transfused with silver nitrate. The standard deviation ranges from ±0.03 to 0.38 for carbon and from ±0.04 to 0.25 for hydrogen.

Microdetermination of carbon, hydrogen, nitrogen and oxygen in petroleum compounds with an automatic elemental analyzer

The Perkin-Elmer Elemental Analyzer has been evaluated for the analysis of carbon, hydrogen, nitrogen and oxygen in typical petroleum samples. Comparison of the Elemental Analyzer results were made with carbon and hydrogen analyses by the Pregl method, oxygen by the Unterzaucher method, and nitrogen results from the automated micro Dumas Analyzer. The results obtained by the automated method were found comparable to those obtained by conventional methods. The automated method was found useful for the analysis of nitrogen in petroleum samples ranging from 0.05 to 0.1% N, a borderline level that presents difficulty for conventional methods. Samples of transformer oil containing known amounts of added phenol were analyzed for oxygen at the 0.2 to 1.0% O level.

Automatic coulometric method for the determination of carbon and hydrogen in organic substances

A coulometric method is proposed for the microdetermination of carbon and hydrogen in organic substances.

Simultaneous determination of carbon, hydrogen, and silicon in organosilicon compounds

A simple method is described for the simultaneous microdetermination of carbon, hydrogen, and silicon in organosilicon compounds containing C, H, O, N, Si, and halogen. The method ensures reliable and accurate results.

Microdetermination of carbon, hydrogen, and selenium in organic compounds

1. A method was developed for the simultaneous determination of carbon, hydrogen, and selenium by the pyrolytic decomposition of the substance in an empty tube, with the absorption of selenium oxide by electrolytically deposited silver at 480°. 2. The method is applicable for the analysis of compounds containing, besides selenium, also sulfur or sulfur and halogen. In such cases the amount of selenium, sulfur, and halogen is determined by calculation from the weight increase of the silver.

A method for the microdetermination of carbon and hydrogen with chromatographic completion

A method for the microdetermination of carbon and hydrogen with the chromatographic determination of the products of the oxidation of the substance has been developed. The accuracy of the method is within 0.2%.

Influence of nitrogen oxides on hydrogen values in the microdetermination of carbon and hydrogen, with an external absorbent

By using an external absorbent for removal of nitrogen oxides it is possible to obtain correct hydrogen values if the whole anhydrone filling of the water-absorption tube is heated at 80–90°C during the combustion. Heating is simply done by providing a normal carbon-hydrogen combustion apparatus with a special glass mortar. The effect of the temperature of the anhydrone filling has been studied as well as the effect of the type of compound.

Microdetermination of carbon and hydrogen: Automatic combustion in a dynamic system

An automatic combustion method has been developed for organic and organo-metallic compounds (5–10 mg samples), based on “wide tube” dynamic combustion in a turbulent oxygen atmosphere. Hydrocarbons, carboranes, transition metal carboran complexes, highly fluorinated compounds, silanes, siloxanes and cyclosilazanes, fluoroderivatives of alkyl phosphinic acids, high polymers, etc. have been analysed by it. Silver-plated pumice, magnesium oxide, fibrous asbestos and crushed quartz were used to absorb interfering elements. Advantages over the manual procedure are simplicity of procedure, rapid combustion of difficultly combustible or highly volatile compounds, and better reproducibility of the results. The overall combustion cycle takes 15 min. The standard deviation for hydrogen is 0.01–0.15 % and for carbon is 0.10–0.23 % (carbon content 20–95 %).

Analyzer for the dynamic microdetermination of carbon, hydrogen, nitrogen, sulfur, and oxygen

Analyzer for the dynamic microdetermination of carbon, hydrogen, nitrogen, sulfur, and oxygen

Microdetermination of carbon, hydrogen, and nitrogen by thermal conductivity measurement

A previously described method for the determination of carbon, hydrogen, and nitrogen has been improved with respect to procedure and apparatus. The sample is burned in a measured amount of pure oxygen. Excess oxygen is absorbed on copper. Nitrogen oxides are reduced. Water is absorbed on a calcium chloride-quartz mixture, and carbon dioxide on a layer of molecular sieve 5A. Nitrogen is detected first, and the signal integrated on an integrator with digital read out. Carbon dioxide is then desorbed through heating and is similarly quantitated. Finally, water is desorbed and determined. Alternate peak height methods were evaluated, but were not accurate enough for micro elemental analysis. The necessary conditions for accurate integration are discussed.

A simple method for the microdetermination of carbon and hydrogen using nitrogen as a transport gas

A simple and quick method for the microdetermination of carbon and hydrogen is described. The substance is oxidized by copper oxide and the combustion gases are transported by nitrogen. Nitrogen oxides are removed by reduced copper. Sulphur-containing compounds are combusted over manganese oxide-silver oxide catalyst. With one filling more than 300 analyses can be performed.