Determination Of Total Carbon Dioxide Research Articles

Effect of selected calculation routines and dissociation constants on the determination of total carbon dioxide in seawater

During the 1989 and 1990 JGOFS North Atlantic Pilot Study a comparison was made between the Coulometric and the acid titration method for determination of total carbon dioxide (TCO 2) in seawater. TCO 2 and alkalinity have been calculated from acid titration using either the modified Gran plot or the curve-fitting routine. Depth profiles showed fair agreement (on average 0.6% or about 12.5 μmol 1 −1) between the TCO 2 calculated from the acid titration method and the TCO 2 measured independently by Coulometry. It is shown that different data processing routines combined with the proper use of dissociation constants can influence the acid titration result considerably. There appears to be a slight offset between calculated and Coulometric data which is smallest when using the combined dissociation constants of Hansson ( Deep-Sea Research, 20, 461–478, 1973) with Goyet and Poisson ( Deep-Sea Research, 36, 1635–1654, 1989). No statistically significant difference could be found between the two used calculation methods (Gran plot and curve-fitting). The agreement between the independent methods of Coulometry and acid titration is encouraging and furthermore independent of depth, for this dataset there is no reason for invoking the existence of interfering (organic) protolytes.

Determination of total carbon dioxide in seawater by capillary type isotachophoresis

A new analytical procedure for total carbon dioxide in seawater was developed: a capillary-type isotachophoresis which applied a tubular microporous PTFE membrane as a preliminary enrichment was used. Carbon dioxide was generated by adding sulfuric acid to seawater samples, permeated through a tubular microporous PTFE membrane and dissolved in sodium hydroxide solution for the separation from large amounts of coexisting anions, such as chloride and sulfate ions. A linear working curve was obtained for artificial seawater samples containing up to 40 mg/l of total carbon dioxide. The proposed method was applied to the determination of total carbon dioxide in surface and bottom seawater samples. Concentrations of the total of free carbon dioxide and carbonic acid, hydrogencarbonate and carbonate ions in these samples were calculated from the concentration of total carbon dioxide, temperature, pH and salinity of samples measured in situ.

Ion-selective membrane electrode for rapid automated determinations of total carbon dioxide.

Previously described ion-selective membrane electrodes useful for determination of total carbon dioxide in biological fluids in automated analyzers show interference from several sources--e.g., fatty acids, keto acids, salicylate, heparin. Judicious selection of membrane components has produced a membrane with superior performance characteristics: short conditioning time, long lifetime in storage, rapid and stable response, low drift, and significantly less susceptibility to interference than other electrodes thus far reported. Samples can be analyzed at 240 samples or more per hour and results correlate well with those by, e.g., the Technicon SMAC II method for total carbon dioxide. Mounted on the Technicon RA-1000, the carbon dioxide sensor is arranged in tandem with sodium and potassium ion-selective electrodes. When all three species are measured in the same buffered sample stream, the sampling rate thus becomes 720 tests per hour, done on 25-microL samples.

A bedside micromethod for the determination of total carbon dioxide in biological fluids.

The quality control of bicarbonate hemodialysis requires the determination of TCO2, either in blood or in dialysate. The use of the M + D TCO2 kit, a bedside micromethod, gave the authors an economical and reliable solution to this problem.

An extremely simple and fast microlitre method for the determination of total carbon dioxide in biological samples.

For those clinical laboratories equipped with a microprocessor-controlled gas analyser, an extremely simple method is described for the determination of the total carbon dioxide content in various biological fluids. Since this method needs only 20 microL of blood plasma or is less dependent on the original total carbon dioxide content, it is especially suited for paediatric purposes. With our procedure the time necessary for one determination equals the time for one capillary blood gas analysis.

Precise and Accurate Determination by Infrared Photometry of C02 Dynamics in Marine Ecosystems

Preliminary studies with an ampule analyzing unit and infrared (IR) detector showed that procedures for standardization and determination of total carbon dioxide (ZCO,), while often precise, lacked the accuracy required to estimate the net productivity and respiration of aquatic ecosystems during studies in which sampling over diel cycles was used. Scaling down sample and standard volumes to the ~l range and the use of a commercial sodium carbonate standard without dilution before and after replicate sample injections gave accurate results as shown by comparison with indirect (pHalkalinity) ZC0 , determinations with a standard error of ? 3 pmoles in the laboratory and 2 6 pmoles at sea for 8 to 10 replicates. This was sufficient to detect a diurnal consumption and nocturnal production of CO, which were inversely correlated w ~ t h O2 variation in a salt marsh, an estuarine mesocosm, and the Canbbean Sea.

Measurement of carbon dioxide in blood.

The remarkable combination of physical and chemical properties displayed by carbon dioxide has enabled the development of a very wide variety of analytical methods for its measurement in blood or blood plasma. Both for historical and technical reasons, the gasometric method of Van Slyke and Neill is preeminent, but great skill is needed to realize its full precision and accuracy. The microgasometer of Natelson, however, has served the clinical laboratory well as a practicable manual means of microanalysis for total carbon dioxide. So far as automated analysis is concerned, it is highly significant that one of the first applications of Skegg's continuous flow principle was to the titrimetric determination of total carbon dioxide in serum; the AutoAnalyzer technique remains the most widely used of its kind, in spite of inherent difficulties in specimen handling, instrumental standardization, and quality control. At the same time, it has been pointed out that the routine determination of total carbon dioxide in serum does not offer a useful screening procedure for identifying or characterizing patients with acid-base disorders; full assessment of acid-base status, including pCO2 in selected patients is much more rewarding. The credit for bringing pCO2 measurements within the scope of the clinical laboratory, by means of the interpolation technique, is largely due to Astrup and his colleagues. Nevertheless, continual improvements have been made in the design and performance of the Severinghaus type of pCO2 electrode, so that reliable instruments offering direct readout of blood pCO2 are available from several manufacturers. The more elaborate versions of these instruments are rugged and work-simplified, and they offer automated self-calibration and end-point detection for pH and pO2, as well as pCO2. It will be surprising if such instruments do not come into widespread use.

Pretreatment apparatus for determination of total carbon dioxide in sea water and in decarbonated sea water

Pretreatment apparatus for determination of total carbon dioxide in sea water and in decarbonated sea water

Rapid method for determination of total carbon dioxide in small blood samples.

Rapid method for determination of total carbon dioxide in small blood samples.

Determination of total carbon dioxide in blood and plasma by means of the cediometer. Theory and experimental verification

The cediometer, an instrument for the determination of total carbon dioxide in blood and plasma samples, consists of a closed system incorporating an electrode chamber filled with a NaHCO 3 solution, a sample chamber in which the CO 2 of injected blood or plasma is set free with an acid reagent and a roller pump which circulates the CO 2-containing gas until the P CO 2 , has become uniform throughout the system and a stable pH in the electrode chamber solution has been reached. The relationship between this pH and the total carbon dioxide content of the sample has been formulated exactly. For an arbitrarily chosen standard system with constant volumes of the three parts of the circuit, constant volume of the sample injected and constant temperature as well as constant pre-injection pH of the electrode chamber solution, the relationship of final pH and total carbon dioxide of the samples was calculated and presented in a table. This table can be used with any cediometer to convert the final pH into total carbon dioxide content. A simple calibration procedure using Na 2CO 3 reference solutions can be used. The method is accurate within ± 1%, when the volumes of the various parts of the circuit do not differ by more than 10% from those of the standard system. The apparatus needs no special care and performs well under ordinary clinical conditions.

Comparison of Gas Chromatographic Method and pH-Alkalinity Method for Determination of Total Carbon Dioxide in Sea Water.

Comparison of Gas Chromatographic Method and pH-Alkalinity Method for Determination of Total Carbon Dioxide in Sea Water.

The Determination of Total Carbon Dioxide in Water

ABSTRACT The method described involves extraction of the dissolved gas from an acidified sample in a modified van Slyke apparatus, and measurement of the electrical. resistance of a standard sodium hydroxide solution before and after equilibration with the extracted gas. The original sample must be not less than about 30 ml. for which a 10 ml., sample is drawn into the extraction apparatus. There is a linear relation between the resistance finally measured and the total carbon dioxide content of the original sample up to a maximum determined by the strength of the standard hydroxide solution, which is thus adjusted to the desired range of carbon dioxide concentration, e.g. 0 ·005 N-NaOH for 0 –50 mg./L and 0 ·02 N for 0 –200 mg./l. CO2. The method is easily sensitive to 0 ·3 mg./l. in the range 0 –50 mg./l. total carbon dioxide and about 1 mg./l. in the range 0 –200 mg./l. With a rigidly standardized procedure increased accuracy was obtained so that replicate determinations, on standard solutions in the 0 –50 mg./l. range did not differ by more than 0 ·16 mg./l. Precautions for handling samples containing carbon dioxide in solution prior to determination have been suggested. About 15 –20 min. are required for each determination and to Mrs D. E..

Determination of Total Carbon Dioxide in Baking Powder

Determination of Total Carbon Dioxide in Baking Powder