Hanna Instruments HI 38084 User Manual

Instruction Manual

HI 38084

Total Exchangeable

Acidity Test Kit

www.hannainst.com

Dear Customer,
Thank you for choosing a Hanna Product.
Please read the instruction sheet carefully before using the

test kit. It will provide you with the necessary information
for correct use of the kit. If you need additional information,
do not hesitate to e-mail us at [e-mail].

Remove the chemical test kit from the packing material and
examine it carefully to make sure that no damage has
occurred during shipping. If there is any noticeable dam­age, notify your Dealer or the nearest Hanna office
immediately.

Each kit is supplied with:

Potassium Chloride, 1 box (380 g);

•
Phenolphthalein Indicator, 1 bottle with dropper (20 mL);

•
HI 38084C-0 Titration Solution, 1 bottle (120 mL);

•
Demineralizer Bottle with filter cap for about 12 liters

•
of deionized water (depending on the hardness level

of water to be treated)

• 1 2-mm soil sieve;

• 1 large funnel;

• filter paper discs ∅ 120 mm (100 pcs);
1 plastic test tube (50 mL) with screw cap;

•

• 1 calibrated plastic vessel (50 mL);

• 2 sample cups (2 g);

• 1 sample cup (1 g);

;

1 plastic pipette (1 mL);

•

• 1 brush;
1 spoon.

•

Note: Any damaged or defective item must be returned in

its original packing materials.

SPECIFICATIONS

Range 0 to 2.5 meq/100 g
Smallest Increment 0.1 meq/100 g
Analysis Method Titration
Sample Size 5 g of soil
Number of Tests 100
Case Dimensions 235x175x115 mm (9.2x6.9x4.5")

Shipping Weight 1027 g (36.2 oz.)

Note: TEA is Total Exchangeable Acidity; meq/100 g is

milliequivalent per 100 grams.

SIGNIFICANCE AND USE

The total exchangeable acidity (TEA) is a measure of the
amount of acidic cations (hydrogen, aluminum, iron and
manganese) present in soil. It is expressed in milliequivalent
per 100 grams (meq/100 g) of soil. The more acidic it is a
soil, the lower the soil pH value will be. Soils in humid
regions normally accumulate increasing amounts of ex­changeable acidity as they get older. Soil acidity may
develop toxicity that can damage or kill plants.

CHEMICAL REACTION

The extraction method is the potassium chloride method.
The acidic cations are firstly leached from the soil and then

titrated with a standard alkali. The reaction endpoint is
visually indicated by a color change (from colorless to pink)
of the indicator reagent.

ISTR38084 02/00 PRINTED IN ITALY

WHEN TO TEST YOUR SOIL

Soil should be tested not only when the plant appears to
be unhealthy (yellow leaves or stunted growth), but prior to
seeding, planting and fertilizing as well as when other
material such as manure or compost has been added.

SAMPLING

1) Soil Sample Extraction
– Within a large homogeneous area, take 1 or 2 samples

per 1000 m2 (0.25 acre).

– Even for smaller areas, 2 samples are recommended

(the more samples, the better the end-results, be­cause the end sample is more representative).

– For a small garden or plot, 1 sample is sufficient.

2) Avoid extracting samples from soil presenting obvious

anomalies and from border areas (near ditches and roads).

3) Sample quantity:

Take the same quantity of soil for each sample. For ex­ample, use bags with similar dimensions (1 bag per
sample).

4) Depth of extraction:

General: dig and discard 5 cm (2") of topsoil
For lawns: take the sample at a depth of 5 to 15 cm (from
2" to 6").
For other plants (flowers, vegetables, shrubs): from 20 to
40 cm of depth (8" to 16").
For trees: Samples from 20 to 60 cm of depth (8" to 24'’).

5) Mix all the samples together to obtain a homogeneous

mixture of soil, discarding stones and vegetable residues.

6) From this mixture, take the quantity of soil that you

need for the analysis.

7) Crumble the large chunks and distribute the soil sample

on paper or plastic to air dry it.

8) Use a small bar to crush the air dried sample and pass it

through the 2-mm soil sieve.

INSTRUCTIONSSAMPLING PROCEDURE

READ THE ENTIRE INSTRUCTIONS BEFORE USING THE KIT

• Remove the cap
and fill the Dem­ineralizer Bottle
with tap water.

• Replace the cap
and shake gen­tly for at least
2 minutes. The
demineralized
water is now
ready.

• Flip open the top of the Deminer­alizer Bottle cap. By gently
squeezing the bottle, add dem­ineralized water to the large (50
mL) test tube up to the 50 mL
mark.

• Add 2 measures of the large (2 g) sample cup of
Potassium Chloride (add full cups and discard the excess
soil by using the spoon handle).

• Place the cap on the
tube and shake it sev­eral times until the
reagent has completely
dissolved. The potassium
chloride extractant so­lution is now ready.

• Place the funnel on the top of
the beaker.

50 mL

x 2

• Fold a filter paper disc twice as shown in the figure.

• Separate one side from the other
three to form a cone.

• Place the folded filter disc into the funnel and wet it
with some drops of deionized water.

• Add into the cone 2 measures of the large (2 g) sample
cup and 1 measure of the small (1 g) cup of sieved soil
(full cups but discard the excess soil by using the spoon
handle).

x 2 x 1

of drops being added to the solution.

• Keep adding the titrant until the pink color developed
does not disappear upon gently swirling (the solution
changes from colorless to pink).

• If necessary refill the pipette with titrant. Record the
number of drops needed to obtain the color change and
calculate the Total Exchangeable Acidity (TEA) as fol­lows:

TEA (meq/100 grams of soil) = drops added/10

• Every 30 minutes add 10
mL of potassium chloride
extractant solution to the
soil in the cone. Repeat
this operation 5 times.

• Then rinse the soil sample twice, at 30 minute inter­vals, with 10 mL of deionized water. The extract is
collected in the beaker.

DETERMINATION OF THE TOTAL EXCHANGEABLE ACIDITY

• Add 4 drops of Phenolphthalein Indicator to the extract
and swirl to mix.

x 4

• Fill the pipette with HI 38084C-0 Titration Reagent.
Add the titrant to the sample drop by drop, while
swirling and keeping an accurate count of the number

REFERENCES

APHA, AWWA, WEF, Standard Methods, 20th edition, 1998.
P. Sequi, Chimica del suolo, Patron Editore, Ed. 1991.

HEALTH AND SAFETY

The chemicals contained in this kit may be hazardous if
improperly handled. Read the relevant Health and Safety
Data Sheet before performing this test.