Thermo Scientific Orion AquaMate UV-Vis, Руководство пользователя

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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 | 103
ACR095 Phosphate (Ortho) Reaction Tube Test
Phosphomolybdenum/Ascorbic Acid Method
0.06 – 5 mg/l PO
4
1. Load and run the ACR095 method.
2. Open one 16 mm PO4-P Dilution Tube and add 5 ml of sample. Wipe the exterior of the
vial.
3. Place the vial into the holder in the sample chamber and close the chamber door.
4. Press the Measure Blank function key to measure the blank.
5. Open the sample chamber door. Remove the vial from the holder.
6. Add the contents of one Phosphate Rgt. F10 Power Pack straight from the foil into the vial.
Use a funnel to add the reagent.
7. Close the vial tightly with the cap and swirl the vial for 10-15 seconds to mix contents. The
reagent will not completely dissolve. Wipe the exterior of the vial.
8. Wait for a reaction period of 2 minutes.
9. Place the vial into the holder in the sample chamber and close the chamber door.
10. Press the Measure Sample function key to display the result in mg/l ortho-phosphate.
Notes:
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Ortho-phosphate ions react with the reagent to form an intense blue color.
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Phosphate in organic and condensed inorganic forms (meta-, pyro- and polyphosphates)
must be converted to ortho-phosphate ions before analysis. Pretreatment of the sample
with acid and heat provides the conditions for hydrolysis of the condensed inorganic forms.
Organically combined phosphates are converted to ortho-phosphate ions by heating with
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.
• 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.
Interference Interference Level Interference Interference Level
Aluminum greater than 200 mg/l Nickel greater than 300 mg/l
Arsenate at any level Silica (Silicium dioxide) greater than 50 mg/l
Chromium greater than 100 mg/l Silicate greater than 10 mg/l
Copper greater than 10 mg/l Sulfide at any level
Iron greater than 100 mg/l Zinc greater than 80 mg/l