Lovibond MD 110 Manual De Instrucciones página 64

Methods
GB
Interference removal and Pre-Concentration
Cartridge Preparation
1. Remove the plunger of the 20 ml syringe from the barrel and attach the C18 cartridge.
2. Add 5 ml of KS336 (Propan-2-ol) to the syringe barrel, attach the plunger and pass drop-
wise through the cartridge. Discard the eluent to waste.
3. Remove plunger and fill the syringe barrel with 20 ml of deionised/tap water. Attach
the plunger and pass dropwise through the cartridge. Discard the eluent to waste. The
cartridge is now ready to be used/reused.
Interference removal
1. Transfer exactly 20 ml of sample water to a 100 ml sample bottle and dilute to approxi-
mately 50-60 ml with deionised water or tap water.
2. Add drops of KS173 (2,4 Dinitrophenol) until a pale yellow colour is observed in the
sample.
3. Add drops of KS183 (Nitric Acid) until the yellow colour JUST disappears.
4. Remove the plunger from the barrel of the 60ml plastic syringe and firmly attach the
prepared C18 cartridge (see: Cartridge Preparation) to the end of the barrel.
5. Transfer the 50-60 ml of sample from the bottle to the syringe barrel and attach the
plunger. Depress the plunger and allow the sample to flow dropwise from the cartridge.
Do not use excessive force to elute the sample quickly. LEAVE THE C18 CARTRIDGE
ATTACHED and remove the plunger. Discard all of eluted sample to waste.
6. Using the 20 ml syringe, add exactly 20 ml of deionised/tap water to the 60 ml syringe
barrel attached to the cartridge followed by 1 ml (25 drops) of KS255 (Polyacrylate Rea-
gent 1). Gently swirl the syringe to mix.
7. Attach the plunger and depress. Collect the eluted sample in a clean vessel. Allow the
sample to flow dropwise from the cartridge. Do not use excessive force to elute the
sample quickly.
8. Add 10 ml of the eluted water sample into clean vial (24 mm Ø).
9. Using this vial perform the measurement of the method polyacrylate (see page 62).
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