Carbon Disulphide determination

MDHS 14 General method for the gravimetric determination of respirable and total dust MDHS 15 Carbon disulphide MDHS 16 Mercury vapour in air Laboratory method using hopcalite adsorbent tubes, and acid dissolution with cold vapour atomic absorption spectrometric analysis MDHS 17 Benzene in air Laboratory method using charcoal adsorbent tubes, solvent desorption and gas chromatography MDHS 18 Tetra alkyl lead compounds in air Continuous on-site monitoring method using PAC Check atomic absorption spirometry... 

Cadmium and inorganic compounds of cadmium in air (atomic absorption spectrometry). Cadmium and inorganic compounds of cadmium in air (X-ray fluorescence spectroscopy). Chromium and inorganic compounds of chromium in air (atomic absorption spectrometry). Chromium and inorganic compounds of chromium in air (X-ray fluorescence spectroscopy). General methods for the gravimetric determination of respirable and total inhalable dust. Carbon disulphide in air. 

Seaman and Stewart have described a radio-chemical assay for determining neomycin on cotton-fabric. Neomycin is reacted with carbon disulphide forming a dithiocarbonate which is then decomposed with [H°Ag] silver nitrate. The precipitated [H Ag] silver sulphide, which is directly related to the amount of neomycin present, is estimated by counting. 

It is most convenient to determine the spectrum in solutions. Excellent solvents are those that have poor absorptions of their own. These solvents absorbs in one region or the other. Some important solvents are (/) Chloroform (ii) carbon tetrachloride or (iii) carbon disulphide. 

Singhal et al. [78, 79] have described a titrimetric method for the determination of low levels of Oxamyl residues in soils. Their investigations revealed that after hydrolysis Oxamyl gave a brown precipitate with carbon disulphide and an alkaline solution of copper(II) sulphate. This reaction suggested a procedure for the determination of Oxamyl by titration with ethylene diamine tetracetic acid of the copper remaining unreacted to the 1-(2 pyridylazo)-2-naphthol end-point indicator). The following stoichiometric reaction appeared to occur between Oxamyl and the reagents ... 

Determine graphically the theoretical number of plates required for the rectifying and stripping portions of the column, if the reflux ratio = 3, the slope of the fractionating line = 1.4, the purity of the product = 99 per cent and the percentage of carbon disulphide in the waste liquors = 1 per cent. 

Determination of the molecular weight by cryoseopic and ebullioseopic measurements in various solvents, including carbon disulphide, various... 

Sulphur and Iodine.—Various methods have been described for the preparation of compounds of iodine and sulphur,3 but to-day the products are regarded merely as mixtures of the elements.1 In solution in carbon disulphide, iodine and sulphur exist side by side permanently uncombined. The freezing-point curves for mixtures of the two elements,5 as also the vapour pressure curve of the fusion products,6 likewise give no indication whatever of chemical combination, although sulphur forms a solid solution in iodine. A further proof of the absence of combination is the fact that when dissolved in iodine, sulphur has a normal molecular weight, determined eryoseopically, only a little below that required for S8.7 The present condition of our knowledge, therefore, may be summed up in the statement that no definite compound of sulphur and iodine has yet been obtained.8... 

Carbon disulphide vapour appears to be associated to a small extent. When the vapour and ether vapour are mixed at constant volume at 80° C. under atmospheric pressure, the increase of pressure observed indicates previous association of the carbon disulphide to the extent of 0-14 per cent., whilst vapour density determinations by Dumas method give results corresponding with 2 per cent, association.3... 

At very low temperatures carbon disulphide solidifies to a crystalline mass which melts at —112-97° C.7 The crystallisation may be accompanied by the emission of small sparks.8 At —185° C. the crystals are tetragonal.9 The heat of fusion, deduced from determinations of the freezing-points of dilute solutions in certain organic solvents,10 is 660 calories. The fusion curve showing the connection between pressure and melting-point has been determined.11... 

By using excess of iodine and titrating after one hour with sodium thiosulphate in the presence of a little carbon disulphide, the reaction may be used for the determination of the selenocyanate.1... 

Arsenic triiodide is soluble in carbon disulphide, alcohol, ether, chloroform, benzene, toluene and the xylenes.5 The solution in carbon disulphide gradually darkens owing to absorption of oxygen and liberation of iodine.6 With alcohol at 150° C. ethyl iodide is formed. In methylene iodide 5 the triiodide dissolves to the extent of 17-4 parts of AsI3 in 100 parts of solvent at 12° C. The dipole moment in various solvents has been determined.7... 

Fatty Substances and Free Sulphur.—The fats are determined as with tanned leather, carbon disulphide free from sulphur being used for the extraction. If the leather contains free sulphur, this occurs with the fat thus extracted. In such case, when the extracted matter is weighed, it is carefully oxidised in a platinum dish with fuming nitric acid to complete solution the acid is then evaporated off on a water-bath, the residue neutralised with concentrated sodium carbonate solution, the liquid taken to dryness and the residue ignited. This residue is dissolved, in water, the solution acidified with hydrochloric acid, the oxidation completed by boiling with a little bromine water, and the sulphate precipitated with barium chloride. The amount of sulphur corresponding with the... 

Analyses of the purified compound by G. Lemoine, G. Ramme, H. Schulze, J. Mai and F. Schaffer, L. Wolter, and A. Stock and co-workers are in agreement with the formula P4S3. G. Lemoine found that the fractional crystallization and fractional sublimation of the tetritatrisulphide gave no evidence of a heterogeneity. The vap. density determinations of G. Ramme, G. Lemoine, F. Isambert, A. Helff, and A. Stock and H. von Bezold are in agreement with this formula, so also is the mol. wt. calculated from the effect of this sulphide on the b.p. of carbon disulphide by A. Helff, and A. Stock and H. von Bezold. The fused product appears as a... 

The OVM 3500 monitor was applied by Cohen et al. (1989) to determine VOC concentrations in a study of 35 homes in West Virginia, USA. Samplers were placed in the main bedroom at a height of approximately 1.5 m, and outdoors in a specially fabricated aluminum shelter that kept the sampler dry. They were exposed for one 3 week period before analysis by solvent desorption using 1.5 ml carbon disulphide and analysis with GC-FID. Results for indoor concentrations of some of the 17 compounds reported are shown in Table 3.2. 

A nationwide study of indoor air concentrations of 26 VOCs was conducted in Canada in 1991 (Otson, Fellin and Tran, 1994). An OVM-3500 sampler was exposed for 24 h on one occasion in 757 homes. Approximately equal numbers of homes were sampled in each of four seasons. VOCs were extracted with 1.5 ml of carbon disulphide and 26 compounds were determined by GC with a mass selective detector operated in the selected ion monitoring mode. Detection limits were estimated to be in the range 1.6-5.9pg/m3. Mean concentrations of selected compounds are shown in Table 3.2. 

Brinkmann, H. Gas chromatographic determination of sulphur dioxide in presence of carbon disulphide, hydrogen sulphide, carbon dioxide and inert gas. Chem. Tech. 17, 168(1965). -Anal. Abstr. 13, 3387(1966). 

Leek and Bagander [342] determined reduced sulphur compounds (hydrogen sulphide, methyl mercaptan, carbon disulphide and dimethyl sulphide) in seawater by gas chromatography using flame detection. Detection limits ranged from 0.2ng L 1 for carbon disulphide to 0.6ng L 1 for methyl mercaptan. Hydrogen sulphide was determined at the... 

The volume changes on mixing non-aqueous liquids, the densities of mixed liquids, of solutions of non-polar solutes in non-polar solvents, and the changes of total volume on the solution of solid salts in water, noticed at an early period and much investigated, can only be mentioned here some aspects of these will be dealt with later. Hyde found the densities of solutions of jp-nitrotoluene in carbon disulphide smaller than the density of either component, but the anomaly disappears if the p-nitrotoluene is supposed to be in the liquid state. Biron found that the volume change on mixing two liquids was Av=kx( —x where x , (1— ) are the mol fractions, and he investigated the effect of pressure on the value of Av. The apparent specific volume of alcohol in aqueous mixtures was determined by Brown, lo... 

As an example of this behaviour we may take the divariant system composed of a mixture of carbon disulphide and benzene and their vapours. The total masses of the two components in the closed system are given initially. We know from the phase rule that if T and p are fixed the physico-chemical state of the system is determined, that is to say the mole fractions or weight fractions of the components in both liquid and vapour phase are determined. As we have seen these weight fractions are, in general, different. If we know these weight fractions and the initial masses of the components and m% we can calculate the masses of the two phases from the equations... 

Sulphur may be extracted from mixtures by freshly distilled carbon disulphide. It may be determined by evaporating at least three times with strong a ua regia to convert it to sulphuric acid, and precipitating with barium chloride. 

This should be white and as transparent as possible. It should have no taste or smell. It must be free from mechanical impurities and acidity, and must dissolve completely in acetone or carbon disulphide.. On ignition it should give ver> little ash. The melting point is not very definite. It is generally specified for the special purpose for which the paraffin wax is required. The determination of the setting point is sometimes preferred. 

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