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Chapter 5
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Orion AQUAfast Reagent Chemistry Instructions for Orion AquaMate
Thermo Scientific
Orion AquaMate Spectrophotometer User Manual
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105
acid and persulfate. The amount of organically combined phosphates can be calculated:
mg/l phosphate (organic) = mg/l phosphate (total) - mg/l phosphate (acid hydrolysable)
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Application: for water, wastewater and seawater.
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Highly buffered samples or samples with extreme pH values should be adjusted between
pH 2 and pH 10 before analysis with 1 mol/l hydrochloric acid or 1 mol/l sodium hydroxide.
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Phosphate, ortho = Phosphorus, reactive
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Interferences: Large amounts of turbidity may cause inconsistent results.
Interfering Substance
Interference Level
Aluminum
greater than 200 mg/l
Arsenate
at any level
Chromium
greater than 100 mg/l
Copper
greater than 10 mg/l
Iron
greater than 100 mg/l
Nickel
greater than 300 mg/l
Silica (Silicium dioxide)
greater than 50 mg/l
Silicate
greater than 10 mg/l
Sulfide
at any level
Zinc
greater than 80 mg/l
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Conversions: mg/l PO
4
= mg/l P x 3.07
mg/l P
2
O
5
= mg/l P x 2.29