LaMOTTE-MOR GAN
L
Mott
SOIL pH TEST KIT
MODEL ST-M • CODE 5023
QUANTITY CONTENTS CODE
60 mL *Duplex Indicator *2221-H
60 mL Bromcresol Green Indicator 2207-H
60 mL Chlorophenol Red Indicator 2209-H
60 mL Bromthymol Blue Indicator 2210-H
60 mL Phenol Red Indicator 2211-H
120 mL Distilled Water 5115PT-J
2 Double Spot Plates, plastic 0159
1 Rod, plastic 0520
1 Color Chart, Soil Duplex 1313
1 Color Chart, Bromcresol Green 1328
1 Color Chart, Chlorophenol Red 1329
1 Color Chart, Bromthymol Blue 1331
1 Color Chart, Phenol Red 1332
1 LaMotte Soil Handbook 1504
*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.
PRO CE DURE
1. Fill one of the large depressions in a spot plate (0159) with sample
soil. Do not pack the soil down.
2. Place spot plate on a level surface. Add *Duplex Indicator (2221)
drop by drop until the soil is thoroughly saturated. Do not overfill. If
sample is flooded, some indicators will not react completely with soil,
producing a false reading. Wait 3 minutes.
3. Tilt the spot plate so that indicator flows down channel and collects
in smaller depression. If necessary, use the pointed plastic rod to start
the flow.
4. Match color in small depression plate to a color standard on the
Duplex Color Chart (1313).
5. Use result from Step 4 to choose a narrow range indicator for more
precise pH measurements. Use chart below to determine the proper
narrow range. Choose the indicator with the midpoint closest to
sample pH.
6. Using a second portion of soil and the narrow range indicator, repeat
Steps 1-5 in a clean depression. Consult Chapter Four of the LaMotte
Soil Handbook (1504) for interpretation of the narrow range pH test
result.
Indicator Range
Midpoint
Val u e
Bromcresol Green (2207) 3.8 – 5.4 4.6
Chlorophenol Red (2209) 5.2 – 6.8 6.0
Bromthymol Blue (2210) 6.0 – 7.6 6.8
Phenol Red (2211) 6.8 – 8.4 7.6
NOTES & PRE CAU TIONS
1. Do not conduct tests in a closed stable in the presence of fumes from
decomposing manure, or in a laboratory where ammonia or acid
fumes are present.
2. Compare colors in diffused daylight. Comparison of colors in direct
sunlight or artificial light may result in incorrect readings.
3. Wash spot plate with Distilled Water (5115PT) prior to testing,
particularly when alkaline soils are to be tested. A change of color as
liquid passes down the channel indicates that impurities on the plate
have interfered in the test reaction.
4. Avoid contact between soil sample and hands, fertilizers, sprays, etc.
See the LaMotte Soil Handbook for a detailed discussion of collection,
preparation, and handling of soil samples.
5. Some soils may be more acid than pH 3.8; others may be more
alkaline than pH 8.4. LaMotte Company furnishes narrow range
indicators and color charts to measure these extreme ranges:
Bromphenol Blue, pH 3.0 - 4.6; Thymol Blue, pH 8.0 - 9.6.
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.)
Visit us on the web at www.lamotte.com
®
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