Titration total-carbon dioxide

Edmond, J. M. (1970). High precision determination of titration alkalinity and total carbon dioxide concentration of sea water by potentiometric titration. Deep-Sea Res. 17, 737-750. 

Various workers have discussed the determination of total alkalinity and carbonate [ 10-12], and the carbonate bicarbonate ratio [ 12] in seawater. A typical method utilises an autoanalyser. Total alkalinity (T milliequivelents per litre) is found by adding a known (excess) amount of hydrochloric acid and back titrating with sodium hydroxide solution a pH meter records directly and after differentiation is used to indicate the end-point. Total carbon dioxide (C milliequivelents per litre of HCO3 per litre) is determined by mixing the sample with dilute sulfuric acid and segmenting it with carbon dioxide-free air, so that the carbon dioxide in the sample is expelled into the air segments. The air... 

Bradshaw A.L. and Brewer P.G. (1988a) High precision measurements of alkalinity and total carbon dioxide in seawater by potentiometric titration - 1. Presence of unknown protolyte(s) Mar. Chem. 23, 69-86. 

Bradshaw A.L., Brewer P.G., Shafer D.K. and Williams R.T. (1981) Measurements of total carbon dioxide and alkalinity by potentiometric titration in the GEOSECS program. Earth Planet. Sci. Lett. 55, 99-115. 

Bradshaw, A. L., and Brewer, P. G. (1988) High Precision Measurements of Alkalinity and Total Carbon Dioxide in Seawater by Potentiometric Titration, Mar. Chem. 23, 69-86. 

The method preferred in practice for determining the content of "free carbon dioxide", hydrogen carbonate ions and carbonate ipns, and thereby the total carbon dioxide content, is to titrate the water sample acidi-metrically. Carbonic acid is a dibasic acid it dissociates in two stages. The interrelationship which forms the basis of the acidimetric titration... 

It must be pointed out that this method of testing and calculation is only to be regarded as giving general information. It is, however, important to add that if large discrepancies occur between the levels of hydrogen carbonate ions measured by direct titration and by subtracting the free CO2 from the total carbon dioxide, this is in all probability attributable to the presence of other titratable substances. 

There is conjecture about the existence and identity of a moiety secondary to the C-6 carboxylic acid group due to the disparity between carboxyl titration and carbon dioxide generated from oxidized cellulose. While carboxyl titration measures the carboxylic acid content of the oxidized cellulose, the carbon dioxide generated reflects the total carbonyl moieties. The carbon dioxide method results in a higher carbonyl content than is reflected in the carboxyl titration method (Unruh et al., 1947). ... 

Commercial Hquid sodium alumiaates are normally analyzed for total alumiaa and for sodium oxide by titration with ethylene diaminetetraacetic acid [60-00-4] (EDTA) or hydrochloric acid. Further analysis iacludes the determiaation of soluble alumiaa, soluble siHca, total iasoluble material, sodium oxide content, and carbon dioxide. Aluminum and sodium can also be determiaed by emission spectroscopy. The total iasoluble material is determiaed by weighing the ignited residue after extraction of the soluble material with sodium hydroxide. The sodium oxide content is determiaed ia a flame photometer by comparison to proper standards. Carbon dioxide is usually determiaed by the amount evolved, as ia the Underwood method. 

Then V — 2(V— v) corresponds to the hydroxide, 2(V — v) to the carbonate, and V to the total alkali. To obtain satisfactory results by this method the solution titrated must be cold (as near 0 °C as is practicable), and loss of carbon dioxide must be prevented as far as possible by keeping the tip of the burette immersed in the liquid. 

The catalyst compositions were determined by chemical analysis at the Central Service of Chemical Analysis of the CNRS (Lyon) except for the samples Aj and A2 which were analyzed by Ugicarb Morgon. The analytical method for carbon has been described previously.8 The total amount of carbon was obtained from the combustion of the sample with oxygen. Carbon dioxide was then quantitatively detected by a calibrated thermal conductivity cell. For the polymeric carbon content, the sample was attacked by a hot mixture of nitric and hydrofluoric acids which dissolved every component except for the non-combined carbon. Then, this remaining carbon was transformed into C02 which was analyzed with an electrochemical titration cell. 

Total Acidity.—50 or 100 c.c. of the beer, freed from the bulk of the carbon dioxide, are heated for half an hour at 400 to expel the residual gas and are then titrated with N/io-sodium hydroxide, neutral litmus paper or phenolphthalein being used as indicator when phenolphthalein is employed, it is well to add a slight excess of the alkali and then to run in N/10-sulphuric add until the red coloration disappears. When, however, the liquid is too highly coloured to allow accurate observation of the point of neutrality, the procedure is as follows to 20 c.c. of distilled water, previously boiled, are added 10-12 drops of alcoholic phenolphthalein solution and 0 2 c.c. of N/io-sodium hydroxide. The beer is then titrated with the decinormal alkali and, after each addition of the latter, six drops of the liquid are added to one drop of the indicator prepared as above, placed in the depression of a porcelain plate the titration is finished when this indicator is no longer decolorised in this way. The acidity is usually 1 Race Joum. Soc. Chem. Industry, 190S, XXVII, p, 544. 

Total Acidity.—25 c.c. of the wine are shaken to expel any carbon dioxide present (with sparkling wines gentle heating on a water-bath is necessary) and then titrated with N/4-potassium hydroxide, very sensitive dry litmus paper being used as indicator multiplication of the number of c.c. of alkali used by 0750 (or 0-49) gives the total acidity as grams of tartaric (sulphuric) acid per litre of the wine. 

The air is completely expelled from the apparatus by means of a current of carbon dioxide passed through the drawn-out tube and 50 c.c. of the standard iodine solution introduced into the absorption tube. Through the tapped funnel 100 c.c. of the wine and 2 c.c. of concentrated hydrochloric acid are poured into the flask, which is then carefully heated until half the wine has distilled over, the current of carbon dioxide being maintained meanwhile. The iodine solution, which should still be brown, and the rinsings of the absorption tube are titrated in a beaker with the thiosulphate solution in presence of starch paste. The number of c.c. of iodine solution reduced, multiplied by 0 016, gives the total sulphurous add per litre of the wine. 

Another satisfactory process for the determination of total hardness, based on a somewhat similar principle, is due to Blacher.4 The water is first titrated with decmormal hydrochloric acid until it is neutral to methyl orange, as in the method described above for temporary hardness. After the removal of the carbon dioxide by a current of air, the methyl orange is bleached by the addition of a drop of bromine water a little phenolphthalein and a few drops of alcoholic potassium hydroxide are added, the liquid is just decolorised with dccinormal hydrochloric acid and is then titrated with an alcoholic decmormal solution of potassium palmitate until a decided red colour is produced. The quantity of the potassium palmitate solution required is proportional to the total hardness. 

Titratable Acidity (as Lactic Acid) Accurately weigh a portion of the finely ground dry sample or liquid equivalent to 10.0 g of total solids based on the value obtained under Loss on Drying (above), and transfer into a 500-mL conical flask. Add 100 mL of carbon dioxide-free water, and stir for 1 min. Allow to stand for 1 h at room temperature. Add 0.5 mL of phenolphthalein TS, and titrate with 0.1 A sodium hydroxide to a pink endpoint that persists for 30 s. Each milliliter of 0.1 A sodium hydroxide is equivalent to 9.008 mg of lactic acid. 

Permanent hardness may be determined in the following manner. A quantity of the water measuring 100 ml is boiled gently for 45 minutes, cooled, and made up to its original volume with cold carbon-dioxide-free water. After mixing well, the precipitated temporary hardness is removed by filtration, and the permanent hardness determined in the filtrate by titration with soap solution. The temporary hardness will be the difference between the total and the permanent hardnesses. 

The measurement of total organic carbon (TOC) is the best means of assessing the organic content of a water sample [20]. Organic carbon is oxidized to carbon dioxide (CO,) by heat and oxygen, ultraviolet irradiation, chemical oxidants, or by various combinations of these. The CO, may be measured directly by a non-dispersive infrared analyser or it may be reduced to methane and measured by a flame ionization detector in a gas chromatograph or in a TOC analyser thus equipped. The CO2 may also be titrated chemically. 

Titrations are for total alkalinity and carbon dioxide acidity. 

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