SPECIFICATIONS
Method : Titration
Range : Not Specific period
Testing time : Not Specific period
Calculations : 10
mL sample size
M-alkalinity as ppm CaCO₃ = (100) x (total mL
of SO226 used)
50 mL
sample size
P-alkalinity as ppm CaCO₃ = (20) x (total mL
of SO226 used)
INTERFERENCES (All Alkalinity)
1. Phosphates, polymer, silica, organic
acids and ammonia may contribute to alkalinity and could cause a sliding
endpoint.
2. High sulfate levels yield turbidity
that can mask the endpoint color.
3. Suspended solids containing fine
particles of CaCO₃ and Mg(OH)₂ can cause a fading endpoint.
4. Free chlorine can interfere by
destroying the indicator. Add 3 drops of CRD-4 (SO120) before adding the
indicator.
The table below lists the recommended sample size for different types of
water. Others sizes may be used depending on the expected alkalinity level.
|
Type
of Water
|
Sample
Size
|
|
Boiler water
|
10 mL
|
|
Open cooling system
|
50 mL
|
|
Others
|
50 mL
|
PROCEDURE
1. Add 5 drops of special M-Indicator
(SO260) to the same sample used to measure the P-alkalinity.
Note: Three drops of Methyl Orange
indicator (SO223) can be substituted for special M-indicator (SO260). The color
change will be from faint orange to salmon pink.
If the sample turns pink, proceed to the next step.
2. Without refilling the buret, add N/50
Sulfuric Acid (SO226) to the casserole in a steady stream of drops while
stirring the sample.
As soon as one drop turns the entire sample salmon pink, IMMEDIATELY
close the valve.
3. Check the buret scale and record the
total number of mL of SO226 that was used (This also includes the amount of
SO226 used to measure the P-alkalinity.)
M Alkalinity
Titration Analytical Procedure
-
Sample
: 10 mL/20 mL/50 mL/100 mL
-
Add
Indicator (460-SO260) three drops,
Swirl to mix (Colour : Blue).
-
Titration
with Titrant (460-SO226) until
colour change from Blue to Red.
-
Sample
water used = 10 mL,
The result (ppm CaCO3) = Titrant used x 100
Sample water used = 20 mL, The result (ppm CaCO3) = Titrant used x 50
Sample water used = 50 mL,
The result (ppm CaCO3) = Titrant used x 20
Sample water used = 100
mL, The result (ppm CaCO3) = Titrant used x 10