PHENOLPHTHALEIN/TO TAL AL KA LIN ITY
WARNING! This set contains chemicals
that may be harmful if misused. Read
cautions on individual containers
carefully. Not to be used by children
except under adult supervision
TEST KIT
MODEL WAT-MP-DR • CODE 4533-DR
QUANTITY CONTENTS CODE
100 Phenolphthalein Tablets T-2246-J
100 BCG-MR Indicator Tablets T-2311-J
60 mL *Alkalinity Titration Reagent B *4493DR-H
1 Test Tube, 5-10-15 mL, glass, w/cap 0778
1 Direct Reading Titrator, 0-200 Range 0382
*WARNING: Reagents marked with an * are considered to be potential health
hazards. To view or print a Material Safety Data Sheet (MSDS) for these reagents
go to www.lamotte.com. To obtain a printed copy, contact LaMotte by e-mail,
phone or fax.
To order individual reagents or test kit components, use the specified code
number.
NOTE: Read the Direct Reading Titrator Instruction Manual (1649)
before proceeding. Each minor division on the Titrator scale equals 4 ppm
CaCO3.
PHENOLPHTHALEIN (P) AL KA LIN ITY PRO CE DURE
1. Fill test tube (0778) to 5 mL line with sample water.
2. Add one Phenolphthalein Tablet (T-2246). Cap and mix until tablet
disintegrates. If solution does not turn red, P Alkalinity is 0. If
solution turns red, proceed to Step 3.
3. Fill the Direct Reading Titrator (0382) with *Alkalinity Titration
Reagent B (4493DR). Insert Titrator into center hole of test tube cap.
4. While gently swirling tube, slowly press plunger to titrate until red
color disappears. Read the test result directly from the scale where the
large ring on the Titrator meets the Titrator barrel. Record as ppm P
Alkalinity as CaCO3.
EXAMPLE: Plunger tip is 3 minor divisions below line 80. The test
result is 80 plus 12 (3 divisions x 4) equals 92 ppm.
5. If plunger tip reaches the bottom line on the Titrator scale (200 ppm)
before the color change occurs, refill the Titrator and continue the
titration. When recording test result, be sure to include the value of
original amount of reagent dispensed (200 ppm).
NOTE: Do not move Titrator plunger after the P Alkalinity
endpoint has been obtained. The titration is continued in the T
Alkalinity procedure.
TO TAL (T) AL KA LIN ITY PROCEDURE
6. Being careful not to move plunger, remove Titrator and cap from test
tube containing sample that was titrated in Step 4.
7. Add one BCG-MR Tablet (T-2311). Cap and shake until tablet
disintegrates. Solution will turn green-blue.
8. Reinsert Titrator in cap and continue titration until color changes
from green-blue to pink. Read the test result directly from the scale
where the large ring on the Titrator meets the Titrator barrel. Record
as ppm T Alkalinity as CaCO3. Be sure to include in test result value
the total amount of titration reagent dispensed (i.e. see Step 5).
9. If only Total Alkalinity is to be tested, perform Steps 1,7 and 8 only,
using a full Titrator in Step 8.
CAL CU LA TION OF AL KA LIN ITY RE LA TION SHIPS
Results obtained from Phenolphthalein and Total Alkalinity
determinations offer a means for the stoichiometric classification of three
principal forms of alkalinity present in many water supplies. Classification
attributes the entire alkalinity to bicarbonate, carbonate and hydroxide;
and assumes absence of other weak acids of inorganic or organic
composition, such as silicic, phosphoric, and boric. This classification
system further assumes incompatibility of hydroxide and bicarbonate
alkalinities in the same sample. Since 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 Phenolphthalein Alkalinity is
not zero but less than the Total Alkalinity.
B. Hydroxide Alkalinity is present if Phenolphthalein Alkalinity is more
than one-half the Total Alkalinity.
C. Bicarbonate Alkalinity is present if Phenolphthalein Alkalinity is less
than one-half the Total Alkalinity.
Mathematical conversion of the result is shown in the following table:
Relationships Between Phenolphthalein,
Total, Carbonate, Bicarbonate & 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<1/2T 0 2P
T-2P
P=1/2T 0 2P 0
P>1/2T
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
8.11
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