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HY DROX IDE, PHENOLPHTHALEIN
& TO TAL AL KA LIN ITY TEST KIT
MODEL WAT -MPH-DR · CODE 7341-DR
QUANTITY CONTENTS CODE
100 BCG-MR Indicator Tablets T-2311-J
100 Phenolphthalein Tablets T-2246-J
30 mL *Barium Chloride Solution, 10% *6117-G
2 x 60 mL *Alkalinity Titration Reagent *6102DR-H
1 Test Tube, 5-10-15 mL, glass, w/cap 0778
1 Direct Reading Titrator, 0-200 Range 0382
*WARNING: Reagents marked with a * are considered hazardous
substances. Material Safety Data Sheets (MSDS) are supplied for these
reagents. For your safety read label and accompanying MSDS before using.
To order individual reagents or test kit components, use the specified code
number.
Carefully read the LaMotte Direct Reading Titrator Instruction Manual
before performing the titrations. The Titrator is calibrated to read the
Alkalinity test result directly in parts per million (ppm) Calcium
Carbonate (CaCO3). Each minor division on the scale equals 4 ppm.
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HY DROX IDE AL KA LIN ITY PRO CE DURE
This test measures the Hydroxide Alkalinity (Hydrate) of water by
titration of the hydroxyl content following the elimination of any
Carbonate Alkalinity interference by precipitation as BaCO3.
1. Fill the test tube (0778) to the 5 mL line with sample water.
2. Add 10 drops of *Barium Chloride Solution, 10% (6117). If
carbonates are present a white precipitate will form.
3. Add one Phenolphthalein Tablet (T-2246). Cap and mix until
tablet disintegrates. If no red color develops, the Hydroxide
Alkalinity is zero. If the sample turns red proceed to Step 4.
4. Fill the Direct Reading Titrator (0382) with the *Alkalinity
Titration Reagent (6102DR). Insert the Titrator tip in the center
hole of the test tube cap. While gently swirling the tube, slowly
press the plunger to titrate the sample until the red or pink color
disappears.
5. Read the Hydroxide Alkalinity directly from the Titrator scale in
ppm CaCO3.
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PHENOLPHTHALEIN (P) AL KA LIN ITY PRO CE DURE
1. Fill the test tube (0778) to the 5 mL line with sample water.
2. Add one Phenolphthalein Tablet (T-2246). Cap and mix until
tablet disintegrates. If a red color does not develop in the solution,
the P Alkalinity is zero. If a red color does develop, the P
Alkalinity is determined by titration in Step 3.
3. Fill the Direct Reading Titrator (0382) with *Alkalinity Titration
Reagent (6102DR). Insert the Titrator tip in the center hole of the
test tube cap.
4. While gently swirling the tube, slowly press the plunger until the
red color disappears. Record the P Alkalinity test result directly
from the Titrator in ppm CaCO3. Do not move Titrator plunger.
Save sample and remaining titrant for Total (T) Alkalinity test.
TO TAL (T) AL KA LIN ITY PRO CE DURE
If only Total Alkalinity is to be tested, perform Steps 1, 5 and 6, and
using a full Titrator for Step 6.
5. Carefully remove Titrator and cap from test sample from Step 4.
Add one BCG-MR Indicator Tablet (T-2311). Cap and mix until
tablet disintegrates.
6. Reinsert the Titrator tip into the test tube cap and continue the
titration until the green-blue color changes to pink. Read the test
result from the Titrator in ppm CaCO3.
When testing swimming pool water, consult the Acid Demand Index to
determine if the Total Alkalinity value is excessive. The Index will
indicate the recommended quantity of acid required to offset high
alkalinity content.
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CAL CU LA TION OF AL KA LIN ITY RE LA TION SHIPS
The results obtained from the Phenolphthalein and Total Alkalinity
determinations offer a means for the stoichiometric classification of the
three principal forms of alkalinity present in many water supplies. The
classification ascribes the entire alkalinity to bicarbonate, carbonate, and
hydroxide; and assumes the absence of other weak acids of inorganic or
organic composition, such as silicic, phosphoric, and boric.
This classification system further presupposes the incompatibility of
hydroxide and bicarbonate alkalinities in the same sample. Since the
calculations are on a stoichiometric basis, ion concentrations in the
strictest sense are not represented in the results.
According to this scheme:
A. Carbonate Alkalinity is present when the Phenolphthalein
Alkalinity is not zero but is less then the total alkalinity.
B. Hydroxide Alkalinity is present if the Phenolphthalein is more than
one-half the total alkalinity.
C. Bicarbonate Alkalinity is present if the Phenolphthalein Alkalinity
is less than one-half the total alkalinity.
The mathematical conversion of the results is shown in the table below:
Relationships Between Phenolphthalein Alkalinity, Total
Alkalinity, Carbonate Alkalinity & Hydroxide Alkalinity
Result of
Titration
Hydroxide
Alkalinity as
CaCO
3
Carbonate
Alkalinity as
CaCO
3
Bicarbonate
Alkalinity as
CaCO
3
P = 0 0 0 T
P < a T 0 2P
T - 2P
P = a T 0 2P 0
P > a T
2P - T 2 (T - P)
0
P = T T 0 0
LaMOTTE COM PANY
Helping Peo ple Solve An a lyt i cal Chal lenges
PO Box 329 • Chestertown • Mary land • 21620 • USA
800-344-3100 • 410-778-3100 (Out side U.S.A.) • Fax 410-778-6394
Visit us on the web at www.lamotte.com
SM
10/02
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