Anions in non saline waters - Determination of Anions in Natural and Treated Waters - page 251

2.72 Palmitate
2.72.1 High performance liquid chromatography
The application of this technique is discussed under multianion analysis in section
13.1.1.6.
2.73 Perchlorate
2.73.1 Ion selective electrode
Jain et al. [593] have described a liquid membrane perchlorate selective electrode.
2.73.2 High performance liquid chromatography
The application of this technique is discussed under multianion analysis in section
13.1.1.5.
2.74 Phthalate
2.74.1 Ion chromatography
The application of this technique is discussed under multianion analysis in section 12.2.4.
2.75 Phosphate
Phosphorus in non saline waters can exist in a multiplicity of forms, including ortho-,
pyro-, poly-, meta-, organic, colloidal, and suspended phosphorus. Each of these forms is
capable of being measured either partly or wholly (depending upon the reaction
conditions) as orthophos-phate through hydrolysis and reaction with molybdate.
Strickland and Parsons [594] therefore attempted to define a labile fraction of phosphorus
(soluble reactive phosphorus) as the amount of phosphorus able to pass a 0.45µm
Millipore filter and reacting within 3min with acid molybdate. This fraction is not
equivalent to orthophosphate, nor dissolved inorganic phosphorus, but rather some ill-
defined intermediate.
It becomes evident, therefore, that methods will measure differing proportions of the
total phosphorus depending upon the reaction conditions employed and whether all or
some of the above-mentioned phosphorus-containing fractions are present in any one
sample.
The ability of the phosphate manifold to recover added phosphorus was tested to a
maximum level of 400µg L −1 . The resultant linear response indicates that the method is