Chemistry Reference
In-Depth Information
Chapter 3
Anions in seawater
3.1
Acetate
3.1.1
Ion chromatography
The application of this technique is discussed in section 12.3.1.
3.2
Acrylate
3.2.1
Ion chromatography
The application of this technique is discussed in section 12.3.1.
3.3
Alkalinity
3.3.1
Titration method
Among the possible analytical methods for alkalinity determination, Gran-type
potentiometric titration [1] combined with a curve-fitting algorithm is considered a
suitable method in seawaters because it does not require
a priori
knowledge of
thermodynamic parameters such as activity coefficients and dissociation constants which
must be known when other analytical methods for alkalinity determination are applied
[2-5].
Alkalinity determination in hypersaline solutions by the Gran-type titration is subject
to a number of errors which can usually be neglected in lower ionic strength solutions.
For example, the pH readings along the titration path may be inaccurate due to the
marked difference between the ionic strength and composition of the sample and the
standard buffers used to calibrate the glass and reference electrode pair [6].
Ben Yaakov and Lorch [7] identified the possible error sources encountered during an
alkalinity determination in brines by a Gran-type titration and analysed the possible
effects of these errors on the accuracy of the measured alkalinity. Special attention was
paid to errors due to possible non-ideal behaviour of the glass-reference electrode pair in
brine. The conclusions of the theoretical error analysis were then used to develop a
titration procedure and an associated algorithm which may simplify alkalinity
determination in highly saline solutions by overcoming problems due to non-ideal
behaviour and instability of commercial pH electrodes.
The titration procedure used was that described by Ben Yaakov
et al.
[8] in which
Search WWH ::
Custom Search