Overview
Alyza IQ PO4
8
ba76201d03
05/2020
1.2
Metrological basics
PO4-P
,
PO4
Phosphate
The salts of the phosphoric acid are called phosphates. With simple phosphoric
acid (orthophosphoric acid, H
3
PO
4
) this is orthophosphate (anion PO
4
3-
).
Measuring method
The Alyza IQ PO4 analyzer measures the concentration of orthophosphate in
an aqueous solution with the aid of the vanadate molybdate method (yellow
method).
The reagent contains an aqueous solution of ammonium monovanadate NH
4-
VO
3
and ammonium heptamolybdate (NH
4
)
6
Mo
7
O
24
with an addition of sulfuric
acid H
2
SO
4
. In an acidic environment, the chemical reaction takes place accord-
ing to the following molecular formula:
PO
4
3-
+ 2 VO
3
-
+ 10 MoO
4
2-
+ 20 H
+
→
[PV
2
Mo
10
O
40
]
5-
+ 10 H
2
O
The originally pale yellow reagent will turn a deep yellow. The change of absor-
bance is photometrically measured at a wavelength of 400 nm. From this, the
concentration of orthophosphate is calculated.
Citation forms
Phosphate concentration is quoted in milligrams per liter (mg/l). This value can
either refer to all orthophosphate ions or to the phosphorus atom included in
them. The values can be converted as follows:
1 mg/l P = 3.066 mg/l PO4
1 mg/l PO4 = 0.3261 mg/l P
Concentration values referring to the phosphorus atom are indicated by the ad-
dition PO4-P (citation form).
1.3
Product description
1.3.1 Overview
Application
Analyzers of the Alyza IQ series are designed for online measurements in aque-
ous samples.
Measurement takes place photometrically, at adjustable intervals, including au-
tomatic sampling (sample filtration and sample feed).
Measuring system
Analyzers of the Alyza IQ series are operated as "sensors" in the
Variant
Measurement
Alyza IQ PO4
Orthophosphate measurements
e.g.
Measurements for regulation of precipitant dosing in
waste water treatment plants
Measurements in the final effluents of waste water
treatment plants
Measurements for water body and river monitoring
Summary of Contents for WTW Alyza IQ PO4
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