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During a calibration cycle, the calibration solution flows into the sample cell. The analyzer adds the
reagents, measures the color of the calibration solution and calculates the slope of the calibration
curve. The analyzer uses the slope to calculate the concentration of samples.
In the ascorbic acid method
prevents the formation of air bubbles on the sample cell walls. The analyzer uses the absorbance of
this solution as the zero reference, which corrects for interference from background turbidity or color,
changes in lamp intensity or optical changes of the sample cell. A molybdate reagent reacts with
orthophosphate to form a heteropoly acid. The ascorbic acid reagent reduces the heteropoly acid to
a blue color. The analyzer measures the intensity of the blue color and calculates the phosphate
concentration.
In the molybdovanadate method
dissolve particulate matter in the sample and prevent the formation of air bubbles on the sample cell
walls. The analyzer uses the absorbance of this solution as the zero reference, which corrects for
interference from background turbidity or color, changes in lamp intensity or optical changes of the
sample cell. A molybdovanadate reagent reacts with orthophosphate to form a
vanadomolybdophosphoric acid complex with yellow color. The analyzer measures the intensity of
the yellow color and calculates the phosphate concentration.
More information is available on the manufacturer's website.
Installation
Multiple hazards. Only qualified personnel must conduct the tasks described in this section of the
document.
Mechanical installation
Risk of injury or death. Make sure that the wall mounting is able to hold 4 times the weight of the
equipment.
Personal injury hazard.
Instruments or components are heavy. Use assistance to install or move.
The object is heavy. Make sure that the instrument is securely attached to a wall, table or floor for a
safe operation.
This instrument is rated for an altitude of 2000 m (6562 ft) maximum. Use of this instrument at an
altitude higher than 2000 m can slightly increase the potential for the electrical insulation to break
down, which can result in an electric shock hazard. The manufacturer recommends that users with
concerns contact technical support.
Install the analyzer indoors, in a non-hazardous environment. Refer to the supplied mounting
documentation.
1
Standard Methods for the Examination of Water and Wastewater, 21st Edition, 2005, Centennial
Edition, APHA, AWWA, WEF, pp 4-153, 4500-P E. Ascorbic Acid Method.
2
Standard Methods for the Examination of Water and Wastewater, 21st Edition, 2005, Centennial
Edition, APHA, AWWA, WEF, pp 4-151, 4500-P C. Vanadomolybdophosphoric Acid Colormetric
Method.
6 English
1
for low concentrations of orthophosphate, the surfactant reagent
2
for high concentrations of orthophosphate, an acid and surfactant
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