Chlorinity determination

The side-chain chlorine contents of benzyl chloride, benzal chloride, and benzotrichlorides are determined by hydrolysis with methanolic sodium hydroxide followed by titration with silver nitrate. Total chlorine determination, including ring chlorine, is made by standard combustion methods (55). Several procedures for the gas chromatographic analysis of chlorotoluene mixtures have been described (56,57). Proton and nuclear magnetic resonance shifts, characteristic iafrared absorption bands, and principal mass spectral peaks have been summarized including sources of reference spectra (58). Procedures for measuring trace benzyl chloride ia air (59) and ia water (60) have been described. 

The demand for the determination proved so great that the method has been placed on a routine basis. One man can make 40 to 50 chlorine determinations on dry resins in an 8-hour day with a precision approaching that of the almost prohibitively time-consuming potassium fusion method. The Parr-bomb method permits about 40 analyses by two men in an 8-hour day, but precision suffers considerably when the work is done at this speed. 

Chlorine, determination by x-ray emission spectrography, 328 in chlorinated hydrocarbon polymers, determination by x-ray absorptiometry, 79-82... 

The methods of analysis for the chlorinated hydrocarbons may be divided into five classes—determination of total organic chlorine, determination of hydrolyzable or labile chlorine, colorimetric methods, physical methods, and bioassays. The last mentioned is beyond the scope of this manuscript and is not considered. 

In one procedure that has been widely used, the sample, after suitable treatment, is refluxed with sodium and isopropyl alcohol, after which the solution is diluted with water and the inorganic chloride is determined by standard methods (13, 54) The method has been adopted by the Association of Official Agricultural Chemists 29, 30) as a tentative one for technical DDT and for dusts, oil solutions, and aqueous emulsions of DDT, for use in the absence of other chlorine-containing compounds. The National Association of Insecticide and Disinfectant Manufacturers has also accepted the total-chlorine method for the analysis of these preparations 28). Essentially the same procedures have been described by Donovan 22), of the Insecticide Division of the Production and Marketing Administration, for technical DDT and various commercial DDT products containing no other compounds interfering with the chlorine determination. 

The metabolic fate of chlordan was studied in rabbits by analysis of the relative chlorine content of chlordan added to normal rabbit s urine and of the chlorine content of the urinary excretory product. The method of analysis was similar to the one previously used (, 4) In addition, hydrolysis of chlordan and of the urinary excretory products was carried out by adding solid sodium hydroxide to saturation to a 10-ml. solution of these substances in hot absolute ethyl alcohol. The mixture was refluxed for 3 hours in a round-bottomed flask immersed in boiling water and the amount of inorganic chlorine determined. Hydrolysis was similarly carried out with solutions of the respective substances in aqueous sodium hydroxide. 

BHC in each technical BHC sample determined by partition chromatography. b The common name for the 7-isomer of benzene hexachloride of a purity of not less than 99%. c Calculated from total chlorine determination on DDT fraction. 

Organic-Chlorine Determinations as a Measure of Insecticide Residues in Agricultural Products... 

Because the results obtained reflect the presence, not only of the insecticide in question, but also of any of its decomposition products or other organic compounds containing halogen, confirmatory evidence of the identity and amount of the residues was desired, Therefore, studies to correlate the results of organic-chlorine determinations with insecticidal activity were undertaken. 

Portions of the treated hay were extracted with benzene, and aliquots of the benzene solution were evaporated to dryness on the steam bath, with a gentle air current to remove the last traces of solvent. The residues were then taken up in deodorized kerosene and tested against houseflies by the turntable method. For comparison, extracts were made up to contain the same amounts of technical toxaphene as were indicated by the chlorine determinations to be present in the treated hay. 

CARTER, NELSON, AND GERSDORFF—ORGANIC-CHLORINE DETERMINATIONS... 

The tests reported in this paper were intended only to show general agreement between the insecticide level calculated from organic-chlorine determinations and fly mortality. 

In the sodium borate solution containing bromide, when the pH 4 buffer is added before the potassium iodate solution, titrations give low total residual chlorine concentrations. This loss increases with the amount of stirring time between the addition of the reagents. Even for a stirring time of 10 seconds, there is a loss of about 17% of the total residual chlorine. If the solution were stirred for 30 min, 85% of the chlorine would have disappeared. The concentration of total residual chlorine determined by the reference methods does not change throughout the experiment. This implies that this loss of chlorine does not occur in the reaction vessel, but in the titration cell as a result of the analytical procedure. 

Now perform that calculation in the opposite direction. Beginning with the known atomic weight of natural chlorine, determine the abundance of the two isotopes ... 

Water quality scouting measurements (conductivity, headspace gas analysis, emulsion index, pH, and chlorine determination)... 

Determination of the Chlorides.—50 c.c. of the wine, rendered faintly alkaline with caustic soda solution,1 are evaporated to dryness in a platinum dish and the residue carefully incinerated as described on p. 190. The ash is extracted with hot water acidified with nitric acid and the chlorine determined in the solution obtained, which should be distinctly acid ... 

Chlorine.—1 gram of the substance is fused with nitre and sodium carbonate, the mass being dissolved in water, the solution acidified with nitric acid, and the chlorine determined either gravimetrically as silver chloride or volumetrically by Volhard s method. 

Chlorine.—In a platinum dish 3-5 grams of the leather are evaporated to dryness with 25 c.c. of pure 10% sodium carbonate solution, the residue being incinerated and taken up in water the solution is neutralised with nitric acid and the chlorine determined by the ordinary gravimetric or volumetric method. 

Chlorine, determination of, in chlorine(I) oxide in carbon tetrachloride and hypochlorous acid solutions, 5 162, 164 Chlorine(I) compounds, 5 156 Chlorine(I) oxide, 5 156 in carbon tetrachloride solution, 5 158, 159 analysis of, 5 162 Chlorine(IV) oxide, 4 152 admixed with inert gas and chlorine, 4 153... 

CoO Co 100-000 78-613 whence Co - 58-812 In 1893-1894, Winkler 2 published the results of his experiments on the atomic weight of cobalt. First, pure cobalt was converted into the neutral chloride, and in six experiments the chlorine determined gravimetrieally as silver chloride ... 

A 60.00-g sample of a dry-cleaning fluid was analyzed and found to contain 10.80 g carbon, 1.36 g hydrogen, and 47.84 g chlorine. Determine the empirical formula of the compound using a table of atomic masses. 

For the determination of chlorine, the mixture is first heated to 115 at 30 mm. pressure. This removes any water and dichlorhydrin. About 5 g. is weighed out and boiled for fifteen minutes with 10 c.c. of a 15 per cent, solution of sodium hydroxide in alcohol. The alcohol is evaporated off and a little water is added. This is boiled for a few minutes and the liquid is acidified with nitric acid and the chlorine determined. The value is somewhat too high owing to the presence of small quantities of dichlorhydrin. 

Elemental analysis of duplicate samples of econazole nitrate was performed using a Perkin-Elmer 2400 CBN analyser. Approximately 3-mg quantities of material were combusted and measured against an acetanilide standard. The chlorine determination was based on oxygen flask combustion followed by titration against mercuric perchlorate which had been standardized against sodium chloride and chlorobenzoic acid. The oxygen content of the samples was calculated by difference. 

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