High precision determination of titration alkalinity and total carbon dioxide content of sea water by potentiometric titration
TL;DR: In this paper, the titration alkalinity At and the total carbon dioxide concentration Σ CO2 of a sea water sample can be determined by direct potentiometric titration.
About: This article is published in Deep Sea Research and Oceanographic Abstracts.The article was published on 1970-08-01. It has received 323 citations till now. The article focuses on the topics: Gran plot & Potentiometric titration.
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TL;DR: The apparent dissociation constants of carbonic acid in seawater were determined as functions of temperature (2-35°C) and salinity (19-43%) at atmospheric pressure by measurement of K'1 and the product K', K' as discussed by the authors.
Abstract: The apparent dissociation constants of carbonic acid in seawater were determined as functions of temperature (2-35°C) and salinity ( 19-43%) at atmospheric pressure by measurement of K’1 and the product K’, K’,. At 35sa salinity and 25°C the measured values were pE1 = 6.600 and pK’2 = 9.115; at 35% and 2°C the measured values were pK’1 = 6.177 and pKPz = 9.431.
3,085 citations
01 Jun 1981
TL;DR: In this article, a non-linear least squares procedure is proposed to estimate the total alkalinity and total inorganic carbon (CT) of a seawater sample from potentiometric titration data.
Abstract: The total (or titration) alkalinity of a natural water sample can be regarded as a measure of the proton deficit of the solution relative to an arbitrarily defined zero level of protons. The problem of unambiguously incorporating any particular acid-base system into the definition of alkalinity is thus the one of deciding which form to specify as the zero level of protons, and it is proposed that it be defined so that acids with a dissociation constant K > 10−4·5 (at 25°C and zero ionic strength) are considered as proton donors, whilst those bases formed from weak acids with K ⪕ 10−4·5 are cosidered proton acceptors. A non-linear least squares procedure is suggested in order to estimate the total alkalinity (AT) and total inorganic carbon (CT) of a seawater sample from potentiometric titration data. The approach offers a significant conceptual improvement over the currently used refined Gran functions. In addition, an estimate of the statistical uncertainty of the estimated values of AT and CT is available. As it unnecessary to titrate beyond the alkalinity equivalence point, it may also be possible to speed up the titrations.
514 citations
TL;DR: In this paper, the effect of pressure on the apparent constants (K p i K o i ) have been fit to equations of the form ln ( K p i k o i) = − (ΔVP + 0.5 ΔK P 2 )/RT where the volume and compressibility changes are polynomial functions of temperature.
478 citations
TL;DR: In this article, a two-stage, potentiometric, open-cell titration using coulometrically analyzed hydrochloric acid was used to certify reference materials based on seawater for total alkalinity.
461 citations
Cites methods from "High precision determination of tit..."
...Additional development work by Edmond (1970) and by Arnold Bainbridge and the GEOSECS oper- 0304-4203/02/$ - see front matter D 2002 Elsevier Science B.V....
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...An open titration cell is used, in contrast to the closed cells developed by Edmond (1970) or Bradshaw and Brewer (1988), which makes it straightforward to weigh out a known quantity of seawater for analysis....
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TL;DR: Kadar et al. as mentioned in this paper measured the change in alkalinity of three marine phytoplankton species, Phaeodactylum tricornutum, Dunaliella tertiolecta, and Monochrysis lutheri, and reported their mcasurcmcnts of alkalininity changes during the growth of phyto-ankton on both NOaand NI-IJ+ as nitrogen sources.
Abstract: Continuous cultures of three marine phytoplankton species, Phaeodactylum tricornutum, Dunaliella tertiolecta, and Monochrysis lutheri, were monitored for changes in alkalinity of the culture medium resulting From NO, and NHa+ uptake. Uptake of NO,caused an increase in alkalinity, whereas uptake of NH,+ produced a decrease. These results are consistent with the type of schematic equation proposed by Redfield, Ketchum, and Richards for photosynthetic assimilation of inorganic nitrogen, in which NO, uptake is balanced by OHproduction and NHa+ uptake leads to H+ generation. These reactions suggest active uptake of nitrogen species by microbes. We have been unable to demonstrate the exact stoichiometry of this relationship, and the role of P uptake in the alkalinity change is unclear. An offset in the data, functionally equivalent to the production of some strong acid, may be due to reactions on the walls of the vessel, active uptake of cations, or extrusion of H’ ions by the growing cells. An understanding of the oceanic CO2 system is important in many branches of marine chemistry and biolo,gy. Experimentally, this may be approached through measurement of any two of the four variablcs pH, alkalinity, pCOa, and total COz, and from any two of these properties the others can be calculated (Skirrow 1965). Many recent data have been obtained by the potentiometric titration technique ( Dyrsscn 1965; Edmond 1970) that enables the alkalinity and total COz to be measured in a single sample. The alkalinity of scawater is defined as the number of equivalents of strong acid required to titrate 1 liter of seawater to the C02-HC03end point. Analytically, this is equivalent to the sum of the concentrations of the anions of carbonic and other weaker acids. Alkalinity is thus inherently associated with charge balance ( Stumm and Morgan 1970), and the addition or removal of neutral CO2 during respiration or photosynthesis has no cffcct on this property. All this is frequently taken to mean that the photosynthetic or decomposition processes occurring in aquatic environments do not generate alkalinity changes. This is ’ Contribution No. 3595 from the Woods IIole Oceanographic Institution. This research was supported by NSF grants GA-22292 and GX-33295 (P.G.B. ) and ERDA contract AT( 11-l )2532 ( J.C.G. ) . by no means correct. Goldman c t al. (1972) have pointed out that uptake of N03during photosynthesis generates strong base, whereas NH4+ assimilation leads to acid production. Brewer et al. ( 1975) have discussed the reverse effect in which the dccomposition of marine organic matter csscntially leads to the liberation of nitric acid. This strong acid reacts with carbonate ion derived from calcium carbonate dissolution, thus leaving an excess of calcium over that predicted from observed alkalinity changes. These effects have been inferred for many years (Trelease and Trelease 1935; Cramer and Myers 1948; Rcdfield ct al. 1963; Richards 1965; Berner et al. 1970; Gaines and Pilson 1972) and indeed are implicit in the Redficld-Ketchum-Richards phytoplankton equations. Yet, as far as we are aware, these phenomena have not been adequately documented and no cxpcrimental prooE cxis ts. Here, we report our mcasurcmcnts of alkalinity changes during the growth of phytoplankton on both NOaand NI-IJ+ as nitrogen sources. We thank J. M. Edmond and F. Morel for their critical review and R. Smith, S. Kadar, A. Fleer, and R. Carbon for their technical assistance.
420 citations
Cites methods from "High precision determination of tit..."
...Many recent data have been obtained by the potentiometric titration technique ( Dyrsscn 1965; Edmond 1970) that enables the alkalinity and total COz to be measured in a single sample....
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References
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TL;DR: In this article, the potential -volume curve obtained during potentiometric titrations shows only a small potential change at the end-point, and it has been customary to plot a deltaE/deltaV-volume curve and to take the peak of this curve as the equivalent point.
Abstract: When the potential - volume curve obtained during potentiometric titrations shows only a small potential change at the end-point, it has been customary to plot a deltaE/deltaV - volume curve and to take the peak of this curve as the equivalent point. In 1950, the author proposed a method of transforming these curves by a numerical manipulation into straight lines intersecting at the equivalence point. In this article another way of transforming titration curves into straight lines has now been developed. A simple theoretical treatment shows that the method can be applied to titrations involving acids and bases, ionic precipitations, formation of complexes, and oxidation - reduction reactions. To facilitate the use of the method a table has been compiled giving quantities to be calculated and plotted against volume of titrant added. These quantities can be evaluated by simple slide rule calculations and, since straight line relationships hold, end-points can be obtained by simple extrapolation. The practice of the method is applicable to potentiometers calibrated either in millivolts or in pH units, even when titrations other than acid - alkali reactions are in use.
2,757 citations
01 Jan 1964
TL;DR: In this article, a book to wait for in this month is given, and even if you have wanted for long time for releasing this book determination of ph theory and practice; you may not be able to get in some stress.
Abstract: That's it, a book to wait for in this month. Even you have wanted for long time for releasing this book determination of ph theory and practice; you may not be able to get in some stress. Should you go around and seek fro the book until you really get it? Are you sure? Are you that free? This condition will force you to always end up to get a book. But now, we are coming to give you excellent solution.
1,456 citations
TL;DR: A modified technique for the Winkler determination of dissolved oxygen has been used at the Chesapeake Bay Institute for several years as discussed by the authors, which results in increased simplicity and speed and reduction in the errors due to manipulation.
Abstract: A modified technique for the Winkler determination of dissolved oxygen has been used at the Chesapeake Bay Institute for several years. The modifications result in increased simplicity and speed and reduction in the errors due to manipulation. The unusual features of the technique are the elimination of the volumetric transfer of the final iodine solution and the reagent concentrations. The sources of errors in the various techniques for the Winkler method are discussed in detail by Carpenter (1965) and by Carritt ( 1964)) who also reports the results of an intercomparison experiment.
788 citations
TL;DR: In this article, the pH-partial pressure of carbon dioxide combination is used to study the oceanic COz system, where the present-day analytical precision and the normal oceanic variances of the above four parameters are considered.
Abstract: ABsTRAcr By combining two or more of the parameters pH, carbonate alkalinity, total carbon dioxide, and partial pressure of carbon dioxide, six equations can be obtained to express the concentration of carbonic acid that include molecular carbon dioxide, ten equations for bicarbonate ion, and eleven equations for carbonate ion concentrations. When the presentday analytical precision and the normal oceanic variances of the above four parameters are considered, the pH-partial pressure of carbon dioxide combination is the most promising to study the oceanic COz system.
146 citations