M Alkalinity


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