Lovibond Maxi Direct, Instruction Manual, Page: 165 / 268

163
MaxiDirect_2c 03/2010
prepare Zero
press ZERO
Zero accepted
prepare Test
press TEST
Countdown
2:00
1.1 Methods
13. Place the vial (the blank) in the sample chamber making
sure that the marks are aligned.
14. Press ZERO key.
Wait for a
reaction period of 2 minutes
(Note 7).
After the reaction period is finished the measurement
starts automatically.
15. Remove the vial from the sample chamber.
16. Place the vial (the sample) in the sample chamber
making sure that the marks are aligned.
17. Press
TEST
key.
The result is shown in the display in mg/L PO
4
3-
.
To calculate the actual phosphonate concentration multiply the reading with the corresponding
dilution factor from table 1.
To calculate the active phosphonate concentration multiply the actual phosphonate
concentration using the appropriate factor from table 2.
Notes:
1. Rinse all glassware with 1:1 Hydrochloric acid first and then rinse with deionised water.
Do not use detergents with phosphates.
2. During UV digestion Phosphonates are converted to Ortho-Phosphates.
This step is normally completed in 10 minutes. High organic loaded samples or a weak
lamp can cause incomplete phosphate conversion.
3. UV lamp available on request.
4. While the UV lamp is on UV safety goggles must be worn.
5. For handling of the UV lamp see manufacturer's manual.
Do not touch the surface of the UV lamp. Fingerprints will etch the glass.
Wipe the UV lamp with a soft and clean tissue between measurements.
6. The reagent does not dissolve completely.
7. The given reaction time of 2 minutes refers to a water sample temperature of more than
15°C. At a sample temperature lower than 15 °C a reaction time of 4 minutes is
required.
Tables:
see next page