LaMotte WAT-MPH-DR User Manual

HY DROX IDE, PHENOLPHTHALEIN

L

Mott

& TO TAL AL KA LIN ITY

DROP COUNT METHOD

MODEL MPH-DC • CODE 7515

QUANTITY CONTENTS CODE

100 Phenolphthalein Tablets T-2246-J

100 BCG-MR Indicator Tablets T-2311-J

30 mL *Barium Chloride Solution, 10% *6117-G

2 x 60 mL *Alkalinity Titration Reagent *6102PS-H

1 Test Tube, 5-10-15 mL, glass, w/cap 0778

1 Pipet, plain, plastic 0352

1 Acid Demand Index 1546

*WARNING: Reagents marked with a * are considered to be potential health
hazards. To view or print a Material Safety Data Sheet (MSDS) for these reagents
see MSDS CD or www.lamotte.com. To obtain a printed copy, contact LaMotte by
email, phone or fax.

To order individual reagents or test kit components, use the specified code
number.

HY DROX IDE AL KA LIN ITY

1. Fill test tube (0778) to 5 mL line with sample water.

2. Add 10 drops of *Barium Chloride Solution, 10% (6117). A white

precipitate will form if carbonates are present.

3. Add one Phenolphthalein Tablet (T-2246). Cap and mix until tablet
disintegrates. If solution does not turn red, the Hydroxide Alkalinity
is zero. If solution turns red, proceed to Step 4.

4. Fill the pipet (0352) with *Alkalinity Titration Reagent (6102PS).
Hold pipet vertically. While gently swirling tube, add *Alkalinity
Titration Reagent, one drop at a time, until color changes from red to
colorless. Count the number of drops added.

5. Multiply number of drops added in Step 4 by 10. Record as ppm
Hydroxide Alkalinity as CaCO3.

Number of Drops of Titration Reagent x 10 =

ppm Hydroxide Alkalinity expressed as

ppm Calcium Carbonate (CaCO3)

PHENOLPHTHALEIN (P) AL KA LIN ITY

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 turns red proceed to Step 3. If solution does
not turn red, P Alkalinity is zero.

3. Fill pipet (0352) with *Alkalinity Titration Reagent (6102PS). Hold
pipet vertically. While gently swirling tube, add *Alkalinity Titration
Reagent, one drop at a time, until color changes from red to colorless.
Count the number of drops added.

4. Multiply the number of drops added in Step 3 by 10. Record as ppm
P Alkalinity as CaCO

3.

Number of Drops of Titration Reagent x 10 =

ppm Phenolphthalein Alkalinity expressed as

ppm Calcium Carbonate (CaCO3)

5. Save sample for T Alkalinity test.

TO TAL (T) AL KA LIN ITY

1. Use the sample from the P Alkalinity test, or fill the test tube (0778)
to the 5 mL line with sample water.

2. Add one BCG-MR Indicator Tablet (T-2311). Cap and mix until
tablet disintegrates.

3. Fill the pipet with *Alkalinity Titration Reagent (6102PS). Hold
pipet vertically. While gently swirling tube, add *Alkalinity Titration
Reagent, one drop at a time, until color changes from green to pink.
Count the number of drops added.

4. Multiply number of drops used in Step 3 by 10. Record as ppm
T Alkalinity as CaCO3.

NOTE: If the same sample is used for both the P and T Alkalinity
tests, add both test results to calculate T Alkalinity.

Number of Drops of Titration Reagent x 10 =

Total Alkalinity expressed as

ppm Calcium Carbonate (CaCO3)

When testing swimming pool water, consult the Acid Demand Index
(1546) to determine if the Total Alkalinity value is excessive. The Index
will indicate the recommended quantity of acid required to offset high
alkalinity content.

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 attributes the entire alkalinity to bicarbonate, carbonate and
hydroxide, and assumes the absence of other weak acids of inorganic or
organic composition, such as silica, phosphoric and boric.

This classification system assumes 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.

Ac cord ing to this scheme:
A. Carbonate alkalinity is present when the phenolphthalein alkalinity

is not zero but is less than the total alkalinity.

B. Hydroxide alkalinity is present if the phenolphthalein alkalinity 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.

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

1

P<

T 0 2P

2

1

P=

T 0 2P 0

2

1

P>

T

2

2 (T-P) 2 (T-P)

T-2P

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 USA) • Fax [phone]

Visit us on the web at www.lamotte.com

SM

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