Alkalinity is a total concentration of alkaline elements contained in water and commonly expressed in mg / liter or the equivalent of calcium carbonate (CaCO3). It is said that the alkalinity in freshwater very important role because alkalinity is not only a direct effect on the growth of plankton, but also affects other parameters. Alkalinity is the capacity of water to neutralize the acid without any additional impairment pH of the solution.
Alkanitas is the result of reactions in solution so that an analysis of “macro” which incorporates some of the reactions. Alkalinity in the water caused by ions of carbonate, bicarbonate, hydroxide (OH-) and also borates, phosphates, silicates and so forth. In nature water alkalinity largely due to the presence of bicarbonate and the remainder by carbonate and hydroxide (OH-)
Alkalinity is a buffer capacity (buffer capacity) to pH waters consisting of anions such as bicarbonate anions (HCO3-), carbonate (CO32-) and hydroxide (OH-).
Borat (H2BO3-), silicate (HSiO3-), phosphate (HPO42- and H2PO4-) sulfide (HS) and ammonia (NH3) in the water that can neutralize hydrogen cations. But the main thing is alkalnitas forming bicarbonate, carbonate and hydroxide. Alkalinity measurements can be done with the titration method
Tools:
a) a plastic tube
b) Erlenmeyer
c) Pipette
Ingredients:
a) Indicator PP pH 4.5
b) Brom Cressol Red pH 8.3
c) Sulfuric Acid
How it works:
a. Insert the sample into a plastic bottle and then poured into the erlenmeyer.
b. Add 1 drop indicator PP, if not colored PP = 0 (straight to the point. 4).
c. If pink, tembahkan sulfuric acid drop by drop until the color is lost (count the number of drops used) (A ml)
d. Add 3-4 drops of Brom cressol Red plainly titration with sulfuric acid until the color changes from turquoise to pink. (B ml)
e. Record the number of drops of sulfuric acid used.
Calculation:
1 drop of sulfuric acid = 1 ppm
Pp carbonate alkalinity (ppm CaCO3) = A x N titrant x 100/2 x 1000 ml sample
Total alkalinity (ppm CaCO3) = (A + B) x N titrant x 100/2 x 1000 ml sample